OzVMX Forum
Clubroom => Tech Talk => Topic started by: 211 on July 16, 2014, 04:58:44 pm
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Hi All
would be really interested in what the opinions are on magnesium and its end of life. Eventually we are going to have to recognise that a lot of hubs (for example) are made of the metal will / have reached their end date and decide how we account for it - or be flexable in accepting the issues and find a solution. That may be to allow some lattitude on hubs - I dont know, but Im interested to start a conversation on the subject.
My point I guess is in light of not being able to ride my 74 KX because the sprocket carrier is cracked and the bikes had a reputation even back in the 70s of the brake backing plate breaking and trying to kill you. Maico is another example.
:)Please - keep it constructive
DT
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Are there any brands that don't have a viable alloy hub option from the same racing era?
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Early Magnesium Road Racing ( Light wieght Campagnolo ) wheels were only used for 2 Seasons by Factory Teams in the 70's,
Castings and Technologies have improved heaps since then and a lot about the life of was unknown at that time, hence precautions!
In the early days most of the casting for the really thin lightwieght stuff was done in Italy where the sand and envoiromental conditions were favourable.
It took quite a while for Japan to make their own Racing Mags.
For sure Magnesium can be very porous and can erode.
As for the life, its case by case, how long is a piece of string?
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As I have said previously, Look at the Historic Road Race rules.
They had recognised this problem a long time ago and permit replica parts to be approved.
The key to it is be approved, there would need to be a list of approved parts.
You may not be able to get an exact replica. Machining a hub from billet alloy would be cheaper and probably stronger than a casting. Castings are only viable if there is a reasonable number made.
I have proposed the above in my response I will send to MA RE the rules.
Kevin
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Dave I am in the same position re the 74 KX hubs , I don't have a solution as yet . Was going to look at getting a price to CNC a sprocket carrier and backing front backing plate . Cost for single items will probably make it non viable but will look into it .
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God the last thing I want is to have my KX's knocked back at scrutineering because they have magnesium hubs, bloody hell drop the subject and maybe raise it if some hubs start breaking!
It's more about allowing billet alloy backing plates and some alternate hubs to be legal as a safety issue..
Don't get excited It says nothing about banning magnesium does it?
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God the last thing I want is to have my KX's knocked back at scrutineering because they have magnesium hubs, bloody hell drop the subject and maybe raise it if some hubs start breaking!
It's more about allowing billet alloy backing plates and some alternate hubs to be legal as a safety issue..
Don't get excited It says nothing about banning magnesium does it?
Cool, just reading between the lines. Kinda always on the defensive ;-)
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Please !
its not about banning the parts its about alternatives.
I have fitted a 75 KX front wheel to my 74 KX as its an alloy pressure casting and a good part although the brakes are still crap. Im the first to admit it isnt legal to use hence its a garage queen and something Im not used to having. I have the same problem with the KX450 and ATM im looking at F11 hubs to see if that fits including the 74 sproket mount - Bill if you have an F11 a measure would be handy.
I spent some time restoring a 74 YZ250 and in the course of selecting a rear wheel to use I dropped it and the hub smashed into 10 parts - I guess this is the point.
The RR stuff is same problem but presents a lot more serious problem for them; Im just looking 2-5 years hence when we will have to decide how to keep old bikes still on the tracks.
DT
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COMMON SENSE ISN'T THAT COMMON
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Didn't Rob Tumes go down in a heap at Mt Kembla Nats when front hub fell apart on his KX ? think he went to ts185 front hub, but not sure.
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Dave - Bill , I think Bazza is right - swap the front and rears out for TS 185.
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So:
74 KXes can use TS185 hubs (and brake plates?);
YZ-As can use MX-A parts.
What other bikes have magnesium hubs?
CZs run them, but don't have a problem?
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Shhh stew. don't tell everyone how light and strong the front 185 hubs are even though they are bigger than TM125. ;D
Lace them to a decent ally rim and you have something that brakes okay with a lot less weight. I really don't know why Suzuki didn't use that hub on more models.
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Many magnesium Maico front backing plates have failed sending the rider over the bars. That's why you see so many billet alloy ones about...
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So:
74 KXes can use TS185 hubs (and brake plates?);
YZ-As can use MX-A parts.
What other bikes have magnesium hubs?
CZs run them, but don't have a problem?
CZs run a different magnesium alloy than Japanese bikes but it doesn't stop them having issues, I've seen photos of completely white hubs that have snapped in places.
There is a company in the England that makes replica hubs in LM25 aluminum alloy specifically for the owners of british thumpers running CZ wheels & forks, new hubs are also available from a supplier in Poland who may be getting them made by the original makers in the Czech republic
Never seen an issue with the front back plates which are also magnesium
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Saw the Maico billet plates at the Buladelah Vinduro on the weekend. One on a 490, the other on his 250. They sure look nice.
The owner told me he just built the 490 up and took it for a squirt down the road. Got up to approx 50 kph and pulled the front brake on to turn around. The front backing plate shattered, spun around and smashed a section of the lower fork leg clean off. Scary shit.
Then he put the billet ones on. Happy days now
I can see why guys are nervous of the old magnesium plates. Safety HAS to come first and foremost.
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Shane .... sorry . The cats out of the bag now ;D
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Things like this are a real non issue. A) amend the rules to allow a similar or reproduction part to be used B) remove intact part have it 3D scanned scour the net looking for a company to reproduce the item. Top it off with a bit of CNC, there is even a member here that can cast reproduction items.
Not a lot of foundries want to cast magnesium, think there is only 1 in Australia.
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Are the billet alloy plates heavier or lighter than the stock magnesium ones?
Lots of drum braked Yamahas used magnesium brake plates - never heard of them being a problem. And there are alloy alternatives if anyone is nervous.
So:
74 KXes can use TS185 hubs (and brake plates?);
YZ-As can use MX-A parts;
CZs have similar aluminium alloy replacements available.
The only real problem is the Maico brakes plates?!
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there aren't many Maico AW mag hubs in service any more - all cracked....
PES/ CCM Britain is making replica hubs + backing plates to replace the CCM mag items, which can fail , or are regarded as valuable.. I think the modern hubs offer better braking though ( materials +accuracy)
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Saw the Maico billet plates at the Buladelah Vinduro on the weekend. One on a 490, the other on his 250. They sure look nice.
The owner told me he just built the 490 up and took it for a squirt down the road. Got up to approx 50 kph and pulled the front brake on to turn around. The front backing plate shattered, spun around and smashed a section of the lower fork leg clean off. Scary shit.
Then he put the billet ones on. Happy days now
I can see why guys are nervous of the old magnesium plates. Safety HAS to come first and foremost.
Exactly the same thing happened to me!
I was testing my 490 Maico beside a busy road and pulled front brake on in 5th gear and backing plate mount sheared, snapped fork bottom off at axle and sent me careening onto the busy road with no steering narrowly missing several cars! Scariest thing ever!
Hence the Yamaha front wheel in my Maico and my concern over the std backing plate rule in the new proposed Evo rules.. understandable I think.
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Also saw brett downs front brake plate break at Harrisville on a bike I used to own (maico MC250 81) - broken ribs and a wrecked helmet a year or so ago.
Id bought the bike with a Yamaha wheel (the original owner had done the conversion in the 80s)but I changed it back...
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Issues of this nature will become more and more common as itime goes on i guess.
Its good to be proactive about it now and look at solutions . Saftey must be paramount followed by era sympathy . The point has already been raised that the PES CCM hubs offer better braking performance over the originals i cant see how this is a problem as long as they are available to anyone .
I dont like to see old bikes with lots of polished shiny billet , and would prefer if the owners would paint or coat items to a more period finish.
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Are the billet alloy plates heavier or lighter than the stock magnesium ones?
Lots of drum braked Yamahas used magnesium brake plates - never heard of them being a problem. And there are alloy alternatives if anyone is nervous.
So:
74 KXes can use TS185 hubs (and brake plates?);
YZ-As can use MX-A parts;
CZs have similar aluminium alloy replacements available.
The only real problem is the Maico brakes plates?!
Nath 74 KXs have a brake locking indent in the backing plate that is very wide ( like the Hondas) so alternatives (other than 75/76 KXs) are not a bolt on option i have looked into it .
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Didn't Rob Tumes go down in a heap at Mt Kembla Nats when front hub fell apart on his KX ? think he went to ts185 front hub, but not sure.
Not without a fork change to Mike
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OK, so the 74 KXes (hubs and brake plates?) and the Maico brake plates are the real problems?
Kawis may be able to use F11 parts, TBC.
Any others?
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Saw the Maico billet plates at the Buladelah Vinduro on the weekend. One on a 490, the other on his 250. They sure look nice.
The owner told me he just built the 490 up and took it for a squirt down the road. Got up to approx 50 kph and pulled the front brake on to turn around. The front backing plate shattered, spun around and smashed a section of the lower fork leg clean off. Scary shit.
Then he put the billet ones on. Happy days now
I can see why guys are nervous of the old magnesium plates. Safety HAS to come first and foremost.
Exactly the same thing happened to me!
I was testing my 490 Maico beside a busy road and pulled front brake on in 5th gear and backing plate mount sheared, snapped fork bottom off at axle and sent me careening onto the busy road with no steering narrowly missing several cars! Scariest thing ever!
Hence the Yamaha front wheel in my Maico and my concern over the std backing plate rule in the new proposed Evo rules.. understandable I think.
What proposed rules?? You cannot even resist when Dave is trying to genuinely get feedback on a serious issue. Strictly speaking the current rules don't allow billet backing plates either but lets not turn this into another BUN fight.
Heaven VMX never questions the billet backing plates for Maicos because it is a safety issue they offer no real performance gain over the originals except they are trouble free and don’t try to kill anyone.
Congratulations Dave on opening a serious issue up to constructive input. Parts that allow bikes to stay on the track by replacing suspect or unobtainable parts are essential.
***This my personal input not Heaven VMX
Classic Trials bikes in the Pre65 class also have issues with wheel hubs and brake components. They have chosen a good hub from the period, in the case of Pre65 that is a Honda hub and brake available in 1964 (only just). This hub just happens to be virtually identical to the Postie bike hubs still available today. This is a very cheap and easy solution that works and is equal for everyone.
Possibly a similiar solution for our sport could be the Yamaha conical front and alloy rear hubs pretty much standard on every Yammie dirt bike from about ’71 until ’80 including trail bikes. I know this is not a purist approach but ensures a ready supply of wheels with very affordable rims and spokes, good brakes. I realise another hub would be required for right chain final drive machines but I am sure another hub could be nominated.
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I don’t understand the dilemma
Replica parts are accepted, so are these billet backing plates really that different from stock?
They may have a slightly different outside appearance but the inside would have to be essentially the same to be able to fit and work.
How exact does a replica need to be?
The only way I can see that a billet backing plate can be a performance advantage is if they are stiffer, and if that’s the case then the original backing plate that is flexing will be prone to breaking one day. If you keep bending a piece of metal back and forth it will eventually fatigue and break.
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I have fond memories of the VB Montesa but with Magnesium Marzzochis there is no way I would ride one in anger
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My '79 Maico front backing plate failed, yet my '64 CZ is still ok (I hope). An example of why we have to be carefull with any proposed rule changes. It's so easy to cure one perceived problem and create a heap of new ones.
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Exactly Col, that's what I was referring to in my previous post.
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Mag wheels made for racing cars had an EXPIRY DATE stamp. Thats enough for me! If they don't have a date stamp that' s a bit suss either they are not Mag or the manufacturer is negligent.
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Why does magnesium die?
My memory of high-school chemistry lessons is poor, but I thought the main problem is that the material ages, AND it has a poor fatigue life.
Most car/bike forums seem to point the finger at corrosion, which seems unlikely.
What I'm getting at, is whether x-raying and/or magna fluxing are useful procedures?
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I don't see a problem with having replica parts made. Replica parts keep old bikes running SAFELY. Magnesium in particular fatigues because of light weight and poor metallurgy from the factory of the time. Add in water onto any non painted part (inside of brake plate and hub) and corrosion starts very quickly.
Just like wide foot pegs are considered to be a safety improvement, so should certain magnesium part replacement.
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Historic Road Racing and Historic Car Racing already recognise problems with old parts and to my knowledge both permit replica parts. There are so many parts that I think you can build a brand new Manx Norton from new parts. You can also get a brand new 67 Mustang and 68/69 Camaro unibody for each and all the other body panels.
So we just need the correct rules to permit it.
Also why does anyone think wide pegs are permitted. There is nothing in the rules that say they are. It is just another one of those unwritten rules.
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Historic Road Racing and Historic Car Racing already recognise problems with old parts and to my knowledge both permit replica parts. There are so many parts that I think you can build a brand new Manx Norton from new parts. You can also get a brand new 67 Mustang and 68/69 Camaro unibody for each and all the other body panels.
So we just need the correct rules to permit it.
Also why does anyone think wide pegs are permitted. There is nothing in the rules that say they are. It is just another one of those unwritten rules.
The replica Manx Nortons still look like a Manx not like those awefull looking CNC backing plates. Someone should give an original Maico plate to that guy who was doing the Aluminium clutch covers and get them cast, same with mag hubs. A good casting shop can use the original as a patern in most cases and it would be way cheaper than the CNC crap.
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Nathan
If you want to know why Mg corrodes so quickly, then check out the link below but in short it is a very sacrificial & reactive metal so when placed in an environment with disimilar 'other' metals, it will sacrificially dissovle/corrode to protect the other metals higher than itself on the galvanic table. There are several new technologies in the marketplace now that enhance the corrosion protection & peformance on Mg but not viable &/or cost effective outside of aviation/aerospace etc. It has also been overtaken by the use of carbon fibre in other peripheral applaictions.
http://en.wikipedia.org/wiki/Galvanic_series
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Im grateful for finding parts in good condition where ever and if I can find them and I don't have particularly rare machines. this being the case some parts are getting almost impossible to locate.
its even harder if you have something exotic
if someone can manufacture a replica that operates the same and looks the same as OEM then I would and do use them.
if a product is better than OEM quality for safety reasons I would use it as safety is paramount. if it also has a performance benefit as in limit flex in the CNC backing plate situation this should also be considered admissible as no one wants an avoidable injury to deal with. So what if it looks different . An EH holden looks bloody stupid with seat belts and they didn't come with steel belt radials but they are safety modifications and they work and keep people alive.
Safety first guys, none of us are getting any younger and I would like to see more of us enjoying the sport for quite a few years to come.
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How safe would it be to use a pair of 1977 magnesium Marzocchi forks that have some corrosion pitting in the legs?
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Nathan
If you want to know why Mg corrodes so quickly, then check out the link below but in short it is a very sacrificial & reactive metal so when placed in an environment with disimilar 'other' metals, it will sacrificially dissovle/corrode to protect the other metals higher than itself on the galvanic table. There are several new technologies in the marketplace now that enhance the corrosion protection & peformance on Mg but not viable &/or cost effective outside of aviation/aerospace etc. It has also been overtaken by the use of carbon fibre in other peripheral applaictions.
http://en.wikipedia.org/wiki/Galvanic_series
Yeah, I'm down with the reactivity of metals stuff.
I just have this recollection (which may be wrong!) about Mg alloys having issues with precipitation hardening all by themselves, over time. So even a brand new magnesium part that is sitting on a nice dry shelf somewhere is deteriorating, and closer to failure than it was when it was made.
I'm my memory is wrong, then I don't really understand what the issue is: If you want to avoid the risk then you manage the risk by replacing the parts or having them crack tested.
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How safe would it be to use a pair of 1977 magnesium Marzocchi forks that have some corrosion pitting in the legs?
I have no idea on the metallurgy
I just wouldn't do it
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theres not much i cant cast in alumium backing plates for brakes ezey but will it be strong with out heat treating i dont know
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What's happened with the rule book????
This is from my 09 book, it seems to have been removed from the current version
Why was this changed? Are my replica frames now not accepted with the current rules? WTF
(http://i15.photobucket.com/albums/a393/gmcloa/Misc%202/MA-book-2_zps348f8bf6.jpg) (http://s15.photobucket.com/user/gmcloa/media/Misc%202/MA-book-2_zps348f8bf6.jpg.html)
Just spied a picture of a billet Maico backing plate, looked like a reasonably faithful replica to me (from what I could see of it)
I can see no reason why the replica rule would have been taken out of the book
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theres not much i cant cast in alumium backing plates for brakes ezey but will it be strong with out heat treating i dont know
The early Maico backing plate are aluminium and I doubt they were heat treated. The alum one are a bit thinker than the mag one. Think I've got one of each around here somewhere if you want to have a look at one. What sort of cost un-machined do you think they would be?
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What's happened with the rule book????
This is from my 09 book, it seems to have been removed from the current version
Why was this changed? Are my replica frames now not accepted with the current rules? WTF
(http://i15.photobucket.com/albums/a393/gmcloa/Misc%202/MA-book-2_zps348f8bf6.jpg) (http://s15.photobucket.com/user/gmcloa/media/Misc%202/MA-book-2_zps348f8bf6.jpg.html)
Just spied a picture of a billet Maico backing plate, looked like a reasonably faithful replica to me (from what I could see of it)
I can see no reason why the replica rule would have been taken out of the book
Its a bit legalistic but you don't make a 'replica' anymore, you make a 'representation' of what appeared in the era. Replica has the meaning that it is exactly the same , representation is sorta kinda like if you squint ;)
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What's happened with the rule book????
This is from my 09 book, it seems to have been removed from the current version
Why was this changed? Are my replica frames now not accepted with the current rules? WTF
(http://i15.photobucket.com/albums/a393/gmcloa/Misc%202/MA-book-2_zps348f8bf6.jpg) (http://s15.photobucket.com/user/gmcloa/media/Misc%202/MA-book-2_zps348f8bf6.jpg.html)
Just spied a picture of a billet Maico backing plate, looked like a reasonably faithful replica to me (from what I could see of it)
I can see no reason why the replica rule would have been taken out of the book
I have just put another post up that also addresses this. Geoff is right something like this needs to go back in. And yes calling them a representation of a part makes sense, an exact replica of a magnesium hub will still have the same problem.
kdx 175 also makes a point. Hubs and backing plates are different to clutch covers etc. They are critical stressed parts and really need to be improved for safety.
Really we have two different types of machines.
1. Restored bikes were everything is original
2. Race bikes were we should permit slight improvements for safety.
CAMS recognises this with the Touring Car Masters. The cars have better brakes, gearbox and diffs etc. They look like the cars from the period but are safer.
There is no way I will ever go back to the standard front brake backing plate on my 490 Maico. There are enough examples of how dangerous the old ones have become. I also can not afford to change back.
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There were submission to include such clauses considered by the Commission this year but rejected.
Read the CMX/CDT commission minutes on the MA site.
Agree that the rules need an overal clause that defines
1) What is a replica (or representation)
2) What is a period after market item and how it is proven
3) What are the major components
4) What are minor items and indicate that they are restriction free (basically the rules in there literal reading don't allow modern handlebars etc, we all know they do)
5) What is a modification (the NSW RTA, called somthing else these days, considers window tint as a modification or fitting allow wheels to a car) eg is fitting one of those easy pull clutch levers a modification? I don't think so but the rules are mute on such things.
I know the usual characters will jump on every word of my post as usual but read the rules and try to define these things, I don't mean what you think or what 'we know is OK' but read what the rules say.
16.15.10.1 Acceptable for the pre 75 class are machines and components built up to and including the 1974 model. The only exception to this rule is where the model remains unaltered after this date.
Which components must be built in 1974 or before? Is that every component or just major components. I would think practically it means major components but for someone coming into the sport that seek clarrification from their club who may have a different take on it.
This is not having a go at the CMX/CDT Commission as I can imagine that the rules are a real pain to administer and the people involved would have a clear interpretation in their mind when drafting rule but the resulting rule needs to be clear to most people.
I am disappointed that the Commission seems most often to reject submissions without looking at them and consider using their own considerable experience to correct minor problems with submissions rather than just rejecting it outright because it has an unintended consequence.
I am not talking about submissions to the MA Board regarding recomendations, as the MA Board can not accept any rule submissions at this point they can only accept or reject the recommendations of the Commission. I am referring to submissions lodged before March each year to the Commissions for consideration.
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There were submission to include such clauses considered by the Commission this year but rejected.
Read the CMX/CDT commission minutes on the MA site.
Agree that the rules need an overal clause that defines
1) What is a replica (or representation)
2) What is a period after market item and how it is proven
3) What are the major components
4) What are minor items and indicate that they are restriction free (basically the rules in there literal reading don't allow modern handlebars etc, we all know they do)
5) What is a modification (the NSW RTA, called somthing else these days, considers window tint as a modification or fitting allow wheels to a car) eg is fitting one of those easy pull clutch levers a modification? I don't think so but the rules are mute on such things.
I know the usual characters will jump on every word of my post as usual but read the rules and try to define these things, I don't mean what you think or what 'we know is OK' but read what the rules say.
16.15.10.1 Acceptable for the pre 75 class are machines and components built up to and including the 1974 model. The only exception to this rule is where the model remains unaltered after this date.
Which components must be built in 1974 or before? Is that every component or just major components. I would think practically it means major components but for someone coming into the sport that seek clarrification from their club who may have a different take on it.
This is not having a go at the CMX/CDT Commission as I can imagine that the rules are a real pain to administer and the people involved would have a clear interpretation in their mind when drafting rule but the resulting rule needs to be clear to most people.
I am disappointed that the Commission seems most often to reject submissions without looking at them and consider using their own considerable experience to correct minor problems with submissions rather than just rejecting it outright because it has an unintended consequence.
I am not talking about submissions to the MA Board regarding recomendations, as the MA Board can not accept any rule submissions at this point they can only accept or reject the recommendations of the Commission. I am referring to submissions lodged before March each year to the Commissions for consideration.
At the risk of another mess
1/ something that is a replica of the original part. not something made in a mill that replaces the part - however these is latitude given here and the Maico backing plate item is a good example. An example or a replica is a MCS plastics M5Y Rear guard that is an exact TM Suzuki replica.
2/ something like a DG head or alloy swing arm etc. Made in the period for the period.
3/ engine, wheels, frame - generally speaking.
4/ common sense prevails - if not we would be all still using Avon Scramble tyres and Doherty grips - its a leading question what's your point
5/ its VMX not a roadworthy.
Greg
If everything proposed got up the book would be a telephone book so lets look at the question of what parts you feel should be replicas - post some images and lets look at it.
I have the submission in front of me, happy to discuss it in detail if you want to outline however the reference and any reference to the Evo class as noted in the submission will be ignored.
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Thanks Dave I guess most people would assume all of those things you have listed and that was my assumption also. As I said this is not meant to take this thread into a mess as that does no one any good.
I just think that definitions of critical terms would make reading the rest of the rules much clearer and would remove almost all assumptions out of the equation.
I completely agree that every proposal cannot ‘get up’. It is just that it seems the objectives of some proposals appear to have merit but the proposal is either incomplete or badly worded and is rejected completely. Maybe the Commission cannot alter a proposal and that is the reason I am not sure.
As I said this is not meant to take a valid thread into another augment that benefits no one. My suggestion was trying to offer a possible solution as I think that the Maico backing plates are a glaring safety area and the billet backing plates offer a good solution. The rules are not clear if they are OK or not. If a definition of replica/representative part were in the rules no one would be in any doubt.
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another thread going to evo class AGAIN
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Greg, it's extremely difficult to cover all contingencies, and often the more rules one introduces to plug holes the more leaks get sprung elsewhere.
It gets complicated when individual vested interests come into play.
The biggest complication is we have hoomen beans involved.
It would be great to have clear definitions, but often if applied literally and acurately, create far greater problems than they avoid.
An example is some years ago, a beautifull bike was put together totally within the rules of the day, and a small number of people decided it wasn't kosher by their judgement. Every argument was dredged up by a vocal few, although the vast majority were happy about the bike. Letters were received by international riders of the day,and the current organiser of the class that included this bike who ran huge international meetings. The bike would be accepted at those big meetings, which we had in writing, but none of this evidence swayed the objectors. After having all the arguments answered suggesting by any fair reasoning the bike was kosher, they finally fell back on the definition of replica. I found three varying definitions in different dictionaries, two of which suggested a degree of flexibility but the third stated a replica was an EXACT FACSIMILE of the original. Guess which one was chosen. The bike disappeared for many years as it couldn't be proven the component was an EXACT to the nth degree copy under the chosen definition.
Sorry about the long winded story, but I think we need to be very carefull we dont create more problems than we cure.
The more definitions we introduce the less scope for common sence we have. Therein lies the dilemna.
At the end of the day, some official, committee, board or courtroom has to make a judgement call on something no matter how tight the rules.
There are some good suggestions being aired on here, but already we are seeing, hang on if that happens my super doopa poopa scoopa might be in question; the billet safety component i just spent a fortune on isn't listed; etc etc. Some poor bastard or committee will have to rule on it using, guess what, common sence.
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Greg
You asked the question what are major components. The Historic Road Race GCRs define them.
16.12.0.3 Major components are:
a) All engine and gearbox external castings,
b) Frames,
c) Swingarms,
d) Brakes,
e) Forks and fork yokes.
16.12.0.4 All other components shall be considered as minor components.
Kevin
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Common sense is no friend to a book of rules in my experience . You can have one or the other or guidelines and common sense . As soon as you set out rules you have to accompany them with crystal clear definitions or you leave it wide open of missinterpretation, manipulation and exploitation from both competitors looking for an edge and officials with an axe to grind . Common sense is great when it suits and what most of us were raised with in the pre PC world.
However nowadays if you want a set of rules you have to cover all bases,you cant get half pregnant . Alternativley have loose guidelines and self governance with no judicial system.
Its not a perfect world and at the end of the day we participate in a very minor part of a very minor global pastime ( motorsport ) and could it be we take ourselves to seriously ???
I take the point that to make what seems a simple amendment for the greater good to a rule , can lead to a catastrophic sequence of events further down the track.
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Greg, it's extremely difficult to cover all contingencies, and often the more rules one introduces to plug holes the more leaks get sprung elsewhere.
It gets complicated when individual vested interests come into play.
The biggest complication is we have hoomen beans involved.
It would be great to have clear definitions, but often if applied literally and acurately, create far greater problems than they avoid.
An example is some years ago, a beautifull bike was put together totally within the rules of the day, and a small number of people decided it wasn't kosher by their judgement. Every argument was dredged up by a vocal few, although the vast majority were happy about the bike. Letters were received by international riders of the day,and the current organiser of the class that included this bike who ran huge international meetings. The bike would be accepted at those big meetings, which we had in writing, but none of this evidence swayed the objectors. After having all the arguments answered suggesting by any fair reasoning the bike was kosher, they finally fell back on the definition of replica. I found three varying definitions in different dictionaries, two of which suggested a degree of flexibility but the third stated a replica was an EXACT FACSIMILE of the original. Guess which one was chosen. The bike disappeared for many years as it couldn't be proven the component was an EXACT to the nth degree copy under the chosen definition.
Sorry about the long winded story, but I think we need to be very carefull we dont create more problems than we cure.
The more definitions we introduce the less scope for common sence we have. Therein lies the dilemna.
At the end of the day, some official, committee, board or courtroom has to make a judgement call on something no matter how tight the rules.
There are some good suggestions being aired on here, but already we are seeing, hang on if that happens my super doopa poopa scoopa might be in question; the billet safety component i just spent a fortune on isn't listed; etc etc. Some poor bastard or committee will have to rule on it using, guess what, common sence.
Col, you can have many and varied definitions of a word. One definition of replica is a miniture scale exact duplicate or words to that effect.
That is why our rules should contain a (our) definition of important issues such as what is major component, what is a replica
Yes there will still be disputes, as you say human beings are involved. Trying to minimise the these disputes surely would be a good thing.
The reasoning that we may not be able to make the definition clauses absolutely perfect in every possible or conceivable situation or that someone may still find a way to protest does not seem to be a strong reason to avoid it completely. These definitions were in the rules in a fashion until 2009 from memory.
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Greg
You asked the question what are major components. The Historic Road Race GCRs define them.
16.12.0.3 Major components are:
a) All engine and gearbox external castings,
b) Frames,
c) Swingarms,
d) Brakes,
e) Forks and fork yokes.
16.12.0.4 All other components shall be considered as minor components.
Kevin
Yes I know.
Not commenting further as Graeme has asked this type of discussion, even though this one seems to be civil and productive, should be in the newly created area of the forum.
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Yes you are right. Graeme said he would move threads if he thought they should be in the new section. Maybe it is time for it to move.
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with an understanding of where HRR is at in Australia right now, please lets not travel that path as if you think there are issues in VMX flip over to HRR to see just how it can all go south.
There is always the reasonable person test. I accept that a reasonable person would consider a safety issue like the Maico brake thing as a given. Same goes for many things that are similar in nature. Considering what we can add to the rules to tighten it up forgets that by in large there are no problems - certainly by comparison to HRR (just my opinion). In my experience you say more with less words.
The text Kevin has added is verbatim to MNSW submission for CMX - only the numbers changed from HRR.
On another note - while not agreeing with the eligibility proposal MNSW put forward the age class for pre 85 as well as the alterations to the slider class both did. (MNSW Proposals) it now rests with the states to decide the outcomes.
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If we are happy with "the vibe of the thing", then we should follow NZ's lead and ditch the rule book altogether.
Otherwise, we need rules that are clear, concise and understood.
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on the replica thing as well. In the past the view of what a replica could be was determined by the radius of a frame bend or the angle of a guset. I would strongly argue that if we are going to define what replica means then we are going to head down a rocky road that hasn't considered history.
There is already an understanding that they don't make historic bikes anymore so if we are going to keep using them then things should be done - a good example is the flexibility given to frames in pre 60 and pre65 - this been done to encourage people to build a machine without being scared to death that someone would argue that in 1964 the frame had a lug here rather than there. Surprises me that GMC hasn't made a production Tribsa replica frame kit yet..........
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If we are happy with "the vibe of the thing", then we should follow NZ's lead and ditch the rule book altogether.
Otherwise, we need rules that are clear, concise and understood.
I don't disagree however in my past experience in sailing where everything was so well defined you needed to take your lawyer into a protest with you - and some did.
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Ok... Getting back on to the original topic:
What magnesium parts have a history of breaking AND don't have cheap, commonly available era-correct alternatives?
It is just the Maico brake plates, right?
Surely the worst solution is to make an allowance for Maico brake plates?
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As someone said else where don't call something a replica use the word representation of a part/component.
Also NZ haven't got a rule book but they also haven't got a controlling body. They run non sanctioned. I don't know if the majority of us want to go down that route. Some may.
Just because Historic Road Race may have problems doesn't mean everything they have is no good.
Nathan
Sometimes making rules is like preventative maintenance. You don't wait for something to break before you replace it. If you know magnesium has a life you make allowances to replace it before it is a problem.
Kevin
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Fair call, but we all live under the cloud of fatigue on old components.
If there's a demonstrated or reasonably expected weakness, then it should be addressed - but the thousands of Yamaha magnesium brake plates that have zero issues show that simply being made of an Mg alloy doesn't automatically guarantee failure.
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with an understanding of where HRR is at in Australia right now, please lets not travel that path as if you think there are issues in VMX flip over to HRR to see just how it can all go south.
No idea about HRR but I can't see how defining major parts can cause problems
Seems to me it can only solve issues.
Replica, representation, likeness, carbon copy, call it what you like but why was it removed from the book??
If all alterations have to be submitted and approved then who submitted that this rule should be removed and for what reason?
And who approved it for what reason?
Don't know why people are getting hung up on billet parts either, whats it matter how the part was replicated, cast, machined, 3D printed or beaten over an anvil if its a close copy then it should be fine.
You may not like shiny billet but I don't like black rims and that doesn't mean they should be banned.
Rules shouldn't be about personal taste.
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the thousands of Yamaha magnesium brake plates that have zero issues show that simply being made of an Mg alloy doesn't automatically guarantee failure.
Oils aint oils
Aluminium has many different grades. The grades are made up of differing amounts of several elements which produce different attributes.
Mag is much the same, not sure how casting Mag is graded but different companies doing different pours would have their own batch formula that they would work to.
Having welded many different castings over the years I can tell you that not all Mag welds the same.
Some are high content Mag and some are low.
Then you also get aluminium that has a low mag content.
It doesn't surprise me that different mag castings from different companies behaves differently at all.
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theres not much i cant cast in alumium backing plates for brakes ezey but will it be strong with out heat treating i dont know
I would say it would need to be heat treated but I guess it would depend what grade alloy you use.
The heat treaters I take my parts to always has batches of castings being done.
I think also machinists prefer parts to be tempered to make machining easier, soft alloy tends to drag under the tooling
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Surprises me that GMC hasn't made a production Tribsa replica frame kit yet..........
Not through any lack of want but to set up for a frame takes a lot of hours to get everything right. As well as the actual building of the jig I need to get all the templates right which can often need fine tuning, then there's the detailing of all parts and assembly so it can be done time after time without them all being like snowflakes ( no 2 alike)
Research also needs to be done on all motor and wheel options so everything can fall together smoothly for the builder.
Would love to have the time for more R & D as I have lots of ideas bouncing around inside my head but just don't have the time to set them up.
Last frame I jigged took the best part of a month to get all the details correct.
Just set up for another airbox, that took the best part of a week, I can only justify the time spent by hoping I can sell more units in the future, and in between setting up comes all the boring production work that pays the bills.
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And a client wants more modern footpegs and some mods for stroker cranks and wider back tyres and???
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it takes me 4 weeks to get rooted clutch cover to a finished one with patten makeing casting jigs programing
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Thanks Geoff for your clear carefully considered posts.
In the past rules have just disappeared when MA do a re-write of rules. I think this is what occurred with the rule from 2009 disappearing. If there was a proposal to take it out it should have appeared in the 2010 MOMS with a strike out. Hopefully now that it has been pointed out that it has disappeared it will be corrected.
Again you are correct re aluminium when you buy billet alloy there is different grades. Anyone making parts that are under stress would need to ensure they used the correct grade. Also I spoke to John Titman yesterday and asked him when did Talon start making hubs for MX. He said they were making hubs for speedway in the 70s and probably started making them for MX in the 80s. I'll try to get the exact facts.
Just so everyone knows CNC machines have been around for years. I was working for a company that had CNC lathes and a machine centre in 1980.
Kevin
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Thanks Geoff for your clear carefully considered posts.
In the past rules have just disappeared when MA do a re-write of rules. I think this is what occurred with the rule from 2009 disappearing. If there was a proposal to take it out it should have appeared in the 2010 MOMS with a strike out. Hopefully now that it has been pointed out that it has disappeared it will be corrected.
Again you are correct re aluminium when you buy billet alloy there is different grades. Anyone making parts that are under stress would need to ensure they used the correct grade. Also I spoke to John Titman yesterday and asked him when did Talon start making hubs for MX. He said they were making hubs for speedway in the 70s and probably started making them for MX in the 80s. I'll try to get the exact facts.
Just so everyone knows CNC machines have been around for years. I was working for a company that had CNC lathes and a machine centre in 1980.
Kevin
If your thinking about getting Maico rear hub CNC made have you any idea how much it would even cost for the piece of billet you would need to start with let alone the machine time. Then it would need the cast drum installed. My guess would be around $1500 per hub.
Also if CNC's have been around for that long show us a picture or magazine add from 1981 or 2 of the billet Maico backing plates that could be purchased at that time.
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If your thinking about getting Maico rear hub CNC made have you any idea how much it would even cost for the piece of billet you would need to start with let alone the machine time. Then it would need the cast drum installed. My guess would be around $1500 per hub.
Also if CNC's have been around for that long show us a picture or magazine add from 1981 or 2 of the billet Maico backing plates that could be purchased at that time.
Yes I have got a good idea how much it would cost to make a CNC rear hub. If you want to pay that much great I'll make you one. But if I wanted one I would only pay 290.00 euro plus postage. Also you don't need to get the braking surfaced casted, it could either be sprayed into place or machine a ring and shrink fit it and probably pin it as well. I didn't say the parts were made in 1981.
The facts are continuing to use old parts for race bikes is a ticking timebomb. All forms of Historic/Classic motorsport recognise this.
Also if I was going to make a CNC rear hub I would make more than one. The main cost is in the programing and the setup.
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In theory, CMC machines can't do anything that a skilled machinist can do.
Certainly the difference between a set of Kelvin Franks' triple clamps and a set of CNC'd triples is minimal.
The big advantage that CNC has is that the price per component drops rapidly over a production run, making "custom" bling parts a lot more accessible than hand made parts.
I'm really not a fan of CNC'd bling on old bikes, but it would have been possible to build a billet Maico brake plate in 1960, if anyone had bothered.
Personally, I would like to see brake plates be restricted to period parts or accurate replicas EXCEPT we have a demonstrated safety issue on Hitler's Revenge, so there needs to be some additional freedom.
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Problem at the moment with the current rules those backing plates aren't legal as even though they claim to be replicas even a blind man could tell the difference. So you will just have to park up your bike until the rules can be changed to allow them. You could of coarse grind off all the machining mark and then sand blast them to make them look like cast pieces.
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Billet triples and lower fork legs were around in the 70's early 80's so it would've been possible to make anything billet alloy I'd think...
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My bike passed eligibility scrutineering at Toowoomba so it is legal.
Nathan, Adolf did race a Maico he almost won the World Championships a couple of times.
Adolf Weil of course. The AW Maico is named after him. He died earlier this year he really was a great motocrosser. RIP
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Billet triples and lower fork legs were around in the 70's early 80's so it would've been possible to make anything billet alloy I'd think...
And lets not forget about all the titanium bits and pieces that adorned most top level bikes.
I think it would be unjust to allow billet parts on one brand of machine and not another. A lot of hubs, brake plates and various other parts get worn beyond being use-able safe condition over the years, regardless of manufacturer.
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I am not an expert in this field, but what would one gain from having billet wheel hub with bolt/rivet(CZ hubs) in brake liner that is an exact copy of the original (aluminium,magnesium, worn out)cast one. I can only think of the wheel hub being safer, maybe a touch stronger and heavier depends on what material is used. And i am prety sure that there was a lot of sand cast/billet hubs and parts on works bikes in 70'and 80'. And let just be honest. One dont have to have a CNC machine to make an old school wheel hub lads. Old school lathe, bench drill and bit of thinking would be enough to make most of hubs that dont use straight pull spokes.