Magnesium

[Nathan S]

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?

[KTM47]

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

[Nathan S]

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.

[GMC]

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.

[GMC]

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.

[GMC]

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

[GMC]

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.

[SON]

And a client wants more modern footpegs and some mods for stroker cranks and wider back tyres and???

[kdx 175]

it takes me 4 weeks to get rooted clutch cover to a finished one with patten makeing casting  jigs programing

[KTM47]

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

[sleepy]

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.

[KTM47]

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. 

[Nathan S]

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.

[sleepy]

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.

[JohnnyO]

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...