Author Topic: YZ360B  (Read 17973 times)

0 Members and 1 Guest are viewing this topic.

firko

  • Guest
Re: YZ360B
« Reply #30 on: April 27, 2010, 10:19:47 am »
Quote
Firko DONT take this the wrong way  arenth they suppost to be pre 70, and look like the model they are representing from the outside...
.
You're spot on Freaky. If rule 16.6.0.1 states "Engines must remain externally unchanged", was to interpreted literally, the RT1 engine in my Cheney would be ilegal. The sidecovers, head, and inlet system would deem it to be "externally changed". However, if the rule was to interpeted literally anybody with a DG head, aftermarket external cases, or other mods could be challenged by officials.

To make things even more difficult for me, I'm the guy that authored that particular rule twenty odd years ago, which makes me a bit of a hypocrite in some peoples eyes :-\. However, I reckon that precedent must come into it. I raced my DT1 Yamaha in pre '70 competition for about 10 years ,collecting some trophies at National level along the way using the very same cases and it was never, ever challenged in scrutineering. In fact, nobody even commented on them to my recollection. Using that as a precedent, I fitted DT2MX outer cases to my engine purely because I like the look. The cases offer no performance enhancement and any performance increase from the head would be pretty dubious. I've used it purely so that I can route the pipe through the airbox as the factory intended. As the Cheney factory never made an RT1 powered machine, sticking to the 250cc DT1 engine and modifying a GYT head to allow the pipe at the factory, I'm stuck with finding something suitable and at present, it's the ACK head. As I wrote in an earlier post, I don't particularly like the ACK radial head as it looks too modern(to me anyway). A Webco or even better an RT2MX head would be more in fitting with the period look even if they too are from outside the pre '70 era. It's best we remember here that the RT1 engine itself wasn't released until mid 1970 which makes the whole what's in, whats out argument a little weird considering the class is pre '70.

As someone with strong feelings about "period integrity" I fully understand your points Freaky and I'll be running the bike past Dave Tanner at CD7. If Dave or any other official thinks that I've gone too far with those cases, I'll be more than willing to fit original RT1 cases in time for the Dirt Track Nats  with no argument. I've only fitted those cases because they 'look cool' and have tried to build a bike that I would have built in 1971 if I had been cashed up. Everything elses on the bike is is totally within period except for the rear backing plate which I haven't made my mind up on yet anyway.

Offline vmx42

  • Legend
  • *****
  • Posts: 1579
    • View Profile
Re: YZ360B
« Reply #31 on: April 27, 2010, 11:54:28 am »
Quote
Firko DONT take this the wrong way  arenth they suppost to be pre 70, and look like the model they are representing from the outside...
.
You're spot on Freaky. If rule 16.6.0.1 states "Engines must remain externally unchanged", was to interpreted literally, the RT1 engine in my Cheney would be ilegal. The sidecovers, head, and inlet system would deem it to be "externally changed". However, if the rule was to interpeted literally anybody with a DG head, aftermarket external cases, or other mods could be challenged by officials.

To make things even more difficult for me, I'm the guy that authored that particular rule twenty odd years ago, which makes me a bit of a hypocrite in some peoples eyes :-\. However, I reckon that precedent must come into it. I raced my DT1 Yamaha in pre '70 competition for about 10 years ,collecting some trophies at National level along the way using the very same cases and it was never, ever challenged in scrutineering. In fact, nobody even commented on them to my recollection. Using that as a precedent, I fitted DT2MX outer cases to my engine purely because I like the look. The cases offer no performance enhancement and any performance increase from the head would be pretty dubious. I've used it purely so that I can route the pipe through the airbox as the factory intended. As the Cheney factory never made an RT1 powered machine, sticking to the 250cc DT1 engine and modifying a GYT head to allow the pipe at the factory, I'm stuck with finding something suitable and at present, it's the ACK head. As I wrote in an earlier post, I don't particularly like the ACK radial head as it looks too modern(to me anyway). A Webco or even better an RT2MX head would be more in fitting with the period look even if they too are from outside the pre '70 era. It's best we remember here that the RT1 engine itself wasn't released until mid 1970 which makes the whole what's in, whats out argument a little weird considering the class is pre '70.

As someone with strong feelings about "period integrity" I fully understand your points Freaky and I'll be running the bike past Dave Tanner at CD7. If Dave or any other official thinks that I've gone too far with those cases, I'll be more than willing to fit original RT1 cases in time for the Dirt Track Nats  with no argument. I've only fitted those cases because they 'look cool' and have tried to build a bike that I would have built in 1971 if I had been cashed up. Everything elses on the bike is is totally within period except for the rear backing plate which I haven't made my mind up on yet anyway.

Who cares, it looks great [almost as good as a Dutch Twinshocker]!  ;D
When a woman says "What?", it's not because she didn't hear you, she's giving you the chance to chance to change what you said.

Beam me up Scotty, no intelligent life down hereā€¦

"everyone is entitled to their own opinion, but not to their own facts"

firko

  • Guest
Re: YZ360B
« Reply #32 on: April 27, 2010, 01:20:16 pm »
Quote
Who cares, it looks great [almost as good as a Dutch Twinshocker]!
Smart arse ;D
I reckon it looks better than standard but Freaksters got a point. I'f I'm going to waffle on about others "getting it wrong" I've got to cop it back occasionally. To be honest, the bike's only going to see a few proper meetings a year, both Nats with a mate riding and the odd dirt track or two with me at the helm so if I have to change the covers over for the Nats events, that's what I'll do. For CD and HBBB action, who gives a shit!

Anyway...I best get back back to the shed or the bike won't even make it to CD7.

Offline Freakshow

  • Superstar
  • ******
  • Posts: 7277
  • Adelaide, SA - looking for a "YZA" tank
    • View Profile
Re: YZ360B
« Reply #33 on: April 27, 2010, 01:54:09 pm »
Quote
Who cares, it looks great [almost as good as a Dutch Twinshocker]!
Smart arse ;D
I reckon it looks better than standard but Freaksters got a point. I'f I'm going to waffle on about others "getting it wrong" I've got to cop it back occasionally. To be honest, the bike's only going to see a few proper meetings a year, both Nats with a mate riding and the odd dirt track or two with me at the helm so if I have to change the covers over for the Nats events, that's what I'll do. For CD and HBBB action, who gives a shit!

Anyway...I best get back back to the shed or the bike won't even make it to CD7.

Yer im just mindful of how we jump up and down over period correct from the outside, and you have to draw a line somewhere, i think with the correct side covers you should be fine, internals are free so that doesnt come into it, but where do you draw the line on other bits added out of period and when does it become a part or not ??

IM just playing the devils advocate.  IF its 'the bike you would have built in 1971'  if you had the cash,  cool what a great progect to get into and how you want it, but its still a pre 75 bike  and would be just as competiditive so why put it in a period before it could have been ? 

all that does is blurr the lines even further and then everyone takes a bit more.  PAtterson had that PRe 75 MX 250 on the line at the canberra nats and his excuse and precedent was my dad road it back in the day. not entirely true for that model engine and thats fine but thats the issue is its a 1975 model end of story and the rule is in place for a reason.

Not that its going to effect me any , but i think fair is being consitant and its perhaps not the bike itself, but its the precedent it then sets for other to mold the rules 'cause they like to have built it like that' - when they (insert period here) had the cash if they rode in the time. 

I'D just like to see it with the right Side covers on it, if it was on the national stage and the other stuff spec back so it looked like the period it is representing, after all its as much about the spectical as the racing and Jo public has the right to see what looked correct.    Once the door gets too wide open, we have a dutch class.

Rubber bars, shocks etc etc the line is clear and we have to be consitant.  on a national stage it needs to look like its right like we have all agreed, from the outside, on the inside you can cut in a 09 YZ250 in there for all it matters, ( hell the Period RR guys do)  but if we dont get the outside route right ,everything else is just build on a falacy.

PRecedents are dangerous as they just keep getting moved around like statistics.

Im glad you can see im genuine and not being a dick, but i really like the fact that Vmx seems in the whole, to present period machinery like a working museum,  thats what id like to see on the track, other wise it will be Blue/purple sx rims, FAt snail pipes, gripper seats, anodised shocks and forks, plastic tanks on em before you know it and the pre 75 looking bike is long gone.............. and then whats the point.
« Last Edit: April 27, 2010, 02:00:57 pm by Freakshow »
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

firko

  • Guest
Re: YZ360B
« Reply #34 on: April 27, 2010, 03:43:30 pm »
I agree with everything you say. Absolutely everything. The whole heart of our sport revolves around us maintaining the period integrity of the bikes we race. For years I've been ranting on about bikes that miss out because their owners fail to see the cutoff point between eras. Now here I am fudging the calendar myself. I got lost in the same red mist that produces great bikes that are ruined by inappropriate out of period parts like wave disc rotors on a certain CR500, Excel rims on pre '75 bikes, alloy swingarms with no historic precedent and all the other stuff I've whinged about for years. If I'm expecting to be taken seriously when I do whinge about such stuff, I should be setting an example with my own bikes.
The conical front hub and alloy rear hub are being replaced on my Maico so it's only right that the Cheney be right as well. The Cheney to my mind is 100% pre '70 legal except for the side covers and head but I'll still go over it with Dave over a beer ay CD7.   

There's a pre '75 Hindall framed version of the same bike coming up before long so the side covers and head will find a happy home on it.
Quote
IM just playing the devils advocate.  IF its 'the bike you would have built in 1971'  if you had the cash,  cool what a great progect to get into and how you want it, but its still a pre 75 bike  and would be just as competiditive so why put it in a period before it could have been ? 
The frame was made in 1969 by Eric Cheney, the engine is a piston port RT1 and therefore pre '70 legal, the forks and wheels are all period so it's a legal pre '70 bike. I should have written...the bike I would have liked to build in 1969 if I was cashed up.
« Last Edit: April 27, 2010, 03:53:21 pm by firko »

Offline tony27

  • Legend
  • *****
  • Posts: 1908
    • View Profile
Re: YZ360B
« Reply #35 on: April 27, 2010, 05:49:05 pm »
How many people not heavily into yamahas would know that the side covers aren't pre 70? Does seem a little pedantic to me

Offline Freakshow

  • Superstar
  • ******
  • Posts: 7277
  • Adelaide, SA - looking for a "YZA" tank
    • View Profile
Re: YZ360B
« Reply #36 on: April 27, 2010, 08:02:53 pm »
good on you for being open to debate and understanding its a discussion about what rather than personal stick.   Sorry tony its not about whether you know its a 72 clutch set up or not, its the point of showcasing a period.  we either do or we dont, you keep greying the lines it just gets so blurred you end up with a pre 85 class.  to be honest i have run the Dt2mx case on a DT1 and it actual seems to work beter, mabye the button has a better cable angle, or my Dt1 buttons are all routed but it did seem a better unit on the bike, so you could agure although it works the same, does it really ?? the next debat is as these unit shit themselves , i havent seen many new or remade nylon buttons ( still cant believe that - be a fortune in it for someone) so what next ?  to keep the bikes running how do you make someting like the speedway actuator look period ? legal but nothing like the cover are they, there is probally a lsit of extenal consumable parts we need to master while keeping them period looking i think.

Im just throwing out the idea that its not perhaps about the mechanicals of our bikes thats important, most punters wouldnt under stand an omniphase balancer, but to see a row of YZA with DT1 cover on them kinda does the class a diservice, how do you preserve the integrety of the class by "trying" to let people comply with and maintaining a racing bike, in both ease of ongoing performace but also looking like it should rather than a poisin lil abomination, that just makes the sport only that, it visually represent nothing.

74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

Offline Freakshow

  • Superstar
  • ******
  • Posts: 7277
  • Adelaide, SA - looking for a "YZA" tank
    • View Profile
Re: YZ360B
« Reply #37 on: April 27, 2010, 08:05:26 pm »
PS dave tanners on MAster chef again right now .....so , ill be back in a minute after i seen what tanner is cooking tonight
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

Offline Rossvickicampbell

  • Legend
  • *****
  • Posts: 3779
    • View Profile
Re: YZ360B
« Reply #38 on: April 27, 2010, 08:28:22 pm »
and Freaky  -just to stray a little further - what about rare parts - what about YZB clutch actuator covers that are at $500USD and rarer than hens teeth.  What you have said is correct but what about when things are no longer available?  What about being able to put a 2010 Ohlins shock on a get away with it?  I am all for it - accuracy that is - but it is not an indefinite proposition?

Rossco
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline Freakshow

  • Superstar
  • ******
  • Posts: 7277
  • Adelaide, SA - looking for a "YZA" tank
    • View Profile
Re: YZ360B
« Reply #39 on: April 27, 2010, 09:01:25 pm »
YEp thats what im saying above, its a conumdrum.  how do we keep the external and also keep them on the track, in firkos case it easy when a DT1 cover is easy to get he period correct, and  the YZ mags well i got 3 on the shelf here, but like you thats where they sit and im using cut up Dt1 covers, but whats the story with the buttons? if we cant get someone to remake them how do you keep em going and keep them looking "right on the outside"

i want them to look right from the outside and dont care about the inside, so there my gut feel is, lets keep it looking right, but get smarter in how we build the bits to keep em running under the skins.

My point was really lets try to hang onto what we can, i can reason with sympethtic looing modern shocks Im not sure the ohlin piggies have the short travel shock so thats ok be few and far under exsisting rules, but more so limit Bling to actual period or consumable parts, stuff thats small or cant be sourced otherwise, and where posible at least looks period in style. 

Just i hate to see us get lasy and run with the anodised rims, forks, shocks, grippers, later covers etc etc. cause its easy, get em in black or silver at least, be nice to Keep the period stuff for as long as we can and that way they at least look a bike were trying to  recreate, otherwise it may as well look like a row of modern bikes, other thqan the colour who would know the model....

Guess its like keeping your kids , kids but it would be nice to keep it as long as we can, and trying to make them look like they did where we can if its just the simple stuff like the covers.  :D
« Last Edit: April 27, 2010, 09:17:36 pm by Freakshow »
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

Offline DJRacing

  • Legend
  • *****
  • Posts: 1598
  • YZ125X
    • View Profile
Re: YZ360B
« Reply #40 on: April 28, 2010, 05:11:38 pm »


isnt that clutch mech great.

Freaky, Rossvickicampbell, that is the reason why the guy made the clutch actuator.

The internals (worm gear etc) from old road bikes are steel not plastic like the YZ's so he has made the housing to look like the YZ-A/B and modified it to fit the yamaha XS road bike's worm drive parts which are still available at reasonable cost. The worm drive from the road bike lasts longer and as you can see the whole thing looks great. It wouldnt be that hard to drill a couple of holes on the inside (top and bottom) so that they cant be seen, tap a thread into each and then make up a nice ali spocket cover. That way you can remove it and not have any threaded holes showing so you still have the YZ look and when needed, just bolt the spocket cover on and go racing.
If at first you dont succeed, give up and drink beer

Offline tony27

  • Legend
  • *****
  • Posts: 1908
    • View Profile
Re: YZ360B
« Reply #41 on: April 28, 2010, 06:36:48 pm »
You could have a career in sales & marketing there DJ ;D

Offline Marc.com

  • Legend
  • *****
  • Posts: 3887
    • View Profile
Re: YZ360B
« Reply #42 on: April 28, 2010, 07:11:15 pm »
Quote
However, if the rule was to interpeted literally anybody with a DG head, aftermarket external cases, or other mods could be challenged by officials.

hell if it was taken literally we would be all riding boring as batshit stockbikes and the period trick bits that I live for would be down the river.

Funny you mentioned the classic road race guys changing internals, recent article in Classic Racer refered to modern Manx Nortons as 'Supermono racing"  ;D, But their presence has certainly lifted the profile of RR and meant Patons and other repro exotica were built to beat them. Maybe a few B50 motors with YZ450 internals wouldn't go amiss.
formerly Marc.com

Offline Rossvickicampbell

  • Legend
  • *****
  • Posts: 3779
    • View Profile
Re: YZ360B
« Reply #43 on: April 28, 2010, 10:16:16 pm »
Yeah DJ - we must be a bit slow on this side of the pond.  Mate and I just found the XS etc worm drives - at a much better price also.  Gary has access to an engineering shop so he went through the trial and error path of getting one made up that fits the original cover etc.  Must admit his clutch actually feels a little lighter than mine - dont know whether the additional spiral on the worm drive helps but he has been out and about on it a couple of times now with no problems.  All for less than $50Aus whereas the genuine plastic unit pulls around $150USD now.

So well done to the man in question above.

Rossco
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline Freakshow

  • Superstar
  • ******
  • Posts: 7277
  • Adelaide, SA - looking for a "YZA" tank
    • View Profile
Re: YZ360B
« Reply #44 on: April 28, 2010, 11:33:03 pm »
At the nats i saw Tony herb bike and son adam had cast a whole new cover and they drmelled it to take a xs 650 worm.

I guess it all posible if you know what your doing the rest of us i guess will just have to keep turning up the the day job to pay for it all......
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff