1992 Supercross protest from Yamaha against Honda-92' CR250 swingarm

mofomotojoe
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4/27/2020 7:21pm Edited Date/Time 5/1/2020 2:02am
I have written Pulpmx about this but did not get any answer.
Now that it is ancient history. All our childhood heroes spilling some beans.... On Pulpmx, on Whisky Throttle,
..etc.. GL opening more and more on how they got a few bikes at a specific dealer to get the " homologation" etc.. big bores reveal, etc...

Is it safe to come out clean? Can Dave Arnold, Cliff White, anybody can come clean on this?

At the beginning of the 1992 season, JMB and Stanton struggled with the brand new CR250.
New chassis, engine.. while they had the previous model well fine-tuned from 1989-1990-1991
Bayle and Stanton started winning again mid season.

The official word is that Mc Carthy and Yamaha US filed a complaint against the honda team, saying their frame and swingarms were illegal.
Production rule states that the machines must race with production frame and swingarms . these can be modified, material added, but they must start with the production items.

watching videos on the the vault and yutube. the word from Art and Larry is that Bayle and Stanton's CR250R were impounded and it took several days for the AMA to measure the frames and swingarms, which were found to be legal.

Any documentation on this? possible some Benjamins were exchanged and some wheels were greased?
Who worked at the AMA and can today standup and honestly can confirm this? any pics? where is this documented?

Here are my observations and why it bothers me:

I have owned, raced and serviced the 1992, 1993 and 1994 CR250Rs

While looking at all the pictures from Bayle and Stanton's 92' machines,
their swingarms look inconsistent. Proportions and the upper edge varies.
look at the light how it bounces on the upper corners. since the rectangle parts are extrusions, the radii would only vary if the thickness was different. At times the upper outer corner edges highlights are thin, then other times they are much wider, showing a larger radii. Even if you polish the swingarms, a massive amount of material would have to be removed to have this effect.
I swear on some pictures the proportions are fishy. I have owned these bikes and spent long hours gazing at them, almost to a Michael Lindsay level, so I am telling you something is bothering me.

I have been collecting pics and will post these to showcase this.

Further, on the left side of the frame, the swingarm pivot section is MASSIVE on Bayle and Stanton's bikes.
it is always hidden by the aluminium frame guard triangle part, but insome youtube videos where Stanton's mechanic is swapping the shock, the guard is removed. I freezed the frame and you can clearly see that the pivot area is a giant box, while the stock bike has a skeletal twig wrapping around with ample clearance from the front sprocket guard.
Another pic on Dave Arnold in the shop where JMB's bike is being worked on without the guard. Again, the frame shows this massive boxed section.

The frame mod does not bother me. I can understand it was beefed up.
But the swingarm... I have a feeling that these are not mods of the stock ones.

Several shots from JMB and Stanton, even MC Grath whipping their CR250s and the underside of their swingarms greatly varies. Sometimes a long reinforcement is welded underneath, sometimes the cast piece itself looks different, other times the overlap where the cast piece is welded to the extruded spars ... are very different. doubt that they cut the swingarms and rewelded them after shaping new cast pieces. the junction at time has a long inner edge which the stock swingarm does not have. I know, I have bought used CRs with drilled swingarms for sidestand so I have a good guess where the cast piece ends in the inside.
The rear ends, the machined ends which hold the sliding blocks holding the rear axle... also seem to my eye to have different taper, thickness and likely material as well.
on the stock 92, the sliding block would rock and start chewing the swingarm end everytime you tighten the rear axle. Even with a tighter machined sliding block, there is not enough upper surface holding the sliding block and once you move the block halfway back, half of its upper edge is exposed.
I saw how Honda USA did it with a deeper, flatter axle block but still, the rear of the swingarm, although looking like a sibbling of the stocker, has different angles, thicknesses to me.

Okay this has been bothering me for over a decade now. Quarantine blues and lack of pulpmx involvement... I am now resorting to the finest: You noble sires on vital.

My experience with the 1992 model, I hated the chassis and it swapped a lot. I loved my 94 but am now owning a 93 which I keep for the memories and occasional vintage ride, I love it but the rear end has never been as confidence inspiring as my Suzuki RMs , YZs of similar years.
Either dirt bike or MXA published an article in 1993 showing how to mod your 1992 CR250 frame and swingarm with input from DeCoster.
" if it worked for JMB and Stanton it's good enough for you"
They showed how to box the left side swingarm pivot on the frame, beef the backbone,
and recommended welding L shape 1/8" plates under the swingarm. I have never seem these exact mods on stanton and Bayle's bike, exept for a single pic of Stanton where an obvious plate has been welded under the inner bottom edge. ( 1992 finale where he comes in the turn )

if you place the 92, 93, 94 and 96 bare frame next to each other, it is quite interesting.
the 94 has multiple gussets, reinforcements, quite extensive little add-ons compared to the 92.
I cannot tell the difference between the 92 and 93 since I sold the 92.

Anyway. I love our times where all these podcasts are shedding light on these events.
I would appreciate if anybody has any information on this. No hate, just let's come out clean.
Stanton and JMB were baddasses and if their team bent the rules this does not deter in any way my respect.
It's also cool if the recipes of the past can be disclosed..

Will upload pics some time
Cheers



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USA
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4/28/2020 5:18am
Interesting story, looking forward to the pics.

Idk how you tell that level of detail from such old and grainy footage, did you find some super secret HD repository? Laughing

You're almost there though, you've done a ton of the research I believe a journalist might do for discovery. Keep it up and you might find the answer..
The Sneak
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4/28/2020 5:30am
Didn't Honda bitch about Bradshaw's WR500 bc it was running a YZ250 swingarm?
Seems like Honda and Yamaha had some on and off beef over the years. I believe Kenny Clark told them at the start of '86 something along the lines of 'you won't be shit without your works bikes'.
Oops.
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sandman768
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4/28/2020 6:07am
It’s only cheating if you get caught.....
DynoDan22
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4/28/2020 7:04am
My friend had a '92 CR250 and the frame was very flexy. lol I was sitting on it on day while the bike was on the stand and I could flex the frame by gripping the frame with my legs (squeezing the bike) and applying a side load to the bars. I immediately thought the backbone of the frame was broken. I convinced him to take the seat and tank off to inspect it. Nope....frame was fine. I could flex the frame back bone up by the steering sten side to side about 2mm and you could see the gap between the tank and the back bone vary as I flexed the frame. It was sketchy. I had a '91 Kawi 125 which had a very rigid frame (perimeter) so I think that's why I noticed it. That bike did some weird things while riding it. The frame would load up and spring back unlike any other bike I'd ever ridden.

I did notice during the '92 season that there were massive changes to JMB and Stanton's bike especially to the swing arm. Adding gussets to the frame is normal for SX back in the day but I counted over 3-4 swing arm changes and these were NOT production swing arms. They were fabricated to look like stock units but like the OP said, the radii on the corners were varied and not production. Great thread! Subscribed!!
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The Shop

CDswinehart
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4/28/2020 2:33pm Edited Date/Time 4/28/2020 8:02pm
FWIW: I was there for the teardown of JMB and Jeff's bikes. For whatever reason (can't recall) Yamaha chose the Vegas round to ask for the inspection. The bikes were stripped to bare frames and swingarm. Both frames were stock yet looked very different with added gussets, which was/is a legal mod.

Jeff's bike was heavily reinforced around the steering head, and JMB's was mostly gusseted around the swingarm pivot/footpeg mount area. The swingarms were stock length and correct, just cleaned up a bit.

As I remember, protest denied.

Their outdoor spec frames later that year may have been different yet again from the SX spec.

Just an observation from that time....

Edit: On further reflection, there may not have been a swingarm issue in this particular incident at all. Just the frames. Hey...it was 28 years ago...
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4/28/2020 7:44pm
Why were swing arms required to be stock?. In the 70s the aftermarket turned out some trick swing arms. Not like the aftermarket couldn’t return to making trick ones.
burn1986
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4/29/2020 2:45pm
Well, it is Honda... They probably threatened the AMA if they ruled against them.
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Ted722
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4/29/2020 8:25pm Edited Date/Time 4/29/2020 8:30pm
Why were swing arms required to be stock?. In the 70s the aftermarket turned out some trick swing arms. Not like the aftermarket couldn’t return to...
Why were swing arms required to be stock?. In the 70s the aftermarket turned out some trick swing arms. Not like the aftermarket couldn’t return to making trick ones.
AMA's Production Rule went into place in 1986 and it included swingarms, but i agree that would be an aftermarket item some would certainly buy. Honda's works swing arms always looked trick, maybe they worked better too.
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kiwifan
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4/29/2020 10:23pm
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess thats the end of this thread. Not sure what is gained by bringing it up for something 18 years ago?
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CPR
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4/29/2020 11:58pm
Hey I think it's an interesting story, especially if someone could put it together with comment from the players involved.
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4/30/2020 12:07am
kiwifan wrote:
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess...
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess thats the end of this thread. Not sure what is gained by bringing it up for something 18 years ago?
Pipe down!
It’s an interesting story, not likely to offend anyone involved and something really quite interesting might come of it.

Keep it coming OP!
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kiwifan
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4/30/2020 2:37am
kiwifan wrote:
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess...
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess thats the end of this thread. Not sure what is gained by bringing it up for something 18 years ago?
Pipe down!
It’s an interesting story, not likely to offend anyone involved and something really quite interesting might come of it.

Keep it coming OP!
hahaha

Seems to me the interesting story ended when it was said there was a teardown and no problem was found and they were legal...what am I missing?
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ACBraap
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4/30/2020 5:28pm Edited Date/Time 4/30/2020 5:33pm
kiwifan wrote:
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess...
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess thats the end of this thread. Not sure what is gained by bringing it up for something 18 years ago?
While 1992 seems like just yesterday, it was actually 28 years ago, not 18.
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chuckdavies
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5/1/2020 2:02am
[img]https://p.vitalmx.com/photos/forums/2020/04/30/424388/s1200_colliseum_92.jpg[/img]

I agree these certainly look more rounded tubes but it could be the angle/lighting/picture? Was the only test they did based on overall look, length and other measurements where this HRC version could have matched the oem?
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kiwifan
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5/1/2020 2:32am
kiwifan wrote:
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess...
Given the OP was about SX, and it was stated there was a teardown to which the Hondas were found to be legal, then I guess thats the end of this thread. Not sure what is gained by bringing it up for something 18 years ago?
ACBraap wrote:
While 1992 seems like just yesterday, it was actually 28 years ago, not 18.
true, my bad, I hit the wrong key Smile
MZ193
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5/1/2020 2:51am
Cool stuff... would like to know how this gone but probably i/we'll never know. Keep the infos coming mofomotojoe.
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