Pre 78 Rule changes

[JohnnyO]

There really isn't much wrong with our rules as they are, it's a pretty successful formula. The classes were huge at the Nats with a lot of variety of bikes, there was little or no protesting and as far as i know only 1 bike was penalized in the results.
You're always going to get bikes that don't comply no matter what the rules are.

[John Orchard]

What do I need to do to make my RM125B comply?

I'm thinking of filing 3mm off the bottom of the damping rod should fix the forks.  With fitting 5mm longer shocks, stock travel at the rear is 8.8" so I can slip a 5mm alloy spacer under the bump rubber?

[JohnnyO]

What do I need to do to make my RM125B comply?

I'm thinking of filing 3mm off the bottom of the damping rod should fix the forks.  With fitting 5mm longer shocks, stock travel at the rear is 8.8" so I can slip a 5mm alloy spacer under the bump rubber?

Filing 3mm off the damper rods will only give you 3mm less travel, that's not going to make any difference. You're better off using different top out springs, replace the long soft one with a car valve spring that is shorter but harder and doesn't compress as much.
You need to measure the shock shaft travel to work out the rear travel, fitting longer shocks only gives more travel if they have longer shafts than the std shocks, every brand will be different. Some shorter aftermarket shocks will have more shaft travel than std.

[John Orchard]

I only need 3mm less travel on the front don't I?  Standard fork travel is 9.1" = 231.14mm.  9" = 228.60mm,   231.14 - 228.60 = 2.54mm.

I'll check the stroke of the shocks when they come.

It doesn't worry me shortening the travel by such a small amount.

[Nathan S]

I only need 3mm less travel on the front don't I?  Standard fork travel is 9.1" = 231.14mm.  9" = 228.60mm,   231.14 - 228.60 = 2.54mm.

I'll check the stroke of the shocks when they come.

It doesn't worry me shortening the travel by such a small amount.

Yep.

[Davey Crocket]

Having 9.1 inches of travel will not get you into trouble....dont listen to the drama queens on here John. Most bikes manufacturers travel spec's are tarted up, I have 125B forks in my A and for the life of me (and I'm a fat bastard) I cant get any where near 9.1 inches of travel.....using the zip tie method around the fork stauchion trick..more like 8.5 inches....and I run 20psi of air in them!

[worms]

I think the pre78 rules have served us well, remember we are just custodians of the sport, pre 78 bikes are a unquie class of bike and i think the last thing we need is another rule change.

worms

[FourstrokeForever]

I don't think the rules need to be changed to allow ANY bike to have more suspension than what it came with standard and the 9 inch seems to work very well for the class. However, the certain bikes that were manufactured before 31/12/77 that did have more WHEEL travel (remember, it is wheel travel and NOT shock length that must comply with GCR's) should be allowed to run as they were in the day without the owner having to rework the suspension. I agree with Slackwell. It's not about trying to add more suspension to the entire class but rather allowing bikes that had the extra travel off of the showroom floor to compete as they were. For example, there could be "exceptions" to the Pre78  9" suspension rule where a bike was manufactured with more travel. The onus of proof of specification would be with the owner/rider of said bike
As has been said, some early LTR bikes handled like a wheelbarrow full of walruses. The forks flexed all over the place and the swingarms weren't much better. In a lot of cases, more is less in that the bike with the extra travel and sky high seat wasn't that good anyway. At the end of the day, a good rider will always be able to ride at the front, no matter what bike us "average" riders have under us.
I stand by my opinion (and that is all it is) that perhaps our GCR's should follow what the yanks and poms have in their rules. It is afterall all about getting bums on seats and great machinery on the track.
Racers and Manufactures have been modifying motorcycles since the beginning of racing and I feel that if someone wants to build a special AND it complies with the rules, then the bike should be able to compete. Take a look at some of the bikes the Brits and Swedes build just so they can have a ride. 1982/3 model bikes built "backwards" with twin shocks, skinnier forks and drum brakes etc. so they can compete in the Evo class. I for one love seeing these "specials" and there is no denying that they get huge numbers of bikes and riders even at club level events......

[motomaniac]

I only need 3mm less travel on the front don't I?  Standard fork travel is 9.1" = 231.14mm.  9" = 228.60mm,   231.14 - 228.60 = 2.54mm.

I'll check the stroke of the shocks when they come.

It doesn't worry me shortening the travel by such a small amount.

I would check where the compression holes in your dampener rods are in relation to the top of the bottom out cones before you start hacking away with a file John( actually I wouldnt hack it at all) If the holes are right above the cone taking away 3 mm will move them partially below ,effectively reducing the comp hole and adding alot of comp dampening.

[John Orchard]

Cool, thanks, I'll pull them apart and see what I can do, might file the cones down 3mm also if they cover the comp damping holes?

[09.0]

I stand by my opinion (and that is all it is) that perhaps our GCR's should follow what the yanks and poms have in their rules. It is afterall all about getting bums on seats and great machinery on the track.

They have been copied from the U.S.
The Americans can all run within the rules and so do the majority here.
If the time was spent in the shed instead of on here and writing to the powers that be, job would be done. Can't help but think its another case of one person wanting to change the rules to suit himself.
I also must say I do understand the fact that it's how it came from the factory but I think the people that wrote the rules have got it right.

[vandy010]

I also must say I do understand the fact that it's how it came from the factory but I think the people that wrote the rules have got it right.

i agree.
we're on a good thing at present.
yes we're riding old bikes but we're also in the present year and our sport is healthy as can be and for good reason.
my 2 bobs worth is to keep things the way they are.
Vandy

[TM BILL]

For what its worth i too think leave as is  the system does work and its all about preserving an era and maintaining a balance  .

It does seem a little strange reverse engineering to fit into a class but a line has to be drawn and i believe where the line is now is a good compromise .

Lots of good advise and common sense coming out in this thread .

I was very vocal prior to the nats on this subject  but with the huge succsess the nats were i think that speaks volumes .


Whenever a rule is added or revised the vollenteer officials have to see that it is adhered to , as it is the scrutineers seem to have a handle on it and competitors are understanding of the rule .

I would like to see a schematic diagram of the system of measurement in the MOMs so anyone can check there own suspension travel the same way as the scrutineers .

Its great to see the earlier classes so well supported at a national event  long may it continue 

[firko]

I also must say I do understand the fact that it's how it came from the factory but I think the people that wrote the rules have got it right.

Brad, for the most part AHRMA is a pretty good organisation but in a number of cases they get it very wrong. Back in 1987 when pre 75 was the only game in town we were looking for a standard to base our rules on so we took the overall philosophy and basic guidelines from the CVRG (California Vintage Race Group) the predecessor to to AHRMA as they'd been running successfully under Dick Manns leadership for a few years. The basic pre '75 rules were adopted almost verbatim from the CVRG rulebook and we added our own pre '70 class and the British pre 65 regs into the mix. Right from the beginning we ran the 7" and 4" suspension limits, with Maico, CCM and some KTM's having to fit restrictors to bring them back into line with the majority of eligible machines. A couple of years later I asked Dick why the CVRG had gone with pre 75 and the 7"x4" limits when there were clearly bikes that fitted the year cutoff but failed the suspension test. I asked him why they didn't make the cut-off pre '74 (as the Poms later did) as that would cut all of the suspension checking out of the scrutineering. His answer was that they'd (wrongly) thought that all bikes of the era were within the 7" and 4" limits, they'd been told "on good authority" that the LTR Maicos were '75 models and weren't eligible. He went on to say that if he could have done it all over again he'd have gone with pre 74.

The CVRG got it wrong with their pre '75 regs so there's a distinct possibility that a similar thing has happened when the AHRMA rule committee sat down to work out the pre '78 regs. Maybe they didn't research the eligibility of all bikes as well as they should have and came to the conclusion the 9" was the market upper limit when in fact, a number of bikes were clearly shown to have over 9" of travel. For any democratic committee to make a correct decision all of the variables must be considered in making that decision. To me it seems so much more sensible to include as many bikes as you can into a class, not exclude others because someone got their research wrong.

[Tahitian_Red]

AHRMA's "Historic" (pre-78) class is a special one.  So much so that we outlawed Novation swingarms to keep bikes looking era correct.  The 9 inch limit is there to protect another special era, 1975, when it all took off.  Just as the '74.5 and carry-over '75 bikes have to use restrictors to keep from outclassing the 74 models, so do the '77 bikes that have more than 9 inches of travel.

I prefer era racing, but the AHRMA rules have stood the time.  In my ideal world any bike built before 1978 could run it's stock suspension travel and the 1975 bikes would have their own class, but maybe that's why I'm no longer on AHRMA's Post-Vintage rules committee.