CR 250 Question

[Nathan S]

Can't put pre 78 style shocks on a pre 75. But you can buy new period style ones.

Says who? Pre-75 (and older) have the most restrictive rules, and even they say nothing about age/model/length - just 4" of travel and no remote cannisters.
Fitting an '85 CR shock into an '84 model bike might be a dumb idea, but it doesn't stop the bike being pre-85 legal.

If the 85 model part is the same (or is a component that is allowed to be replaced), then it doesn't matter that its an 85 model part.

[090]

I think you know what I'm trying to say. You can't put rm125b shocks on a 74 cr125.

Fitting an '85 CR shock into an '84 model bike might be a dumb idea, but it doesn't stop the bike being pre-85 legal. My point is that it shouldn't be legal or encouraged. By making that type of statement does put ideas in peoples heads.

If the 85 model part is the same (or is a component that is allowed to be replaced), then it doesn't matter that its an 85 model part.Which it isn't in your example. The similarity is it is a shock with a reservoir

The only point I want to make, as clearly as I can, is that it should be discouraged to bastardise bikes with incorrect components especially when there are correct parts available. Mainly to preserve the bikes as they should be.

[Nathan S]

My point is that it shouldn't be legal or encouraged.

Why is using an 85 model shock worse than using a 2011 aftermarket shock? I genuinely don't understand the train of logic there.

If the 85 model part ... (... is a component that is allowed to be replaced), then it doesn't matter that its an 85 model part.

The only point I want to make, as clearly as I can, is that it should be discouraged to bastardise bikes with incorrect components especially when there are correct parts available. Mainly to preserve the bikes as they should be.

This I agree with.

[motomaniac]

My point is that it shouldn't be legal or encouraged.

Why is using an 85 model shock worse than using a 2011 aftermarket shock? I genuinely don't understand the train of logic there.

The usual total waste of time.The 85 shock (as Brad said) is longer ,also has a 46mm piston with more or less mosern style valving the 84 doesnt and has limited possibilities and is als on 40mm piston .The linkage and swingarm are different and so is the linkage bracket at the frame.The plastics are also different, to change the sidecovers you need to do also the airbox,the tank means the radiators shrouds and the radiators need to change as well and then the pipe wont clear the tank as it sits lower like the radiators. The seat is mounted further up on the subframe so you need to change that also.Honda changed to a flat slide carb in 85 so obviously thats not available in 84 - unless you use one of a different brand of bike - maybe a mikuni but the bell housing is different so you need to mod or adapt to fit the airboot.The front end includung the forks,wheel,mudgaurd and triples are completely interchangable, the rear gaurd isnt.
The 85 motor is a slug the 84 is a rocketship , for forksake just get a bike to fit the class as it comes.

[motomaniac]

[/quote]
The 85 shock is so different it will not go in without huge surgery . You would have to modify so much , its not a 84 anymore . Thats what 090 is trying to say , and he is absolutely correct.
[/quote]

Yes he is Walter.

[090]

Why is using an 85 model shock worse than using a 2011 aftermarket shock? I genuinely don't understand the train of logic there.

The logic as I see it is that the rules say you can use a 2011 after market shock that is designed for that bike, where as fitting later model components to an earlier class err to the side of illegal or if not just need to be discouraged.
My initial post was more to point out , why give people that want do want to bend the rules some sort of justification by saying in your e.g put an 85 shock in an 84. The fact it doesn't fit even though is fact, is not the point I want to make.

[Nathan S]

The logic as I see it is that the rules say you can use a 2011 after market shock that is designed for that bike, where as fitting later model components to an earlier class err to the side of illegal or if not just need to be discouraged.

Even when I disagree with you Brad, I can usually understand where you're coming from.
This is not one of those times.

What if it turns out that a 1995 YZ250 shock fits straight into an 84 CR250? Why is it "illegal" or to be discouraged when a brand new aftermarket shock is OK?

[firko]

Without knowing the mechanics of this particular situation or offering a yay or nay opinion....this is yet another example of the urgent need to start upgrading and clarifying the MoMs eligibility criteria. The more new divisions that enter the sport, the more inadequate the now 20 year old eligibility requirements appear. The revamp needs to be started as soon as possible.

Shane, Dave T, Ross and other MA officials,  this is a serious situation that needs to be attended to ASAP. This is serious, long term committee work that must be done right, and to do that a 'Brains Trust' needs to be assembled to oversee and consider input from individual marque specialists. It's impossible for one person or even a committee to possess the knowledge needed to do this properly but I honestly believe that there are people within the vintage community who are experts in their own particular area of interest that can really contribute.

As it stands right now the rules for every division ranging from pre 60 right through to Evo and pre '85 feature double meanings, vague language and blatant mistakes. In some areas such as suspension, and carburetion for instance, the details need to be mapped out in 'what's in' and what's out' detail to make eligibility rulings a black and white situation...removing all of the grey areas.


 

[Slakewell]

Seems common sense has left this thread.
Shocks are a consumable not a core component.

[firko]

Shocks are a consumable not a core component.

You betcha Mick...but what's to stop a handy boilermaker like yourself from repacing the whole shock and linkage setup from a 2011 bike to an '84 CR500? The way the rulebook reads at present there's nothing to stop you doing that. Now I don't think that many of us would agree with that extreme hypothetical becoming a reality so it's pretty bloody obvious to me that what you can and what you can't do needs to be mapped out in detail in MoMs, starting sooner than later. 

[paul]

no questions from me today

[090]

The logic as I see it is that the rules say you can use a 2011 after market shock that is designed for that bike, where as fitting later model components to an earlier class err to the side of illegal or if not just need to be discouraged.

Even when I disagree with you Brad, I can usually understand where you're coming from.
This is not one of those times.

What if it turns out that a 1995 YZ250 shock fits straight into an 84 CR250? Why is it "illegal" or to be discouraged when a brand new aftermarket shock is OK?

To answer that question, it is in line with the rules for all other eras. Period shocks or replacement new ones to suit that era.Same should apply in the later classes. The only difference is that they are all similar by pre 85 hence your reasoning.
Playing devils advocate will, I feel,  give some people the ammunition to justify doing some shit things to their bike. Such as putting 2011 forks on an 85 model bike (random e.g.)

[Lozza]

It's not hard just look at the road racing rules. That defines major and minor components, major components have to be period, minor are open. Then the whole eligablity criteria would be a easy yes/no with fatboyracing(??) proposed database and a log book.
The data base with a few pics would be 10 pages pics maxiumum would show follow on major components, so any scrutineer could look at the pic eg triple clamps, and decide quickly.With a log book you are outlining the modifiactions to the bike.Under rear suspension eg 84 CR 250 frame fitted with unknown mid 90's shock. Frame mounting points unaltered. Linkage from 2010 RMZ 250.
 

[Captain Bilko]

I've never thought a lot about it but log-books would probably be a good idea (as long the RTA/Cops can't fine you 600 bucks for not signing your page off.... )

[Nathan S]

Period shocks or replacement new ones to suit that era.

You've made that up - its not in the rules, or even implied in the pre-85 rules.


FWIW, I offered some private advice on the 84 vs 85 CR250 thing, and tried to hose down the notion that the '85 model was a carry-over bike. I'm guessing the bike's owner didn't like the answer and has asked for official confirmation through the Commission.