mono to t/s conversion for evo

[lms6201]

is there any restrictions or issues converting a link mono to twin shock for use in evo, i know a popular conversion for twin shock trials in the uk is the ty250 (they didn,t get the 350), any remarks or rules pls ?

[Noel]

Hi,
Below is an extract from the MA GCR's
"At club level I doubt there would be a problem but if you turned up to a
National event you may have to prove that you are eligible


18.7.11 Evolution Class- General
18.7.11.1 Evolution class shall be run as a national
championship and can be independent of
other classic Motocross classes.
18.7.12 Evolution Class- Eligibility
18.7.12.1 Bikes will be OEM.
18.7.12.2 Modifications converting later equipment
to comply will not be allowed
18.7.12.3 All components will be of the period the
machine was manufactured.
a) No linkage suspension,
b) No Disc brakes,
c) Air cooled motors.
18.7.13 Evolution Class- Classes
a) Solo 125cc,
b) Solo 250cc,
c) Solo 263cc and over.
18.7.13.1 No age-group classes will be run.

[lms6201]

tks noel , the oem bit will kill that idea it seems even though the bike is ,81

[gorby]

(18.7.12.1 bikes will be OEM)

can anyone clarify this rule for me?

does this mean hybrids are not allowed ?

[evo550]

Hybrids are allowed (and should be encouraged) as long as they are of components from that particular era.
i.e. If you have a 1978 IT 425 you can fit yz465 suspension components It's all evo.
 But you can't fit a '84 cr500 motor to a 79 cr250 frame and call it evo....the motor is from a different era.

[Nathan S]

Too easy.... Take a 2007 KTM250 with the water jackets machined off and fins welded on, drum brake conversion (!) = the 2007 NathanMobile250MX. It'd have 90% of the performance of a 2007 KTM, and would be significant faster than the 'real' Evo bikes....
Yeah, it'd be dirty and cheatin' and wrong, but it would also be perfectly legally defensible too.

[lms6201]

the project would be for a 1981 kx ,which is already there except for the see saw linkage 

[TM BILL]

NO NO NO  Dont go cutting up bikes sell the 81 & buy a twin shocker .
What size is the 81 ?

[GMC]

In what way would it be legally defensible?

18.7.12.2 Modifications converting later equipment
to comply will not be allowed
18.7.12.3 All components will be of the period the
machine was manufactured.

I'm with TM, allthough I admire a good hybrid, I would hate to see early single shocks butchered simply to become Evo bikes.

[Nathan S]

No age limit for Evo. So it's a 2007 model NathanMobile 250MX, with no later (than 2007) equipment fitted.

The rules make the assumption that you're starting with an old bike. There's no written basis behind that assumption, so a new bike that meets the criteria is legally defensible.

No, I'm not planning on doing this!

[lms6201]

no butchering , simply i was going to fabricate a mount in place of the see saw and from that mount two  short shocks to the link mount on the s/arm ,  but would be useless if unable to use for evo , it,s just that my local club runs evo and nothing else , guess i could ride vet

[211kawasaki]

Its never going to be legal as the OEM rule applies. In other words if the bike left the factory as a mono then no matter what you do to it (the shock mod) its never going to comply. OEM means original equipment manufacture.
Sure get a trick set of shocks of a fancy swingarm (for your existing twinshock evo ride)- so long as you could by one within the period of the class of bike you race or the part is an acceptable replica such is the case with many after market frames. This pretty much applies over all the VMX classes.

Don't cut up a Kawasaki like an 81, these things are real cross over bikes between air cooling and linkage, really nice and rare things.

Tanner

[lms6201]

221, i have already aknowledged noel,s posting of the rule and i have given an idea of my non chop mod , but response is intereting , now does any one have a coil and a cdi for a 420 ?

[Lozza]

No need to go hacking up a 07 Nathan, we just bring the 77 up to 07 spec