An '82 KTM 495 engine would technically not be Evo class legal in Australia, because it came out of a single shock bike and had a reed valve cylinder (where the '81 495 motor was piston port). You would probably only run into trouble with protests, if you finished with a top three placing at a title meeting. The top three guys would probably end up in the same positions no matter what they were riding anyway. The '82 495 motor in the '81 KTM frame would make for an easier bike to ride though, as the '81 495 was an animal .
Is it true, MaicoJames, that the AHRMA are introducing a 4 stroke class in GP or Ultima ?
Hmmm...
I've read the regs a number of times now and they do not mention 'twin-shock vs single-shock', they talk about linkage suspension.
And, there is no mention of piston-port vs reed-valve.
Going by my understanding of the regs, an '82 495
should be ok for EVO as long as the rear-shock does not use any sort of
linkage.
YZ Yamahas are eligible for EVO even though they're single-shock - they use no linkage, the shock is bolted directly between the swingarm and the frame.
So...
Theoretically, air cooled (yep), drum brake (yep), non-linkage suspension (yep).
Sounds ok to me, but let me know how you go after your first inspection.