First of all, forgive me for not knowing everything, but please let us know -- what's a TRE?
Okay, on to Production class modifications. If you've got your (SCTA '07) rulebook, read page 104-5 to see what things may be modified. Also read the two opening paragraphs, which state what must remain unchanged -- then see the last line -- "any performance modifications must be out of view." Note: "The exhaust system, looking at the end (down its centerline) shall be unmodified, i.e. the exit diameter of the canister (muffler) cannot be enlarged." So -- if you think you can improve your bike by gutting the muffler, go ahead, but put it back together after taking out the inside stuff so that there's no way we can see the difference -- even to any restrictors that might be in the outlet. There's other stuff -- but the production class is for bikes that aren't too far from what Joe Six-Pack can buy at the dealership.
Now skip ahead to pages 115-116. "Production engines must be the same model as the model of the frame being used and must have stock external appearance." Inspectors, like many folks, don't have X-ray eyes to see if the bore has been changed form production, nor can we tell if the crank is a non-production length. There's your permission to change displacement. But read on: "OEM displacement determines the displacement class for competition. Displacement may not be increased beyond that class limit." So -- if your scooter was a 1098 Ducati when you bought it from the dealer -- you aren't allowed to bore & stroke it to beyond 1350 cc. And so on. . .
But read on some more: "Carburetors or throttle bodies must be OEM for that model production engine." How you gonna feed all those new-found cc's with stock carb/fuel injection?
And so on. There's room for some experimentation and variation in production class -- but not too much, or you'll be in modified.
Bonneville, El Mirage, even Maxton -- although I don't have an ECTA right at hand to quote. Anyway, they're ll about the same.
