Wheresthericego's 1983 ATC250R "air fooler" February 06, 2013, 09:05:43 pm I know this isn't a "quad" but it is becoming quite the project so I figured it deserved its own little slice of TQC heaven. It all started with an engine missing 5th gear. The engine came out of the frame approximately a year ago but I didn't get my hands on it until about two weeks ago. The determination was made to split the cases and swap out the tranmission. When I removed the top end, I found this gem: Not too bad on that side, some light scratches possibly some evidence of a cold siezure. It looks bad but really, that's just a lot of staining. The exhaust side, however: That's not just staining.... That's actually coke (ash) built up in rather large gouges in the piston thrust face. I measured the top end and it's about .002" tapered down through the middle, enough to be slapping around in there. Of COURSE, this top end is on its last life, .080" (72mm) oversize.... I am, however, leaning towards fitting a TRX310 .010" piston (72.25mm) in it and the spacer plate necessary to run it. It means removing material from the top of the block to the tune of 3/16" but I believe it can be made to run (and run well) and this leaves LOTS of options for piston overbores (the 310 kit runs from 72mm to 73.5mm). I want to talk to cometic about a spacer plate and LA sleeve again about the piston before pulling the trigger on a fancy new piston not being 100% it's going to fit :- More pics as the work gets done!