will a trx250r engine fit in an 85 atc250r?

[dizasterzrfun69]

Well my engine needs the case welded around the shifter (or just replaced) so im looking on ebay for another engine/case. I know that the 87 and on trx engines were long rod engines but will they fit in my 85 atc250r? Will an 86 trx engine fit?? what engines will and wont work? I just finally got this liquid cooled R so im starting out not knowing much about them.

Kevin

[InPiEcEs]

Any 250R engine 1985-1989 will bolt into an 85-86 ATC. They are all physically the same. The only issues you will have interchanging stuff is jugs/cranks. The way to get around that is.........if you have a short-rod crank, use a short-rod piston.
If you have a long-rod crank, use a long-rod piston.
If you use a long-rod crank, and a short-rod piston, you will need a spacer plate. They moved the piston pin to accomodate the longer rod.
If you use a short-rod piston on a long-rod crank, the piston will be a few mm to high, because the pin is lower.
Jugs are all interchangeable, with 88-89? having bridged intakes, which helps against piston skirt cracking a little better.

[Psychotrike9]

yeah the 88-89 jugs are the same also.