cleaner Posted January 10, 2014 Report Share Posted January 10, 2014 Anyone know what the ideal overbore size is for my 78 TY250? Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 10, 2014 Report Share Posted January 10, 2014 It depends on which bore you are on now. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted January 10, 2014 Report Share Posted January 10, 2014 and how worn it is on that bore Quote Link to comment Share on other sites More sharing options...
axulsuv Posted January 10, 2014 Report Share Posted January 10, 2014 Can't vote without measuring the barrel ...! Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted January 10, 2014 Report Share Posted January 10, 2014 One that you can get a piston to fit ? 2 Quote Link to comment Share on other sites More sharing options...
cleaner Posted January 14, 2014 Author Report Share Posted January 14, 2014 Still has original piston. I had heard that going 60 over is about it. Just wondered what others have found that works best. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted January 14, 2014 Report Share Posted January 14, 2014 If you want to stay around 250cc, then get the bore measured by the person who will be reboring it. They will tell you from that what size oversize piston to buy. You should always get the smallest oversize that will clean up the bore, so you then have more options for the next rebore. If you want a bigger displacement, you can get pistons up to 2.0mm (0.080") above standard diameter off the shelf made by Wossner, which increases the capacity. TY250 motors can also be made 320cc but this is a lot more expensive because there is a new sleeve and more machining required, and rejetting, and a heavier flywheel 1 Quote Link to comment Share on other sites More sharing options...
cleaner Posted January 20, 2014 Author Report Share Posted January 20, 2014 Thanks Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.