A forum for owners of Yamaha TTR250 trail and enduro bikes!

SussexTony · Senior Member

New pistons

SussexTony · Senior Member

If I remember rightly, it never took long in a two stroke motocross bike? Does it take longer for four strokes ?

TTRfan · Super Guru

You are not the first to ask Tony! See https://ttr250.activeboard.com/t60341684/running-in-new-piston-and-rings/

I usually restrict throttle opening to about half for the first 40-50 miles, then three quarters for another 50 miles and then full throttle for only short periods. No sustained full throttle until I have put on a few hundred miles - but I rarely need to do that anyways.

It's not so much about speed or revs as trying not to "lug" the engine in too high a gear. If in doubt change down a gear or two wink

There is a body of opinion that race 2-strokes need no running in - but our motors need to last more than a few quarter hour races before rebuilding biggrin

SussexTony · Senior Member

Thanks for that , much appreciated!