Do they need much running in compared to just a new piston as i will be starting a running in period on my rebuilt engine this weekend the bike has a nikosil cylinder and single ring piston and i have been told to do 3 heat cycles and and a few gentle rides to ease the piston in but what about main bearings and new crank would these need more time to settle thanks.
no mate, just treat it same, a couple of gentle heat up cycles and cool... go easy on it for a few miles, then check and re torque head & cyl nuts then ur good to go
yeah thats same as every manufacturer...500-1000 miles
when we used to race mx, we would wreck the engine in the morning on an unlucky day, strip it build it at dinner track side, back in frame, warm up & cool and another good warm up then it would be flat out round track for weeks on end so , good oil and a good warm up, and ur good to go
When you're racing in order to have THE best chance you want to rebuild the engine before every race. To get every bit of compression possible before everything loosens up
I personally run it in for 500miles. Probably will be fine after 3 heat and cool cycles as people say but i prefer to do as reccomended by the masses and be safe.