what is the best way to break in a 4 stroke after a rebuild , be easy for a bit , or ride like normal ,but use throtle in short bursts ?

 

If you piddle around riding it easy and don't create high compression first thing, the cylinder wall will wear into the rings, rather than the rings wearing into the cylinder wall! If you don't do it right, you engine will always be down on compression....

http://www.mototuneusa.com/break_in_secrets.htm


What I do to achieve this is hillclimbs! Running petroleum oil (Maxima Premium), I climb a nasty hill at full throtle, then more importantly, I turn around at the top and come down it in low gear under heavy engine braking. This creates max compresson, which flattens the rings, so they will seat properly. First day, I do this 3 times, then I park it and let it cool down overnight. Then next day I do it again, and I repeat this every day for 1 week.

Then I do easy to moderate trail riding for 10 hours, to wear in the bearings. After that, I ride normally, and at 15-20 hours I change to an ester synthetic oil, like Redline, or Maxima Extra or Ultra.