Breaking in New Topend

[rooster300ex]

Is there certain things u need to do to a fresh topend. u know like setting the rings etc.

[DamageInc]

I've always done it like the motoman:
http://www.mototuneusa.com/break_in_secrets.htm

The theory behind it is that the rings won't seat properly without high cylinder pressure. If you ride it real easy during break-in, the cylinder gets glazed and the rings never seat properly. You don't want to hold it wide open for log stretches, because the extra heat generated during ring break-in, combined with the long full throttle run, could possibly scuff a piston (or cause glazing). The key is to use a lot of short full throttle bursts.

Like Motoman says, this is a controversial subject, and you will hear different answers from different people.

Do a google search on something like "engine break-in cylinder pressure", you will find a lot of info on this subject.

Oh, and make sure you change your oil after a tank or two of gas, to get the break-in metal out of there.

[cals400ex]

i run mine pretty good too. however, you need to warm it up first.