running in

[nolzey]

any tips on running in? new top end on my yz400f. dont want to glaze the bore. how long till i can open up full? i was told to pick the biggest hill and ride up about half revs, load the motor a little is that right?

[flintlock28]

Before you do anything, read the information below. I have not used this procedure before, but next time I do my top-end, I'm going to follow Motoman's suggestion. A number of people on TT agree with his info.

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

[grayracer513]

Both of these, and the break-in procedure in the manual are essentially correct. The important thing is to be neither too easy nor too hard on the engine for the first hour. Then change the oil and ride it.

[Kent Rathgeber]

Both of these, and the break-in procedure in the manual are essentially correct. The important thing is to be neither too easy nor too hard on the engine for the first hour. Then change the oil and ride it.

Don't forget to replace the OIL filter as well. Once you've done that, clean your air filter and ride the snot outa it!!?