I just put a new top end on my 400ex,
what is the best way to break it in.
thanks

 

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

This is controversial, but on all my recent machines I have gone with Motoman's method. Use a petroleum oil (Honda GN4) during break-in, then you can switch to a synthetic if you like.

I am religious about "heat cycling" my new engines. That is, I warm it up completely and then go climb one of the monster hills behind my house a couple of times. I go up at near full throtle, then come down in a low gear for lots of compression braking. Then I cool it off completely, and do it again the next day. After about 5 times, I then ride it normally for about 10 hours, and switch to Maxima Extra, ester synthetic oil.

 

Make sure you let it warm up completely, then run it like you stole it.[img]i/expressions/face-icon-small-smile.gif[/img]

 

THANKS FOR ALL THE HELP

 

Everyone has a different method. When a customer ask me how to break in his new top end i tell him just ride it like he is going to ride it no different. but when i give the bike back to him it has been started and rode for about 5 min. It does not take long for the rings to seat.

 

i do pretty much what reconranger does but I will let it idle for a few minutes for the first couple of cycles and then ride it for a few more cycles. Always letting it cool down completely before the next cycle. On my 2 strokes after about 5-7 hrs run time I will tear down the top end and sand/polish the high spots on the piston and put it back together. I also put my 2 stroke engines together virtually dry.