I finished the top end assembly, and she fired right up and sound very good.
EXACTLY how should I properly break it in? ride very easy for how long. Should I not rev the motor 1/4 of max RPM? What SHOULDNT I do, or what CANT I do?

My initial impression when I jumped on it was the torque. Lots more than before... LOTS. I cant wait to be able to crack that throttle more than an 1/8 of an inch!

-Matt

 

There was a break in procedure I ran across on the internet but don't remember where. Ayway, it was for a 2 stroke motor rebuild, but they should be the same. Basically, you let it idle for 15 minutes, then shut down and let cool, then repeat twice I think. Then you ride it, starting out not to exceed 50% throttle then increase by intervals of 10%(I.E 60% throttle, cool down, 70%throttle, cool down) Hope that helped.

 

call whoever you got it from. they should be able to tell you. if not, try Sparks Racing, or Tom Miller.

 

Oregonmxracer's break in way is pretty close. Iwould only let it idle for about 7-8 minutes though. thats what i was told to do by LRD and a few of my quad crazy uncles. If you let itidle for any longer you may have trouble with it overheating. Do it twice. 2 7-8 minute intervals to break in he cam and the piston. then take it for an easy ride. go through all the gears. change oil after first tnk of gas then ride it easy and work your way up over a weekend. dont be to harsh but dont ride it like a grandma. ride it as if you were gonna ride it anyways...

 

Four bangers dont need to be broke in when you only change the piston ........ride it like you stole it !!!!!!!!!!

 

If you installed a new cam I would highly recommend you do not let it idle for break-in. Oil flow to the top end is much lower at idle, four stroke break-in is different than two strokes. Ride it not reving to high or using full throttle for 30 min. then change the oil and filter. This will get any metal contaminants out from the break-in, then ride it for an hour or so varying the rpm but not loading the motor too hard for any extended period, after this you should be good to go. Recheck the valve clearance after a few hours ride time.