I just put a new piston in on my 87' 250r any comments on break-in ?

 

I just had the top end rebult on a 4 stroke and they said 1/4 throttle for 2 tanks of gas then gradually start opening it up then change the oil after 4 tanks of gas. 2 tanks of gas should be ok before you start opening it up

 

CT raccing has a good page on break in, check out the link..



http://www.ctracing.com/cylinder.htm

 

thanks for the advice, in the manual I had, it said basicly not to go over 1/3 throttle for the first 100 hrs. You know how long it would take me to break it in at that rate. longer than I 've riden in the last year or two.

 

I just rebuilt the top end on my 86 trx250r and I rode it about 3/4 throttle I took it easier than normal WFO but she hasn't had a problem yet.

 

I change my rings every five races. It keeps the engine running crisp. That is a lot of changing when I was racing every weekend. My break in period procedure is simple yet effective. I leave the jetting the same, mix the gas the same. Start the engine, let idle for 5 minutes, shut it down. Let it cool off, I set a fan directly in front of the quad to assist in cool down. Once cool, start engine again. Idle for 5 minutes, blipping the throttle a few times. Cool off with fan again and finally let idle one last time. Cool with fan. Ride as normal.

I havent had any trouble thus far using that technique. CT's page has good tips. After so many ring changes, I just found this worked best for me.

 

When I rebuilt my 86 I did similar to that but ran it for 10 min and shut down, run again and shut down then ride it like you would. one thing I would suggest is if you rebuild the bottom end change the oil after each tank of gass for the first three tanks. helps get all the crap out of the engine from the rebuild.