top end break-in

[edz250r]

I know this has been asked in the past, but the search pulled up about 50 pages and I couldnt find anything in the subject lines.

Whats a good method of breaking in your new top end/piston?

[spdygonzalez450]

what i did with mine was ran it with the amount of oil i planned on running. i just fired it up let it idle for a little blipping the gas a little at a time but not too much, did that one for a little then got on it and rode changing the rpms and not letting sit at one rpm too long and not going over half throttle for the first time. once it is up to running temp stop and let it cool completly, than do it again one more time getting on it a little more than before. than cool it and then one last time on it pretty good and then after that ride it like you stole it. that is what i did for the most part on my bike and it worked good for me.

[Golden Joker]

I heard riding really hard is good.

[YFZRob]

The most important factors are heat cylces and load changes. You want heating and cooling of the top end throughout the entire operating temperature range, and you want to do this at LEAST 3 times. When you are running it through these heat cycles, vary your RPM and the load on the engine. What I do is heat cycle it in the garage 3 times for about 5 minutes each. I'll fire it up and let it idle with choke on for about 30 seconds, then let it come down to normal idle RPM with the choke off. Now vary the idle RPM lightly for the remainder of the 5 minutes. Just don't let it run at a set RPM while doing this. Then on the 4th firing, I take it out and cruse around varying loads up to 1/2 throttle and varying RPM all the time. Ride it around a good 10 minutes or more. Let it cool all the way again. 5th time firing it, run up to 3/4 throttle with the same conditions as 4th time. 6th time HAVE FUN! BUT make sure you do WOT plug chops to ensure the jetting is correct.

[JTRtrx250r]

Originally posted by YFZRob
The most important factors are heat cylces and load changes. You want heating and cooling of the top end throughout the entire operating temperature range, and you want to do this at LEAST 3 times. When you are running it through these heat cycles, vary your RPM and the load on the engine. What I do is heat cycle it in the garage 3 times for about 5 minutes each. I'll fire it up and let it idle with choke on for about 30 seconds, then let it come down to normal idle RPM with the choke off. Now vary the idle RPM lightly for the remainder of the 5 minutes. Just don't let it run at a set RPM while doing this. Then on the 4th firing, I take it out and cruse around varying loads up to 1/2 throttle and varying RPM all the time. Ride it around a good 10 minutes or more. Let it cool all the way again. 5th time firing it, run up to 3/4 throttle with the same conditions as 4th time. 6th time HAVE FUN! BUT make sure you do WOT plug chops to ensure the jetting is correct. ;)

[edz250r]

Thanks guys!

[mdl76]

I break my motors in by properly warming them up and then riding fairly hard and do a lot of engine breaking(using the engine to slow you down). If you baby the engine during breaking, the rings will not be fully pressed against the cyclinder and then you will not have a nice tight ring to cyclinder. This has be researched and proven.

[BLEEDRED]

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

This is the best advice I can give you. This is how I broke my 440 in last year and when I tore it apart this winter the rings were seated very well, you could see the color difference on the piston...everything below the top ring looked brand new.

[edz250r]

Does that method apply to 4 strokes only??

[BLEEDRED]

I don't know...didn't realize that you were talking about a 250R...better not use my advice. Sorry.

[edz250r]

Hey...this is the 250R forum afterall!! Just busting ya! LOL