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new top end break in

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i want to do a new top end (i bought the bike a month or two ago, and have rode it 3 times since i bought, changed the oil before the last ride) and i was wondering what steps people take to break in a new 2 stroke top end on an 01 rm250?

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Everyone does something different so this may get a little hairy. I do about 5-6 heat cycles. Letting the bike come to full operating temp then shut her down and let her cool down completely (just running not riding). Then I ride the bike up to 30 min not going past 1/2 throttle. Once again letting her cool completely down. Next I do another 30 min at no more than 3/4 throttle. Cool down again and then she's ready to Rip.

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The heat cycles are important, but I don't think you need 5-6 for just a top end. Warm it up really well (the radiators should be hot to the touch). Let it cool down for about an hour. Start it up, warm it up and then ride for about 10-15 mins being very careful not to lug or rev the engine and no more than 1/2 throttle. Let it cool down for another hour. When cool retorque the head and go ride.

Basically what spike said, but with only 2 heat cycles. Use more heat cycles when the entire engine is brand new.

Good Luck!

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Proper installation of new parts and care to keep things clean is most important.

I've never done more than one heat cycle, ever. I'm not knocking those who do them; rather, I feel a bit of pity for all that time wasted because of how this kind of information gets handed down over time. Somewhere along the line a misconception has been carried along about how "cycling" the engine does something that can't be achieved in one, maybe two settings.

Here's what Eric Gorr states about "break in". Notice the lack of heat cycles . . .

When you initially start the engine after a rebuild, manipulate the choke to keep the engine rpm relatively low. Once the engine is warm enough to take it off choke, drive the vehicle around on flat hard ground. Keep it under 2/3 throttle for the first 30 minutes. Two common myths for proper engine break-in are; 1) Set the engine at a fast idle, stationary on a stand. 2) Add extra pre-mix oil to the fuel. When the engine is on a stand it doesn’t have any air passing through the radiator and it is in danger of running too hot. When you add extra oil to the fuel you are effectively leaning the carb jetting. This can make the engine run hotter and seize.

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Start the bike and then pin the throttle. She will definitely be "Broken" in. Despite all the different ways the most important thing is to take it easy on a fresh engine. Whether it be with heat cycles or riding with less than 2/3 throttle the rings need time to seat.

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Despite all the different ways the most important thing is to take it easy on a fresh engine. Whether it be with heat cycles or riding with less than 2/3 throttle the rings need time to seat.

Most important part!

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just ride her lightly and let her cool often, thats the main parts. now to what extent you want to do that to is more of a personal thing. if you are like me you just want to let the friggin thing rip but you have to contain yourself to about 1/2 throttle it was hard for me

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