How should my bike run during break in period?

I finished my top end job tonight (my first). I ran it for about 10 minutes using very little throttle. It took about 25 kicks to start it. When it started, everything seemed fine. The engine sounded smooth, and quiet. I did notice though that it ran a little "rougher" than before. For example, it killed a couple times when idling.

Is it normal to not run quite as smooth during the break in period?


SHould run the same. Did you just do piston? Shim valves?

I just did a piston, timing chain, and rings. It seems to run good, it just didn't seem to idle real well. Maybe I just need to run it longer.

Someone else just had a similar problem. I believe they had improperly installed the rings, resulting in a rough idle and ended up scoring the cyclinder. Are you confident that you installed the rings properly?

Here's the thread:

SHould run the same.

That is correct. If you changed the piston and put new rings in, you may feel more compression.

Break in period is all of five minutes. You should of ridden the bike under light load instead of letting it just sit there.

If you carb had been sitting with fuel in it, the pilot may be slightly gummed up, pop in a new one, set the fuel screw according to the procedure.

I have always let my bike come up to temp, ride couple easy laps, let it cool down. Warm it back up and ride it like I stole it. Has never failed me yet. Have a 09crf250r with 85hours on it without being rebuilt or touched. Still runs great. Starts within 5 kicks

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