Amateur at rebuilding, bent a ring.

I bent a ring (have new ones now) trying to get the piston in the cylinder, looking for some tips, or if I should be using a ring compressor. It's an 06 crf250r. Also, is it really okay to not put any oil on the cylinder?

Replace the ring. These are high performance engines with exact tolerances.


Get the ring compressor - it helps (a lot).


I always put a lite coating of oil in the cylinder on rebuilds. That and a ton of oil on the valve train portion. Then to ensure oil is getting to all the major parts, I will kick it over (fast and vigorously) with no spark-plug for about 20-30 kicks. Check the valve train to see that oil is being pumped though the system. Replace the valve cover, gas tank etc. Start it up and let it idle for about 5-10 min. I usually put a fan in front of the bike to help cooling once up to temp. During this time I am looking at everything on the engine, for leaks odd noises, smoke anything. 

put the clip in on the right hand side of piston first. Add rings to piston.. (CAREFULLY). Put the piston in the cylinder before connecting the piston to the connecting rod. Make sure the piston is facing the right way and then install piston pin and remaining clip and finish sliding piston into the cylinder. 

Letting a new, or rebuilt, top-end idle for 5-10min is about the worst thing you could do to one of these motors. They need high cylinder pressure asap to seat the rings properly, so you at least need to ride it around.

Eddie, my plan was to let it idle/warm up for about 5 minutes, and then ride it hard for 30 min and do an oil change. What would you do differently?

Thank you Brobbo and Tvalliere.

5min of idling is a bit too long for me is all...

Will I agree a hard break-in is required, I have to disagree, letting the engine idle for 5-10 is the worst. (ok 10 min is a long time). Statistically speaking the time it takes to warm up and quick inspect for oil leaks or sound anomalies is an absolute critical  measure in averting a catastrophic failure. 

Even at idle speed for that duration does very little to seat rigs improperly or at all. Its the half measure after the fact, that does little good. As in putter around for the next 30 min or so. 

For me:

Start engine,

high idle to ensure oil pressure

Inspect vigorously while warming up - by the time I'm satisfied all is good, its coming up to about <5min

Hop on - first 50yrds slow to feel hear for any signs of trouble

After that WOT through the gears a few times .


in the end I suspect our time lines and methods or mostly similar. For me, I would contend the worst option is the mid rpm to seat in the rings. 

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