Engine rebuild, now hard starting

Just had my '01 top end rebuilt (piston pin circlip came out/ broke, lunched everything including valves). Replaced cylinder, 3 valves, piston (switched to Wiseco hi- comp, using Ultimate 4 fuel), etc. Weird thing is, now bike is very hard starting. Have to use the hot start even when cold and jump start it when hot. Always started fine before! Any ideas?

maybe the high compression piston is causing the trouble?!

Since you said that you rebuilt the top end and replaced the head and three valves, run a compression and a leak down test. Its possible that your valves are not seated properly. A similar problem happened to a freind of mine and it turned out to be a valve. But he wasn't running a high compression piston.

How does the motor feel when you kick through? Does it feel tight or soft?

Did you take a plug reading?

Tight valves cause hard starting. If your valve clearances are near the upper limit (as big as they can be without being out of the range) starting will be easier. This is especially important on the exhaust side.

Also, give it a little time, it should get better as it breaks in.

Thanks guys...all good sugestions. I'll ride it again this weekend, if it's no better, I'll bring it in & have them check tolerances.

Dont forget the plug wire. Some have been broken resulting in hard starts.

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