06 crf250r Engine rebuild please help!

OK my 06 crf250R isn't starting up easily anymore It also seems to have lost a good amount of compression. I've been looking through the forums and it looks like my valves might be tight so ill either be doing a shim kit or new valves completely. Any suggestions on the types of valves I should put in or if the shim kit will work okay? I also will more than likely be replacing the piston in it while since the engine will be already apart so any suggestions on that also? I appreciate all of the help and any tips or tricks you might have for me because this will be my first time taking apart an engine. Also a list of tools and equipment that i'll need would be much appreciated too.:thumbsup:

Before you do anything, you really need to get a shop manual.

First thing you need to do is determine whether you have the stock titanium valves or stainless steel valves. My bet is they're the stock valves. Shimming them is a waste of time. You might want to go to the stainless steel valves being that they are much more durable. You will need the valve seats cut also. Aftermarket pistons like Wiseco, JE and Moose are very good quality pistons. I would suggest replacing the timing chain also.

Torque wrench is probably the #1 tool you need. Flywheel puller if you plan on changing the timing chain.

Thank you very much for the input do you have any idea how much this should cost me?

Rough estimate:

Pro-X SS valves with springs- $100 on e-bay

Intake valve grind- $30 each at a local machine shop

Aftermarket piston- $150-$250 depending on the brand you choose

Timing Chain- $50

Again, these are rough prices.

what are your valve specs right now? have you ever shimmed them before? how often do you ride and what type of ridding do you do?whats your budget?

Thanks for the prices, :thumbsup: ANd no I haven't tried to shim them but from what I've read and heard it doesn't look like it would be my best choice because it seems like they don't hold up. I don't know what my valve specs are yet. I haven't taken apart the engine yet because of my busy schedule and I'm saving that for the weekend. And I just went to a track the first time and that's when my valves gave out, before that was all trail riding. I'm not positive that the valves are the problem but from all the signs I'm getting (low compression, hard to start, and starts easy when hot) it looks like the valves are the problem.

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