Shimming on a top-end rebuild?

I have an '05 CRF250R that's been torn down for almost a year now due to a cracked head. I've been extremely busy and haven't had a chance until now to get a new head and I went ahead and got new valves to put it all back together (it was needing them). Since it's been so long I've actually forgotten the specs for the exact size shims I had in (though I'm sure that wouldn't matter anyway due to new valves), but anyway my question is pretty simple:


When adding shims to a new build like this, is there a specific size I should start with or do I just need to take a guess and put it back together and measure from there to make adjustments?


Not a huge deal if I have to do it that way, but putting the rocker and cam back in, torquing it down, etc., and pulling it out over and over again seems very tedious.


Thanks ahead of time.

If you have a shim kit it will be easy, and cheaper. What I usually do is put 2's in and measure from there, and usually the second one I put in is the right one

Okay, I do have a shim kit. What if it's too tight and I can't get a feeler gauge in there? Surely it won't be, but I guess if so I just bump it down a size or two and try again?

Yup, you got it

Awesome, thanks a ton.

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