Crf450r Shimmed Valves

hey everyone. im looking at an 07 crf450r. the guy said that he is sure the owner who had it before him shimmed the valves in 09. just wondering what you guys think and how long you think it would be good for. it was not raced and he said it now has 21 hours on the bike. i just put new valves in my crf250x(im selling) and do not want to deal with fixing them for another while.


id check them before riding. it varies how long it takes before they go outta spec. i shimmed mine, rode 80 hours and checked again and they were all stilll within spec... theyve got like 90 hrs now since last shim and starts and runs good. some people say they have to shim after 20 or less hours. if the bike starts easily and runs good theyre most likely fine but it never hurts to check

Okay. So does it depend on how hard you ride it and how often you change the oil and filter? And also. are 450's easier on valves than 250's because they dont rev as high?

450 aren't as hard on valves as a general rule but rider and conditions play a big part.Oil changes have no effect on the valve sealing surface at all.If you new what size shim was in the bike you could get a rough idea of the valve wear but thats not an option.If the bike looks clean with low hours it's probably okay.

Might as well check em so you know how to do it. You will be doing it again anyways.

I'd look at the bike's condition as a "whole" if I were interested. Regardless of what the prior owner says about the valves I would include a valve job in my "own" post purchase expectations not the seller's. If you buy a used CRF and take the word of the seller you will find yourself very disgruntled with them when you get back from your first ride finding out that the bike needs valves. I like to start off knowing about the valves by visual inspection and that ain't gonna happen until you buy the bike (in most cases).

With 21 hours on the bike it should be in good condition. Look for abuse and make your determination to purchase based on the whole bike condition vs price. Always talk down the asking price but know that you will be responsible for the valves post purchase.

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