[Stottyc16]

Hey everyone! I have a 2006 CRF250x that I have had constant valve problems with since I bought it used last year. I had to re-shim the intake valves almost every 3-5 hours. However I never had any issues with my exhaust valves. I think I found out online that this was due to the intakes being titanium and the exhaust being stainless steel. When I found this out I decided to do the stainless steel (Kibble White) "upgrade" to the intakes for a more "reliable/less maintenance" approach. Also my intakes were razor sharp, I could almost shave with them, so they needed replacing anyways. Well not even 10 hours into the stainless steel intake valve swap and my camshaft is completely destroyed. The auto decompression weight snapped, and the cam buckets now look like bowels. There are two, possibly three reasons why I think this could have happened. 1) The springs (yes 2 per valve) provided for the steel "upgrade" were too heavy causing excessive wear on the cam. 2) For some reason oil wasn't getting to the cam (too many wheelies I suppose jk) causing metal on metal wearing down the cam crazy fast. or 3) My cam chain could have skipped a tooth on the cam sprocket messing up stuff. I don't think it was option three because it ran just fine, like factory, where I've timed it wrong before (skipping just one tooth on accident) and the thing wouldn't start. I guess before I throw $300+ at the thing for repairs, I'd like to gain some insight and knowledge from you guys out there who have been where I am, or at least can help me figure out whats wrong before I drop more money to wreck another cam. Any help is much appreciated!

[JimDirt]

Welcome to the site !!

From what you described , I am going to say the oiling issue is the problem ..... The question is , is WHY there is a oiling problem

I am wondering if when you put the tower back together that you did not get the cam bearing in place ..... or ...... that you removed the flywheel and in doing so , got the cap on the puller too tight and smashed the brass end at the end of the crank which is a oiling seal , in which case , the crank would now be toast ...... I am assuming that you had a reputable shop cut the seats and measure the depth so the shims would fit , etc. ??? , if the springs were matched with the valves , then there should not be a issue with the tension being too stiff ..... not possible , and that would not cup the buckets , the oil is the cause of that , so your first task will be finding out why the top end lost oil ..... that above all needs to be addressed before anything else is replaced , otherwise you will fire it up and destroy all the next batch of new parts ......

Stainless valves (and springs) would not cause any of these issues , you should get tons of hours on them without worry or adjustment , the reason you were adjusting yours so frequently is because the valves were worn out , and once they start to move , its only a matter of time before you run out of shims to fit ...... Unfortunately , no matter what , you will be replacing more parts ..... but as mentioned , you must find the cause of the lack of oil first ........