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checked my valve clearance today on my 07 450x because i thought my topend sounded a little extra noisy on my last ride. what i found surprised me but didn't at the same time. my intakes were loose instead of tight. makes sense because there seemed to be more noise, but i thought these clearances were supposed to get tighter instead of looser due to the valves deforming into the seats. the last time i set the clearance i had left them a tiny bit loose because the next shim size made them too tight. i expected they would wear into spec but now i check and they are even looser than i left them. what would cause the clearance to get looser? wear on the buckets? one was at .007 and the other closer to .008. oh almost forgot, the exhausts were spot on they have never changed. my shim kit has shims in .05mm increments, according to my conversion app that's .002" increments so one size thicker shim should get me right back in spec. this sound right?

Did you measure your shim to see that it didn't wear? weak springs maybe? Ken or one of the other experts on here will have a good idea of whats up. But I'm also interested in finding out what would cause intake valve clearances to increase.

you have to measure each shim...don't take the printed size as valid. then use our shim calculator to determine which size you need to replace the shim with. measure the new shim even if is is new.

ken