Installed the new cam on my 98 WR400, measured up valve clearance and I had a whopping .90mm clearance on the left valve and approx .45mm on the right. Measured cold. I didn't measure the clearance with the original cam before I removed it..Doh. I presume I am getting a 'loose' valve? Is it possible I have a 'sticky' valve and the clearance is not as big as I may think, just I am measruring it in the stuck position. Should I be worried or should I just slam the correct shim in there (from 175 to 235). I checked the tolerance about 1 yr ago and it was well within the norm. Now the clearance difference seems huge to me. Cam shaft cover bolts torqued down to correct torque (10nM) One last thought, I have been getting intermittent performance wobbles at constant speed. I'll be humming along and then the motor starts to sputter, but still works...mostly. That lasts a couple of minutes then clears up for a while and then maybe next time I ride the same thing. The more I write the more I think a top end service is in order. What do y'all think ? Mechanically I can do the CAM shaft switch without referring to the manual. Is a top end teardown much more difficult? Do I need any special tools? How long does it take ?