YZ timing/increased engine noise

I just changed to YZ timing on my '00 WR. I rejetted to 175MJ/48PJ, stock DRS needle #3 clip. Also cleaned out the carb at the same time.

It started up first kick and immediately noticed increased engine-valve train noise (not exhaust). I adjusted the pilot screw just after warm up to around 1 3/4 out which seemed to smooth it out a little. The bike runs great, no popping, backfiring, hesitation, or surges-just raw power everywhere. The noise sounds like the cam chain is loose, however before I put back on the top cover, I rotated the engine several times and the chain appeared as tight as before in all spots during the revolution.

My question is this: Is is normal to have a little more valve train sound when switching to YZ timing? Not much more, but enough to raise a concern about it.

Thanks everyone, you guys are GREAT!!


Maybe you want to reseat the cam chain tensioner, like the manual says.

I think you wind it up and then bolt it in, then it unravels. Maybe the thing can get stuck and not unwind.

Just a possiblity based upon your description.

John I'm glad you mentioned this. I did have a problem with this.

I wound it up and locked it before removal. However upon removing it with some force, it unlocked. Upon reinstalling it, I had to wind it up, hold it wound, then tighten the two bolts.

Again I took note of the chain tension before the job and after. The tension seemed the same (tight, with maybe 1/8 of give if that).

I think I'll lock it again, remove it, reinstall it, then unlock it just to be sure though. Thanks for the tip.

Another option may be some dirt got in there, but I was VERY careful about that and cleaned above the engine really well before starting the job.

Another thing that may be of concern in the half-moon clip the cam rotates around in betwen the cam and cam cap. I may have put it in backwards, which is probably OK, but the wear existing pattern may be causing this noise.

Again, it's not real loud or alarming like something is dreadfully wrong, just want to make sure my beast is in tip-top shape


I also noticed a bit more noise after switching to YZ timing. I could find nothing wrong but was wondering if maybe the noise was actually coming from the clutch basket.



If you haven't laid it down, you're not riding hard enough!

I went for ride last night for about an hour and the noise seemed to smooth out after re-adjusting the pilot jet. However there is definitely more vibration felt in the bars now-my hands were tingling after about 45 minutes of trail riding. This may be due to loose fasteners, but I did anti-seize and torque every last bolt to specs.

What about vibration? Anyone experience a little more vibration after switching to YZ timing-especially low RPMS? I didn't notice this at first because my test ride was only 10-15 minutes. I say low-rpms because that's where I felt the most and that's where my front fender was shaking the most. At mid range and higher, it seemed as smooth as ever.

I did notice the 3 times I have started it that it starts right up the first kick cold, and first kick when hot (with hotstart). With WR timing, 1-3 kicks was more like it cold. I cleaned the carb really well, this probably had something to do with it.

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