88 xt600 valve adjustment and timing mark
 

Hi there!

While following the service manual to adjust the valves on my 88 xt600 I noticed that I could not line up the timing mark when the piston was at TDC. It was to the left of the case mark about 1/2" (if I recall). The bike has 20k miles.

I proceeded to adjust the valves (which were very out of spec) and the bike seems to run well. Good power. I also adjusted the decompression cable and now it's easy to kick with no scary kickback.

One new thing I noticed is blueish smoke from the exhaust which I don't remember seeing pre-valve adjustment. It's not thick smoke - it's barely noticeable.

My questions:
1. Is the T mark offset due to timing chain stretching? Is it time for a new chain (pun intended).
2. Is the smoking exhaust due to my valve adjustment? Could it be caused by the timing being off?

I'm planning on checking the timing next weekend, but I thought I'd get some opinions sooner.

Thanks in advance.

Edit: I forgot to add the spark plug is pretty black despite being fairly new. I'm guessing it's running rich. I have not modified the carb besides a thorough clean. I am not sure if the jets are stock. It has an aftermarket pipe.

welcome to HU XT


for valve adjustment, crankshaft needs to be only on the whereabouts of TDC, position is not that important. So most likely the valves were adjusted right.

Regarding cam chain stretch, it's really unlikely on a 20K miles bike. The chain cannot jump at tooth either so if it's running okay you don't have any timing problem.
if in doubt, post pics of the marks as you see them...

Regarding the blue smoke, it cannot be related to a valve adjustment job.
Dark plug? Try changing your air filter, could be the reason for the smoke too...

Read THIS or THIS your timing chain has not stretched.

Mezo.