Running lean after valve adjustment?

[cuong-nutz]

Odd thing is my valves were out of spe but I needed thicker shims. I though they were suppose to get tighter. Adjust cylinder 1 to 1T and 2 at 2T lobes facing away from each other. Checked valve lash afterwards and rightmost intake valve was really tight getting in the .153 gauge. I did install a crank case breather. I'm blowing fireballs out my exhaust. It's cool but this does not feel right.

[Motofool]

I assume that you are sure of your cam timing being correct (verified chain has not jumped teeth) and of you being using a metric gauge.

Inlet 0.15 ∼ 0.24 mm (0.0059 ∼ 0.0094 in.)
Exhaust 0.22 ∼ 0.29 mm (0.0087 ∼ 0.0114 in.)

Yes, the clearance should get smaller with miles, exhaust's at a higher rate than intake's.

Valves should not influence the quality of the fuel mix, just the timing and volume of engine's breathing.

Fireballs out of your exhaust may mean two things:

1) The mix is too lean and the flame propagates so slowly that is still alive when the exhaust valves are opening.

2) Exhaust valves timing is so advanced that flames get uncovered way before the work stroke has finished.

I would double check timing of cams respect to crankshaft.

[cuong-nutz]

I'll tear it down again when the bike cools down and recheck everything over. The chain did look kind of odd when I was buttoning it all up so it might have jumped a tooth.

the crankcase breather, made the bike even louder as the engine noise is more audible under the tank. I think I'm just going to plug it back up again.

Link to original page on YouTube.

[Motofool]

During the years, I have learned not to modify more than one thing at a time.

If something goes wrong, at least I know what it may be.

Note that the flame appears only when you close the throttle, which reduces the vacuum on the jets and induces a leaner mix.

It is always a good thing to service and reset the cam tensioner while the chain is visible.

That way, one can be sure that the tensioner is pushing on the guide and that the chain is working under tension.

Never rotate the engine by hand in the wrong direction.

[cuong-nutz]

It's running good again now. Valves were out of spec, so corrected the shims and they're good. They were way too tight so the valves weren't closing all the way. I don't know how I messed up the specs the first time. All is good now