Valve clearance question

[ccs]

Hey Eveyone;

I just checked my valve clearances for the second time. The clearance has increased on 3 of the exhaust valves and 1 of the intake valves. The clearance has been reduced on 1 intake valve (from .05mm to .04mm).

The 3 exhaust valves are at .08mm (the upper limit).

I have read where some keep the exhaust valve clearance towards the upper limit (.08mm) and am wondering if I should change shims on these valves or not (The #1 exhaust is at .04mm).

TIA.

Charles...

[spchips]

1) Valves are affected a lot by temperature. Make sure the engine is dead cold (24 hrs plus) before measuring.

2) It is generally better to aim on the high side of the valve clearances. This is most definitly true for the 8 valve shim and bucket motors, as the shims are a pain. On the 16 valve motors, it's easier to adjust the rocker arms, so you could get away with being low or in the middle. Valves wear tight, until eventually the valve no longer closes all the way. so if you're lazy or don't know when it'll get done again, loosen them up.

[Nessism]

I wouldn't mess with them if they are in spec. The valve train on the GS bikes is very stable and don't loose clearance very quickly. You will be fine till the next change interval.

[ccs]

Valves wear tight, until eventually the valve no longer closes all the way.

Don't understand this -- seems they would wear looser -- which is what mine have done:

#2 exhaust from .05mm to .08mm
#3 exhaust from <= .04mm to .08mm
#4 exhaust from .07mm to .08mm

#1 intake from .07mm to > .10mm

What's up with this?

Charles...

[Nessism]

Clearance typically goes down on the 8 valve engines as the valves reseed into the head. 16 valve engines with the rocker arms may not follow this trend though.

One thing that can lead to inconsistent measurements is how you take them. The cam must be in the factory recommended position before you check the clearance or the adjacent valve may skew the cam within the cam journal clearance and cause inconsistent lash measurements. So the question is how did you check the clearances?

[ccs]

The cam must be in the factory recommended position before you check the clearance or the adjacent valve may skew the cam within the clearance and cause inconsistent clearance measurements. So the question is how did you check the clearances?

In the factory recommended position, AFAIK. (I've got a Haynes manual and rotate the crankshaft so that the cam lobes are in the "B" position as shown in the manual.)

However, I do seem to get some inconsistent clearances.

Charles...

[Steve]

However improbable it might be, it is conceivable that there was a speck of carbon holding the valve open just a tad in the second measurement. I have been known to turn the engine over a few times with the starter after adjusting the valves to make sure all the valves are seated properly, then check them again.


.