Valve Check Question

[ChrisK]

It came time to check my valves. The four clearances on the vertical cylinder are within spec. The two clearances on the horizontal intake are within spec. Then I tried checking the opener clearance on the horizontal exhaust valve and my smallest feeler gauge won't even slide in - that gauge being .0015" or .038mm. I have the dots on the flywheel sight glass lined up for TDC and I can feel the horizontal piston at the top of the cylinder with a screwdriver.

Is this common? Does it just mean I need to sand down the opener shim? If so, how much would you suggest sanding off initially? I suppose logic would say to sand off the amount of the spec, which IIRC is .004"?

Thanks in advance for the help! 

[scooterd145]

can you spin or rotate the shim using your fingers?

[Speeddog]

It came time to check my valves. The four clearances on the vertical cylinder are within spec. The two clearances on the horizontal intake are within spec. Then I tried checking the opener clearance on the horizontal exhaust valve and my smallest feeler gauge won't even slide in - that gauge being .0015" or .038mm. I have the dots on the flywheel sight glass lined up for TDC and I can feel the horizontal piston at the top of the cylinder with a screwdriver.

Is this common? Does it just mean I need to sand down the opener shim? If so, how much would you suggest sanding off initially? I suppose logic would say to sand off the amount of the spec, which IIRC is .004"?

Thanks in advance for the help! 

What specs are you using?

Likely that the horizontal exhaust closer is way out of spec, correct that first, then re-check the opener.

It'll take you a long time to sand .004" off of an opener, best to buy (or trade) one that's nearer (or correct) size.

[ChrisK]

Yes, pretty easily

[scooterd145]

Why I ask this is because if it can spin but my .0015 will not fit I call it a .0005 and calculate from that. It has not failed me yet ;-) I am on the road until next week so I can't give you the changing spec.

[scooterd145]

FWIW I use the check the opener, write that down, push the fork check it again and do the math for the closer spec. May not be the method Speed does.

[ChrisK]

Speeddog, I didn't notice your reply before I sent my last reply. I'm using the specs in the Haynes manual.

Scooter I'm also using the method of measuring the opener, pushing the arm down, re-measuring, and doing the math to get the closer clearance.

So should I remove the closer shim and measure with a micrometer? Then proceed from there?

[Speeddog]

I don't have a Haynes manual, so I've no idea what they say....

Yes, measure the closer clearance, then measure the closer shim (better results with a tool and micrometer).

Then get and install the new closer shim, confirm closer clearance, then see what the opener clearance is.

Then fix the opener clearance.

[ChrisK]

The .0015 gauge won't slide into the closer either, but the shim will spin with a little effort. So can I assume the closer is just barely too big? So get a smaller closer, re-measure and then address the opener as needed?

[Speeddog]

So you push the closer rocker down, and you still can't get the .0015 gauge in?

[ChrisK]

Correct. It gets slightly easier to spin the shim, but not a whole lot.

[Speeddog]

Sounds like that closer is reasonable, but I'm suspicious something isn't correct.

Usually, if the clearances were set correctly, like .001" on the closer and .005" on the opener, then after a good bit of riding the closer could be .005", and the opener would be .001".

[ChrisK]

What wouldn't be correct, off the top of your head?

Should I just try to get the right size opener and see where I'm at?

[Speeddog]

I'd pull the belts off, as I normally do, and remove the opener shim just to make sure all I've got 'in the picture' is the closer.

Rotate the cam to the 'tdc' position.

Then push down on the closer, and directly measure the clearance between the rocker and the shim.

[ChrisK]

I'll remove the belts and opener and report back tomorrow.