Shim gauge position question

[ty998]

In my Clymer manual it says to have the lobes pointing straight up and then check the clearances (I am assuming for all lobes, it doesn't say otherwise). In BassCliff's tutorial (PDF) he outlines checking some of the clearances with the lobes pointing sideways. Is this simply because in this position both of the lobes pointing up and sideways place no pressure on the shim and can be checked without further rotating the cams?

May be an obvious question. I just don't wan to mess this up. Thx

[mike_of_bbg]

It's not just the one cam, but the one next to it, too. The particular positions pointed out in BassCliff's guide (which should be in your factory manual as well) puts that half of the camshaft in a neutral position as you check. That keeps it centered in the bearing surfaces.

[BassCliff]

Hi,

The guide on my website uses the factory method and makes for more accurate measurements because of the reasons Mr. mike_of_bbg state. The illustrated lobe positions unload the cam shaft on that side for the measurement of both clearances.

That Clymer's method has been the source of much confusion.

Thank you for your indulgence,

BassCliff

[ty998]

Thx for the reply 'mike of bbg.

BassCliff, thx for the reply. Also I greatly appreciate your website and your effort to document the maintenance tasks. It takes a lot of patience and confidence to document a task as you move through it.

[Steve]

I depends on what bike you have. (Hint, hint)

If you have a twin, with only one cylinder on each side of the cam chain, pointing the lobe away from the valve is fine. However, if you have a four, the lobes should be pointed about 45 degrees away from the valve, but so that BOTH lobes on that side of the cam are at 45 degrees from their valves. When in that position, check BOTH valve clearances without moving the cam.

Easiest to start with the left side of the exhaust cam. Position #1 lobe forward, #2 will be straight up. Check EX 1&2. Rotate the crank 180 degrees (1/2 turn), you will find that Intake 1&2 will be lined up, but those lobes will be backward and up. Check both, IN 1&2. Rotate crank another 180 degrees, check EX 3&4. Rotate crank a final 180 degrees, check IN 3&4.

.

[ty998]

I depends on what bike you have. (Hint, hint)

If you have a twin, with only one cylinder on each side of the cam chain, pointing the lobe away from the valve is fine. However, if you have a four, the lobes should be pointed about 45 degrees away from the valve, but so that BOTH lobes on that side of the cam are at 45 degrees from their valves. When in that position, check BOTH valve clearances without moving the cam.

Easiest to start with the left side of the exhaust cam. Position #1 lobe forward, #2 will be straight up. Check EX 1&2. Rotate the crank 180 degrees (1/2 turn), you will find that Intake 1&2 will be lined up, but those lobes will be backward and up. Check both, IN 1&2. Rotate crank another 180 degrees, check EX 3&4. Rotate crank a final 180 degrees, check IN 3&4.

.

Bike is a '81 Suzuki GS650 GX

[BassCliff]

Hi,

Bike is a '81 Suzuki GS650 GX

Feel free to put that in your sig file. Then you don't have to worry about forgetting to mention it in your posts.


Thank you for your indulgence,

BassCliff