Valve Clearance Questions

[DannyBoats]

I'm doing my first Valve adjustment and have a couple questions. The bike is a '79 550L with 24,000 miles. I've put 6,000 on her.

Only a couple are in-spec, but the rest have ZERO clearance. I was expecting too much clearance and I'd have to shim up. It sure would be easier to figure out what size I need. Is this normal?

I had to stop working on her before I got to taking out shims, and I thought I might get some pointers on how to proceed. I have some shims around, but am having trouble finding them. Living on a sailboat gets crowded, especially with 2 GS's and several other hobbies.

Thanks in advance for your replies!

[tkent02]

Usually they get tighter as they wear, this is normal. Try this, with the cam in the position specified in the Suzuki Service Manual, see if you can rotate the shim in the bucket with your finger, if you can spin it there is at least SOME clearance, one size smaller shim should put you in the acceptable range, which is really .03mm to .10mm. The book says .03mm to .08mm, but .10mm is just fine. If it won't spin, there is NO clearance, maybe even negative clearance, you can go two sizes smaller and not be over .10mm. Always check everything again once you make your shim changes, the shims are not really all that accurate in their thicknesses.

[BassCliff]

Hi,

Check out this PDF file.

Valve Adjustments (8 Valve)

If the clearances are too small then slip in the next smaller size shim and re-measure. (DO NOT spin the motor if any shims are missing!) The first time I did the valve adjustment on my bike I had to swap 5 shims, some of them had to go down two sizes. I don't think the previous owners ever adjusted the valves.

These 8 valve motors tend to tighten up over time. But once you get them well adjusted they will stay fairly stable. I've had to swap only three shims in my last three valve checks.

Z1 has the best prices on shims, about $5.28 each. Don't buy a whole kit, just the ones you need. Inventory the shims you have so you know what sizes to order. Then maybe order a few smaller ones for the future. There's also a Shim Club in the forum for trading shims. See the Services section.


Thank you for your indulgence,

BassCliff

[DannyBoats]

Will do. Thanks for the help!

[philosopheriam]

If the clearances are too small then slip in the next smaller size shim and re-measure. (DO NOT spin the motor if any shims are missing!) The first time I did the valve adjustment on my bike I had to swap 5 shims, some of them had to go down two sizes. I don't think the previous owners ever adjusted the valves.

As a testament to what BassCliff said, my buddy's 1982 GS650G had never had a valve adjustment done in almost 24000 miles. I had to drop two shim sizes down on four of the valves to get them within spec.

Chances are that if you can't fit a .03mm feeler gauge between the cam lobe and the shim, you may have to go two sizes down on that valve.

If you go two sizes down and find that your clearances are on the high end, .08 to .1 mm, that's fine. It's better to have a valve on the high end than on the low end.

[Steve]

If you would like some help with the math and a place to record your results, follow the suggestion at the end of my sig.

.