Valve adjustment shims

[GS750GUY]

I think it may be time to check the valve spacing on my 78 GS750EC.
If needed, where can I get valve adjustment shims?

Also, would like to know from the experience of other GS family members......
Even though the maintainance catalogs recommend LOOKING at your points and condensors and valve spacing every 3000 miles how many of you out there have ACTUALLY had to REPLACE points & condensors and do valve work adjustments every 3000 miles? What is the longest number of miles some of you have gone with a bike like mine where you finally actually had to replace points, condensors and adjust valves because performance was suffering?
It's hard to imagine the need to do these things EVERY 3000 miles.


Thanks!
GS750GUY

[TheCafeKid]

Z1Enterprises will have your full range of adjustment shims...good prices too..Dealer will have them also, but in my experience they have to order them anyway and they'll charge you around double what Z1 will.

[Nessism]

If you get to the point where the performance of your engine is affected by mis adjusted valves, you most likely did permenent damage to the engine (burned valves).

Frankly, I think 3000 miles is excessive but then it depends on how hard you ride the bike and what the valve clearances were in the first place. For example, if you had a valve on the tight end of the specification range and then rode the bike hard for 3000 miles, it very well may now be out of spec on the tight side now (valves in GS bikes typically get tighter with time). Write down the clearances and if you are on the tight side, particularly on an exhaust valves, you are gambling if you extend the inspection interval.

Good luck.

[80-81, GS 1100]

If you get to the point where the performance of your engine is affected by mis adjusted valves, you most likely did permenent damage to the engine (burned valves).

Frankly, I think 3000 miles is excessive but then it depends on how hard you ride the bike and what the valve clearances were in the first place. For example, if you had a valve on the tight end of the specification range and then rode the bike hard for 3000 miles, it very well may now be tight now. Write down the clearances and if you are on the tight side, particularly on an exhaust valve, you are gambling if you extend the inspection interval.

Good luck.

I agree with 3000 miles seeming excessive for a bike with shims. Are
you sure the interval wasn't check it at the first 3000 and then larger
intervals after that? I don't know much about that model but
why would they use shims if its 3000 miles? Shims usually require
adjustment less than screw adjusters......

[bwringer]

Actually, the manual for my GS850 (nearly the same engine as the early 750) calls for an oil change every 2,000 miles and a valve check every 4,000.

I whip my 850 like a rented mule, so yes, I do check the valve clearances (and change the oil) on schedule. About every second valve check, I'll need to change one or two shims.

The valve clearances needed (.03mm to .08mm) are vanishingly small compared to many other engines, and they tend to decrease over time (exhausts change a bit quicker than intakes). So you won't hear any sort of valve clatter as a warning sign.

It's very common for GS owners to neglect checking valve clearances, but I can't understand why. Adjusting shim valves is quite simple and straightforward, and if you invest $40 once in a silicone RealGasket valve cover gasket and breather cover, you won't ever need another gasket.

If you let this go, over time, a few valves will get tight, and the bike will run worse and worse. Tight valves have a pretty bad effect on carburetion, even though compression will still test OK. If it gets to the point where compression is affected, you've likely burned a valve.

Just to give you a real-life example, a friend's GS850 was running like total poop last summer. Unbeknownst to me, it had been 8,000 miles since the bike had had a valve clearance check. On inspection, two valves were tight -- no clearance. One needed a shim one size smaller and one needed a shim two sizes smaler. Problem solved. It doesn't take much to upset the carburetion badly.

Once you check them and know where the clearances are, you might be able to stretch valve clearance checks to 5,000 miles or so, but I wouldn't ever push it to 6,000 personally, even if you ride like a little old lady.

Get a valve shim tool, a set of METRIC feeler gauges (BikeBandit sells a nice set that goes down to .03mm), a Realgasket, and do it yerself. You can get the tool and whatever shim you might need from Z1enterprises.com or crc2onlinecatalog.com (after a while, you'll build up a collection of spare shims). Hit up realgaskets.com for the re-usable lifetime valve cover gaskets.

All this will cost less than the $150 most shops would charge you to let one of their shop monkeys screw it up. And to really put the polish on, get a Carbtune carb synchronizer with the savings from your next valve check.

[BassCliff]

A happy valve is a slappy valve

Mr. GS750GUY,

I adjusted my valve clearances at 18,500 miles, about 4500 miles after I bought the bike. I don't know if they had ever been done before. I swapped out 5 shims, 2 of them had to go down 2 sizes. It made a world of difference in how the bike ran. I'm glad I didn't wait any longer. It is pretty easy to do and I plan on doing it somewhere close to the factory recommended schedule, at least twice a year. Mr. Steve's spreadsheet will help you figure out and keep track of the shim sizes you'll need. That way you don't have to buy a complete "kit" with a lot of sizes you'll never use. If you'd like, check my little website (link in my sig) for a pictorial guide to valve adjustment. But please refer to your factory manual for specific information on your bike.

Thank you for your indulgence,

BassCliff

[Steve]

Thanks for the mention, there, BassCliff. 8-[

GS750GUY, if you would send me an e-mail (just click on my name for the info), I will send you a copy of the spreadsheet that BassCliff mentioned.


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[GS750GUY]

[quote=bwringer;726208]Actually, the manual for my GS850 (nearly the same engine as the early 750) calls for an oil change every 2,000 miles and a valve check every 4,000.

What year is your GS850? If it is the 83 that you show in your list of bikes, I thought Suzuki went to hydraulic valves in the early 80's.

My Haynes manual shows 3000 miles for my 78.

I appreciate your input!

GS750GUY