GS850G valve adjust newbiew questions.

[Big_Z]

Hello,
I'm trying to get a 1980 GS850G running. I checked valves using the howto on BassCliffs webpage and I have some questions.

After I got the cover off there are actually 8 valves that need to be checked? I was expecting 4. There are sections labeled A, B, C, D each have two lobes/shims?

Will I have to remove all the shims that are in the bike currently because I can't tell what size they are and I need to know that to do the math for the adjustments?

Also BassCliffs guide shows the lobe pointed forward for testing but the clymer manual I have says the lobe should be pointing upward? Can I get some clarification here?

Thanks guys!

Z

http://www.thegsresources.com/_forum/editpost.php?do=editpost&p=1003276

 

[TheCafeKid]

You have TWO valves per cylinder. thats a total of 8 valves. one intake, and one exaust on each cylinder. Its a good idea to inventory your current shim sizes, so you have an idea of what you'll need to order NEXT time you do a valve adjustment, so you dont have to wait on shims like you will this time. Also, DO NOT remove all the shims at the same time, and DONT turn the cams without a shim in every bucket or you'll scratch the crap out of the cam lobes. Some guys do it one way, but the MANUAL calls for you to turn the cams in a specific way so there is no load on ANY of the valves on that particular cam so you get accurate measurements when using your feeler gauges. If i recal correctly, it calls for you to rotate the cams to that the lobe over cyl 1 is flat, and over 2 is vertical or something like that. Id have to look at the head in order to tell you, its been a lil while since ive adjusted an 8v motor... However, either way is OK, as your measurements wont be thrown off by but maybe .01mm and if its that close, you need to change it anyway IMO...

 

[BassCliff]

Hi Mr. Big_Z,

Please read the entire guide on my website. There is quite a bit of supplementary information at the end of the guide. Let me add to what Mr. TCK has advised...

After I got the cover off there are actually 8 valves that need to be checked? I was expecting 4. There are sections labeled A, B, C, D each have two lobes/shims?

Yes, each cylinder has an intake valve and an exhaust valve. Perhaps you'd like to do a little research on the theory of a 4-stroke internal combustion engine?

http://auto.howstuffworks.com/engine1.htm
http://www.small-engines.com/4cycleth.html

I'm not sure what you mean by "A, B, C, D sections" unless that is how it is referenced in the Clymer manual. The method in the Clymer manual differs from the method in the Suzuki Factory Shop Manual. Did you download a Suzuki Shop Manual from my site? Please help yourself. I've always relied on the Suzuki method.

Will I have to remove all the shims that are in the bike currently because I can't tell what size they are and I need to know that to do the math for the adjustments?

Hopefully, if the numbers haven't been worn off, the sizes will be printed on the shim itself. The sizes should be on the bottom of the shim away from the lobe so that they don't get worn off, but quite often a previous owner or mechanic will install the shim with the size up and it will get worn off. Use a digital caliper to determine the sizes in this case.

Also BassCliffs guide shows the lobe pointed forward for testing but the clymer manual I have says the lobe should be pointing upward? Can I get some clarification here?

Pointing each and every lobe up before you measure that valve clearance can cause the other lobe on that side to start pushing its valve down. This may throw off your measurements. Using the Suzuki factory method, the cam is "unloaded" and more accurate measurements can be taken. Exhaust lobe #1 is pointed forward when measuring exhaust #1 and #2 clearances. Exhaust lobe #4 is pointed forward when measuring exhaust #3 and #4 clearances. Intake lobe #1 is pointed up when measuring intake #1 and #2 clearances. Intake lobe #4 is pointed up when measuring intake #3 and #4 clearances.

Thank you for your indulgence,

BassCliff

 

[Steve]

After I got the cover off there are actually 8 valves that need to be checked? I was expecting 4. There are sections labeled A, B, C, D each have two lobes/shims?

Yes, there are EIGHT valves, as CafeKid mentioned. The "sections" that you mention are actually just labels for the cam caps.
If you ever have the need to remove them, they MUST go back where they came from, the letters tell you where they were.

Will I have to remove all the shims that are in the bike currently because I can't tell what size they are and I need to know that to do the math for the adjustments?

Yes, you will need to remove the shims to see what size they are, but before you do that, you will need to measure the clearance between the shim and the cam.

To help you with all the math, send me an e-mail request (click on my name for e-mail address info) and I will send you an Excel spreadsheet that will help you with the math to determine what shims you need and will help keep track of your shims from one time to the next.

Also BassCliffs guide shows the lobe pointed forward for testing but the clymer manual I have says the lobe should be pointing upward? Can I get some clarification here?

Believe it or not, they are both right. Read the manual carefully, it says to start with the exhaust lobe for #1 pointing forward and the lobe for #2 pointing up. Without moving the engine, measure the clearances for exhausts 1 & 2. Rotate the crankshaft 180 degrees so that the lobe for exhaust #4 is pointing forward and #3 is pointing up, measure the clearances for exhausts 3&4. Rotate the crank another 180, now the lobe for intake #1 will be pointing up, the lobe for intake #2 will be pointing back. Measure intakes 1&2. Rotate the crank a final 180 so the lobe for #4 intake is pointing up and #3 is pointing back, measure the clearances for intakes 3&4.

To check your shims is little more involved. You can use the official shim tool or the zip-tie method, but one way or another, you need to hold the valve down so you can remove the shim to examine the number that is printed on the bottom side. Sometimes the number is worn off, you will need to measure the shim with digital calipers. Record the size of the shim (this is where my spreadsheet works very well), move on to the next shim until you have checked them all. Now you can compare the clearances with the ones that need adjustment to see if you can move any of the shims around to minimize buying shims.

It's not really all that hard, might take you a couple of hours the first time through. Later, you will have it down to about 45 minutes.

.

 

[BassCliff]

It's not really all that hard, might take you a couple of hours the first time through. Later, you will have it down to about 45 minutes.

Ha! The first time I adjusted my valves it took me about 4 hours. Now it takes me longer to remove the seat, tank, and valve cover than it does to measure clearances and swap shims.

I'm sure Mr. Steve can do it in his sleep.


Thank you for your indulgence,

BassCliff

 

[Steve]

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[Big_Z]

Thanks guys. I will recheck my measurments and pull the shims and see where I am.

 

[Big_Z]

OK, got my shims out and checked sizes. also remeasured all the clearances. I have some questions about how to read the measurements.
here are some numbers i got.

ex 1 .051 fit, .063 did not fit
ex 2 ? , .038 did not fit (smallest size)
ex 3 .063 fit, .076 no fit
ex 4 .051 fit, .063 no fit

in 1 .09 fit, .102 no fit
in 2 .051 fit, .063 no fit
in 3 .051 fit, .063 no fit
in 4 .178 fit, .203 no fit (!!!)


so based on those measurements it looks like Ex2, In1, In4 all need adjustment and the rest are OK?

 

[TheCafeKid]

OK, got my shims out and checked sizes. also remeasured all the clearances. I have some questions about how to read the measurements.
here are some numbers i got.

ex 1 .051 fit, .063 did not fit
ex 2 ? , .038 did not fit (smallest size)
ex 3 .063 fit, .076 no fit
ex 4 .051 fit, .063 no fit

in 1 .09 fit, .102 no fit
in 2 .051 fit, .063 no fit
in 3 .051 fit, .063 no fit
in 4 .178 fit, .203 no fit (!!!)


so based on those measurements it looks like Ex2, In1, In4 all need adjustment and the rest are OK?

Yikes! Intake four sounds like it might have a heavy carbon/oil deposit build up on the back side of the valve not letting it come back all the way, or whomever adjusted those valves last was a complete idiot! Thats WAY WAY too loose. Spin that sucker up to redline and it might have lifted that shim out of the bucket and spat it around your head. That, in case you didnt know, would have been REAL bad. Intake one is a lil loose, but .09mm is IMO perfectly ok to run, as it will only tighten with wear. That is provided its not stuck open from carbon too..Depending on your sizes, you MIGHT be able to swap some of the shims that are well over tollerance around to places that are not, or tighter, and save a few bucks on shims. But you WILL need to order at least ONE for exhaust 2... Assuming it simply needs the next smaller shim, it might need to go 2 sizes smaller. Perhaps if you posted up the shim size from EX 2, someone might have a smaller size they can send you to try out, or at least get a more accurate measurement from. If your smallest gauge wont fit, its hard to tell whether or not the next smallest shim is the one you need. I bought an 8v 750 motor off ebay a year or so ago, and all the valves were so tight i had to pull the head because i was afraid they were cooked. Fortunately they werent, the one nice thing is at least on the intake side, generally once they get to the point where they arent closing at all, its highly likely the bike simply wont start anymore, or run for any length of time. And, on the intake side, its much cooler and less likely to toarch a valve if they're getting stuck open.

 

[BassCliff]

Hi,

Are you working with millimeters or inches? Do you have all of your decimal points in the right place? Those are some surprising numbers.

In inches; you want your clearances to be between .001 and .003 inches, that's between one and three thousandths of an inch.

In millimeters; you want your clearances to be between .03mm and .08mm. It's much less confusing (to me) to use a metric feeler gauge set with increments of .01mm (.04mm, .05mm, .06mm, .07mm, .08mm, etc).

Providing the numbers you gave are in millimeters, I concur with Mr. TCK. Everything is in spec except for that #4 intake (Yeeeow! Way loose!) and perhaps the #2 exhaust (perhaps a little too tight).

Please keep us informed.

Thank you for your indulgence,

Cliff