Finally checked my valve clearances on 1985 GS450

[dennco2]

I have been slightly fearful of proceeding on this project .... but finally did it today. Not as bad as feared as I only have 4 valves to check ... and 3 are fine (within tolerance). Cylinder 1 intake has no clearance ... or at least I could not get my smallest feeler gauge in there .04 mm. I pulled out the shim and found it was marked at 2.75 mm. What size do you recommend for replacement ... 2.65 or 2.70?

Is the best method just to buy both on Ebay or some Suzuki shop?

BTW, I didn't have a shim tool, so loosened the cap bolts to the camshafts and lifted up to create the clearance needed. Cam chain was still in place on both sprockets. Saw that tip somewhere on this board I believe and hope there are no drawbacks to that method.

 

[chuck hahn]

I would go the 2.65. And search ZIP TIE METHOD for removal of shims.

 

[chuck hahn]

Or maybe someone can directly link some pics of the zip tie method. But all you do is get a thick heavy duty Zip tie and fold it in half. Then bend it at about an 80 degree angle about 3/4 inch up from the folded end.

Next you remove the plugs and watch down the hole as you rotate the crank with a wrench. When the intake valve opens you stick the end of the tie between the valve and the head. Keep turning till the valve traps the tie and this will hold the bucket down so you can remove a shim. Rotate the crank a little to remove the tie and do another valve....etc etc etc

 

[dennco2]

Or maybe someone can directly link some pics of the zip tie method. But all you do is get a thick heavy duty Zip tie and fold it in half. Then bend it at about an 80 degree angle about 3/4 inch up from the folded end.

Next you remove the plugs and watch down the hole as you rotate the crank with a wrench. When the intake valve opens you stick the end of the tie between the valve and the head. Keep turning till the valve traps the tie and this will hold the bucket down so you can remove a shim. Rotate the crank a little to remove the tie and do another valve....etc etc etc

Yes, I had that Zip tie Method posting saved on my favorites ... but forgot about it when needed. That method seems to also require a skill to fish around and feel for an open valve when it's fully opened? The spark plug hole is pretty tiny but it appears one can get a glimpse of the valve.

http://members.dslextreme.com/users/bikecliff/images/valve_tool_zip_tie.pdf

 

[chuck hahn]

You can see them with a flashlight..ive done it before i bought the bucket depressor tool.

 

[Steve]

I would NOT lift the cam to get the clearance necessary to change the shims. That might introduce a bit of slack in the chain, which the tensioner would be very happy to take up. The problem is that the tensioner is a one-way device. Once it takes up the slack, it won't give it back, unless you release it manually.

The zip-tie method is very easy. Just rotate the cam so it is fully opening the valve. You can then see the edge of the valve through the spark plug hole. Slide the end of the zip-tie under the edge of the valve, turn the crank one full turn to put the cam lobe away from the valve, remove the shim for examination.

There is no need to waste a lot of money on shims. If you want to build your own collection, Z1 Enterprises has the best price on shims, at just under $5 each. However, GSR has a Shim Club that will exchange shims with you.

.

 

[dennco2]

I would NOT lift the cam to get the clearance necessary to change the shims. That might introduce a bit of slack in the chain, which the tensioner would be very happy to take up. The problem is that the tensioner is a one-way device. Once it takes up the slack, it won't give it back, unless you release it manually.

The zip-tie method is very easy. Just rotate the cam so it is fully opening the valve. You can then see the edge of the valve through the spark plug hole. Slide the end of the zip-tie under the edge of the valve, turn the crank one full turn to put the cam lobe away from the valve, remove the shim for examination.

There is no need to waste a lot of money on shims. If you want to build your own collection, Z1 Enterprises has the best price on shims, at just under $5 each. However, GSR has a Shim Club that will exchange shims with you.

.

I went on Ebay and bought 5 shims for $25. They are all at 2.65 mm. I did not bother to inspect all the shim sizes in my engine ... only to check clearances. Now to wait several days before I get them and put everything back together again. I really love the gs450 for buzzing around town on specialized trips. I hate riding my other bike for the same purpose.

 

[Steve]

I went on Ebay and bought 5 shims for $25. They are all at 2.65 mm. I did not bother to inspect all the shim sizes in my engine ... .

We have said many, MANY times, "shortcuts are only an opportunity to do it over and do it RIGHT."

Unless your other bike is also a GS that uses shims, the chances of using FIVE 2.65 shims at the same time are exactly ZERO. Your bike only has four shims.

You really need to do your bike and yourself a favor. Check your clearances again, but also remove your other shims ONE AT A TIME and record their sizes. That way, when you get around to checking clearances again, you can have the proper shims ready. Clearances only get tighter, you will need the next thinner shim.

If your clearances now are on the looser side of specification, you might not need to change a shim next time, but if they are approacching the minimum spec, you will want the next shim ready.
If you are interested in having a handy place to record your clearances and shim sizes, take advantage of the offer in my signature.

.

 

[dennco2]

We have said many, MANY times, "shortcuts are only an opportunity to do it over and do it RIGHT."

Unless your other bike is also a GS that uses shims, the chances of using FIVE 2.65 shims at the same time are exactly ZERO. Your bike only has four shims.

You really need to do your bike and yourself a favor. Check your clearances again, but also remove your other shims ONE AT A TIME and record their sizes. That way, when you get around to checking clearances again, you can have the proper shims ready. Clearances only get tighter, you will need the next thinner shim.

If your clearances now are on the looser side of specification, you might not need to change a shim next time, but if they are approacching the minimum spec, you will want the next shim ready.
If you are interested in having a handy place to record your clearances and shim sizes, take advantage of the offer in my signature.

.

I used the zip tie method today to check my 4 valves. It is easy after one gets the routine down. Cylinder 1 had a 2.75 shim on the INtake with no measurable clearance. I ordered a 2.65 mm for that. The exhaust had a 2.54 mm shim and .04 mm clearance.

Cylinder #2 had a shim marked at 2.68 mm for the INtake with .05 mm clearance. The exhaust also had a 2.54 mm shim with .06 mm clearance. My surplus of 2.65 mm shims will help me on the intakes for a while .... but NOW I know what shims I really need for the next valve check. As usual, thanks for the good advice.

 

[Steve]

Just wondering where you found 2.54 and 2.68 shims. :-k

They are marked in increments of .05mm, but some have an "X" at the end.

.

 

[dennco2]

Just wondering where you found 2.54 and 2.68 shims. :-k

They are marked in increments of .05mm, but some have an "X" at the end.

.

Those odd size shims were actually marked on the surface ... but not the OFFICIAL looking markings. The other EX shim had no size marking but I carefully measured 2.54 mm with my Calipers. They were all in there ... when I bought the bike a year ago.

 

[Steve]

Your "carefully measured" 2.54 shim was likely a 2.55. Since they are hardened, it's not very likely that it has worn down to 2.54, it's more likely that your calipers were not quite zeroed or just slightly off and the shim is on the thinner side of the production tolerance. Regardless, treat it as a 2.55 shim in the future.

The 2.68 shim is likely a 2.65x, which should actually measure 2.675. Rounded off, some calipers would read that as 2.68. Treat that one as a 2.65x in the future.

.

 

[chuck hahn]

Ive measured MANY a shim thats been in an engine Steve...and double and triple checked the calipers were zerod..and they do indeed wear measurably.

 

[dennco2]

My replacement valve shims arrived today .... so I was anxious to install the one I needed. Again, I used the zip tie method to hold open the valve ... but forgot to release the tie to get a correct clearance measurement. Was shocked when I got something like .051" clearance on the #1 intake valve. Going from 2.75 mm to 2.65mm shim gave me unacceptable .10 mm clearance ... so I swapped out the other 2.68mm intake shim and both intake clearances came in at .06 and .08mm. Success!

On the test ride after, I noticed a smoother idle and smooth performance though all the rpm range to 7,000. I also twisted the mixture screws slightly based on the color of the plugs. Very encouraging.

 

[Steve]

Actually, many of us will go out to 0.10mm clearance with no problems. Idle is a little smoother, makes just a bit more power in the mid-range, but might lose a tenth of a horsepower at the top. Also extends the interval to your next shim change.

Your clearances look good, though. :encouragement:

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