What Size Shims?

[SB3]

I have a 78 Suzuki Gs550. I posted last night about taking the head apart and cleaning the valve heads and valves of carbon build up. I also replaced the valve seals. Anyways I can not get the lowest gauge on my feeler tool to go through any of the clearances (.0015"). What I collected from my post last night was that I just simply need smaller shims because my carbon is gone and my valves seal properly. Now my question is... what size shims should I order? Should I go down .05? or a whole .10 from my current sizes? My sizes are..


EX CAM 1=2.65 2=2.65 3=2.70 4=2.65

IN CAM 1= 2.75 2=2.80 3=2.75 4=2.75

 

[Nessism]

I'd swap the (EX) 2.65's in place of the (IN) 2.75's, and a (EX) 2.70 for the (IN) 2.80. Then measure the IN valves again. Obviously, you won't be able to measure the EX valves again because they will be tighter than ever.

Assuming you have good clearance on the IN valves, then plan to move the EX valves down two sizes. You may need to move a couple of the positions 3 sizes but it shouldn't take more than that.

EDIT: and just to be clear, never rotate the engine with a shim removed. The cams will be damaged.

 

[cowboyup3371]

Did you ever get Steve’s spreadsheet? It will help guide you; send an email to his account

 

[bwringer]

EDIT: and just to be clear, never rotate the engine with a shim removed. The cams will be damaged.

IIRC, you can drop a coin in there (a quarter is a very loose fit, or IIRC a Sacajawea dollar works) if you're swapping shims and need to rotate the engine without damaging the cams. OBVIOUSLY don't attempt to run it with spare change installed...

And yeah, the spreadsheet helps if you're confuzzled.

 

[Grimly]

IIRC, you can drop a coin in there (a quarter is a very loose fit, or IIRC a Sacajawea dollar works) if you're swapping shims and need to rotate the engine without damaging the cams. OBVIOUSLY don't attempt to run it with spare change installed...

.

For readers in the UK, a 2pence coin is a perfect fit.
I have a pill jar full of them for exactly this purpose.

 

[Wingsconsin]

I have a 78 Suzuki Gs550. I posted last night about taking the head apart and cleaning the valve heads and valves of carbon build up. I also replaced the valve seals. Anyways I can not get the lowest gauge on my feeler tool to go through any of the clearances (.0015"). What I collected from my post last night was that I just simply need smaller shims because my carbon is gone and my valves seal properly. Now my question is... what size shims should I order? Should I go down .05? or a whole .10 from my current sizes? My sizes are..


EX CAM 1=2.65 2=2.65 3=2.70 4=2.65

IN CAM 1= 2.75 2=2.80 3=2.75 4=2.75

Question to the hive mind ..
Are the 550 shims the same diameter as the 850s ?

IF the answer is YES -

I have a 2.60 , a 2.50 and a couple of 2.55 I could snail mail to you --

All mine are now at smaller sizes so a thicker shim is 'extra'

 

[Guest]

Question to the hive mind ..
Are the 550 shims the same diameter as the 850s ?

IF the answer is YES -

I have a 2.60 , a 2.50 and a couple of 2.55 I could snail mail to you --

All mine are now at smaller sizes so a thicker shim is 'extra'

I believe the 550's are also 29.5 shims?

 

[Steve]

All GSes that use shims use the same 29.5mm diameter shims.

.

 

[Beech35p]

I'm facing similar challenges. I have reduced the shims on 6 of 8 valves. My number 4 intake valve has me concerned. The factory installed a 2.7 shim on this 78 GS 750 but now, 55000 miles later, I'm down to a 2.4! I recently acquired this bike so this is the first time I've "run the overhead". If valve seat wear is the culprit for reducing shim thickness at what point does this indicate the need for head removal and valve work? It seems like going from 2.7 to 2.4 is a very wide swing. Steve, any ideas? You're spreadsheet is great!! Thanks for sharing this tool.

 

[johnod]

I just bought 1 of the thinnest shims , and measured from there, as I had the same problem.