New to the Forum, Valve Shim question

[Pureformance]

So i just purchased my first street bike. Its a 81 GS650G with 10k on it. I paid hardly anything for it too.
The guy i bought it from told me it didnt start well when the motor was cold, but after it was warmed up it ran fine. (Which he then showed me before i bought it)
I found this forum and found the great resource of BikeCliff's page. I figured i would check the valves before i tried anything else to remedy the starting problem. Turns out i cant even fit a .001 feeler gauge on any valve. So i removed each shim and recorded each size. My question is, if my shim is say a 2.75, will going to the next size of 2.70 be adequate? Or should i go to something even smaller?
Also, i have a couple shims that have the X after the number, such as 2.65x. Now i saw that means its slightly thicker. So will going to say a 2.60 be ok or do i need to go smaller?

Thank you for your help!

[hampshirehog]

If you can't get your thinnest feeler gauge in there you can't work out what size shim will fit. The best thing to do is to find your thinnest shim and keep shuffling it around, measuring the gap each time, until you can work out what size shim is required for each valve. Then shuffle your remaining shims around to suit. If you're lucky you might only need to buy 2 or 3 shims.

Don't be tempted to turn the motor without a shim in place as you can damage the cam lobes. If you need to turn the cams, pop a suitable size coin in there as a shim replacement (just remember it's in there).

Most regulars will keep a very thin shim, say 2.20, as their 'checking shim'.

Oh, and welcome to the nuthouse.

[Pureformance]

Thanks for the tips! Back to the engine i go.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Pureformance,

You should always re-measure after fitting new shims to be sure you are still in spec. But until you get a good reading on the clearances and inventory what shims you have, it's tough to guess-timate what you will need. At this point a 2.20mm shim might be too thin. I'm sure you could use a 2.40 or 2.50 to figure what sizes you'll need to get the clearances in spec. I keep track of my clearances and what shims are in the bike. Then I can order a few shims ahead of time according to what I might need. I would also recommend getting a metric feeler gauge (not an SAE with metric equivalents) to make the math a little easier.

Anyway, let me share some GS lovin' too.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[tkent02]

A quick check, see if you can spin the shim bucket with your finger, with the cam lobe in the position specified for checking that valve. If you can, there is at least a tiny bit if clearance, something between zero and whatever you thinnest feeler gauge is. In this case one size smaller should be correct, should give a clearance of about .050 to .080mm or so.
If you can't spin it, there is no clearance at all, so zero or less, you can go two sizes smaller, the clearance should be .10mm or less, which is what most of us use for an upper limit.

If it takes more than two sizes smaller, I bet your valves are toast anyway.

[Steve]

Sounds like you have done all the work, let me offer you someplace to record it.

Read the last part of my sig.

.

[Pureformance]

Thanks for all the tips guys. I am able to rotate each shim bucket with no difficulty, so i hope the valves are going to be ok. I did unfortunately run out of time yesterday before work and wasnt able to finish up. But i got started using my smallest shim 2.60 to check the clearances (minus the clearance of where it originally was) And it looks like using that will give me the numbers i need.
Thanks to all again

[NoH2Oh]

If not already stated, Z1 is a great place to get new shims. Better $$ than OEM.