I finally got my parts for the rejetting and since I had everything apart I figure check the valves too.  I have the Clymer manual and read the site put together for doing this so I am pretty sure I have it right.  The bike is cold and my smallest feeler gauge 0.0015" fits on cylinder 2 exhaust but the rest are too tight.  Should I try to remove the shims and replace them with smaller sizes?  How is it possible that the clearance, assuming the factory adjustment was correct, is tighter now?  How big of a problem is this?  Any help would be greatly appreciated since I have the bike in pieces all over the floor right now.
Thanks,
jake

If they are too tight, they are too tight.

replace'em.

Quote from: JakeI finally got my parts for the rejetting and since I had everything apart I figure check the valves too.  I have the Clymer manual and read the site put together for doing this so I am pretty sure I have it right.  The bike is cold and my smallest feeler gauge 0.0015" fits on cylinder 2 exhaust but the rest are too tight.  Should I try to remove the shims and replace them with smaller sizes?  How is it possible that the clearance, assuming the factory adjustment was correct, is tighter now?  How big of a problem is this?  Any help would be greatly appreciated since I have the bike in pieces all over the floor right now.

It can be a major problem (or get to be)... I have been having a lot of problems with my bike recently, and today I discovered that my valve clearance was almost .1mm off (which is two shim sizes).

If they are too small to measure, you can do two things.  The first option is to get a new shim 1 size smaller, and a lot fo times that will work.

If you want to be certain, though, call around and find a suzuki dealer who has a 2.15mm shim (or close to that, since what is in your bike is probably 2.6 or thereabouts) and measure the clearance with that in.  Use the chart in the Haynes manual (or search Kerry's posts, since he posted an image of it) to figure out from that what size shim you should get.

I had to drop 2 shim sizes on 2 of my valves, and 5 on one of them... 1 size on the fourth.  If you haven't noticed problems, you might be okay with just one size, but that is an option if you want to be sure.

Thanks goes to JohnLA, I believe, for the idea for that method.

I think you may be assuming that the valve clearance increases as things wear out.  Actually it's the opposite.  As the valve wears and seats further into the cylinder head, it reduces the valve clearance with the cams.  That's kind of the danger of not checking your valve clearance because if you start getting valve leaks they will start to burn as the hot gas goes past them constantly.  Also, they are not in contact with the cylinder head as often (or at all) which is what is supposed to them cool.  

Any body agree with this?  I'm no expert.

Rob

Thank you all,
Yes, I assumed the wrong way.  I figured clearance would be getting larger over time.
Okay, I have no gap between the valves and shims but I can rotate the buckets.  One size smaller should be okay then right?  The valves have never been adjusted so the stock shims are in now.  What size are they and what size should I buy to replace them.  My local shop said they have most sizes on hand and since I need to ride the bike to pick them up, I am trying to avoid taking it apart to measure the valves.
Thanks again,
jake

One last question:
Is it possible to replace the shims without removing the carbs.  I was not able to slide the cover off with the carbs on, but it seems like there is enough clearance to work underneath it?
Thanks,
jake

Yes, you can check the valves with the carbs on.  On top of the valve cover, is a small metal box about the size of an Altoids or sardine tin.  It has a breather hose from it to the airbox.  You need to remove that from the valve cover, before the cover will come out.  But no need to remove the carbs.

It seems a little fishy that 3 out of 4 valves are too tight; they usually don't wear that evenly among them.  Are you checking each valve with the lobe pointed straight up?  That's the "Srinath" way.  The pessemistic way to check, is to check the valve with its cam lobe pointed forwards, rearwards, AND up, and if any of the three measurements are too tight, then it needs adjustment.

All my valves on the 3 GS'es OK OK 2 Gses... didn't own the third for too many miles.... have all gotten loose... cam wear, shim wear, valve top wear all make it loose. Mine only get loose.
Cool.
Srinath.

With the valves properly gapped, and the rest of the modifications I had already made trying to fix the idle problem, the bike is running like a dream!  I ended up decreasing one shim by .05mm and the other by .1mm.  Also, I found it easiest to get the shims out by loosening the keepers on the cam and lifting it up 1/4" or so one side at a time.  One of the lobes was not consistent and had a different gap if it was angled slightly ahead or back so I took an average for the final shim.  One other thing that surprised me was each existing shim was different.  (2.72, 2.65, 2.60, 2.70)  I would have expected the stock shims to all be the same but I guess the manufacturing tolerances on each part in the system require create the variability.  

Anyway, I would certainly recommend checking the valves as a first step (not last step like me) for anyone else with idle problems.  It is not hard to do yourself, just remember to stuff a rag in the space between the cylinders so you don't end up trying to fish dropped parts out of the engine with a magnet like me.  (feeler gauges and jewler's screwdriver)

Thanks to all who gave advice and support,
jake

Congrats!  It feels good not to have to pay the shop all that money doesn't it?!?!?

I have to check my valve clearances too.  I checked 'em about 1 1/2 years ago so I am due.  (hey that rhymes)

Rob