Help determine what shims I will need.....

[utgunslinger13]

While pulling (more like attempting) the head off the bike today, I also measured the valve clearances and they are WAY OFF.

Problem is, my feeler gauges have 2 sets of numbers (standard and metric I'm assuming) but I don't know which is which so I'll provide both.

For the left exhaust valve there was a 2.70 shim in, and the clearance was either .005 or .127
For the right exhaust valve there was a 2.80 shim in, and the clearance was less that my smallest feeler gauge that is either .0015 or .038
For the left intake valve there was a 2.65 shim in, and the clearance was less that my smallest feeler gauge that is either .0015 or .038
For the right intake valve there was a 2.65 shim in, and the clearance was either .002 or .051

Thanks,

Nick

[Paulcet]

Your first number is inch, the second is mm.

If your buckets will still turn, I would suggest you go down one size on the right ex and left in.  And I'd suggest you go up one size on the left ex.  Leave the right intake alone, it's on the money.

But before buying any, maybe swap right and left exhaust.  They might be closer than you think.

[utgunslinger13]

So would I be swaping these just to remeasure or to see if they will be within clearance?

[Paulcet]

I would remeasure. 

[utgunslinger13]

ok, I'll get to this once I figure out how to pull the head and cylinders without dropping the engine.  See my other post tonight for details.  Once I get them pulled and fix the leak between the case and the cylinders I'll get it bolted back together, move the shims and retest.

I know its been asked before, but what are my options as far as replacement shims?  Dealership, shim kits, etc?

[tt_four]

I just found this online on friday and it's amazing, I don't know how I never saw it before. It's all math you can do in your head, but the chart just makes things easier, plus helps you from having to double guess your placing of the decimal point.

http://www.bbburma.net/Documents/ValveAdjustmentVideo/GS500_Valve_Shim_Selection_Chart.pdf

[utgunslinger13]

Thats a nice chart, but I think I was confusing myself trying to figure out which measurement was standard vs metric.  Then I was thinking clearance was supposed to be 0.3-0.8 instead of 0.03-0.08!  Once I got my head straightened out, it all made sense!

Thanks!

[burning1]

For the left exhaust valve there was a 2.70 shim in, and the clearance was either .005 or .127 <-- Out of spec. Gap too wide. Install a 2.75 mm shim.
For the right exhaust valve there was a 2.80 shim in, and the clearance was less that my smallest feeler gauge that is either .0015 or .038 <-- Out of spec. Install a 2.75 mm shim.
For the left intake valve there was a 2.65 shim in, and the clearance was less that my smallest feeler gauge that is either .0015 or .038 <-- Out of spec. Install a 2.6mm shim.
For the right intake valve there was a 2.65 shim in, and the clearance was either .002 or .051 <-- In spec. Leave be.

I'm a little surprised that you are measuring too wide a gap on the left exhaust shim. To me, that would indicate either that your measurements are suspect, your cam cap isn't tight, or someone performed an improper valve adjustment on your bike.

Too wide a gap will cause valve noise. It will tend to cause your cams to slap the valves more, and will slightly reduce valve lift, which can throw off your carb balance and cost you power.

Too tight a clearance will cost you compression, and may not permit your valves to seat against the head fully, preventing them from cooling off as well as they should. In extreme cases, too tight a clearance will result in burnt valves.

Nick, your GS500 takes 29.5 mm shims, which are available from Parts Unlimited. You can order them from pretty much any motorcycle dealership. I wouldn't expect them to be in stock; Unlike many other shim sizes, the 29.5mm shims are only used on the Suzuki GS series bikes.

Also... If you are planning to pull your cams, you might as well look into a shim under bucket design, utilizing a more common shim size. That should give you more adjustment options (some shims are available in .025mm incriments, rather than .05,) and will reduce valve float.

[burning1]

By the way... Since you can't measure the clearance on your right exhaust and left intake, it may make sense to also buy a second 2.60mm shim, and a 2.55mm shim, just in case the clearance is so close that you need to go down 2 sizes. The shims cost $10 a pop, and you'll need them eventually anyway.

[tt_four]

Then I was thinking clearance was supposed to be 0.3-0.8 instead of 0.03-0.08! 

I did that, twice I think. I kept going to stores and buying feeler gauges thinking they were plenty thin enough, then I'd get home and realize they weren't even close because I was thinking .3-.8. I got one eventually, but still the thinnest I could find anywhere was a .038 gauge.

[Allen]

Yeah, if you can turn the bucket with your finger then go down just one size, if you can't turn it easily then go down at least 2 sizes, I had to go down 4 sizes to get to spec on LT EX.  After you get all your clearances to spec, you may have to adjust the idle.

[Allen]

Swap the two exhausts and see if its close to spec, as long as the bucket can turn easily you have some clearance and the bike should run fine. Have fun.

[pandymai]

my feeler gauges go down to .03mm and i think i bought them off bikebandit.. not sure though. makes thing's nice cuz if that doesnt fit, then i know which way to go =P

[utgunslinger13]

I'm a little surprised that you are measuring too wide a gap on the left exhaust shim. To me, that would indicate either that your measurements are suspect, your cam cap isn't tight, or someone performed an improper valve adjustment on your bike.

Too wide a gap will cause valve noise. It will tend to cause your cams to slap the valves more, and will slightly reduce valve lift, which can throw off your carb balance and cost you power.

Too tight a clearance will cost you compression, and may not permit your valves to seat against the head fully, preventing them from cooling off as well as they should. In extreme cases, too tight a clearance will result in burnt valves.

Nick, your GS500 takes 29.5 mm shims, which are available from Parts Unlimited. You can order them from pretty much any motorcycle dealership. I wouldn't expect them to be in stock; Unlike many other shim sizes, the 29.5mm shims are only used on the Suzuki GS series bikes.

Also... If you are planning to pull your cams, you might as well look into a shim under bucket design, utilizing a more common shim size. That should give you more adjustment options (some shims are available in .025mm incriments, rather than .05,) and will reduce valve float.

To be honest, I would blame the original owner.  I bought the bike in June 2008 with a seized motor due to water getting inside the cylinders and rusting the pistons to the walls.  He also tried to install an electric tach and just shoved the tach cable into the opening on the back of the tach to hide the modification that was unsuccessful.  I've had to work out quite a few kinks from the PO with the wiring harness and eventually I just replaced it completely so I wouldn't put it past that he just shoved whatever shim he had in there.  I'm in the process of pulling the head and cylinders to replace the leaking base gasket, but once back together I'll be remeasuring gaps.

I have heard some noise from the top end, but this bike has only started 3-4 times since I've owned it, and I just took it for the first ride EVER 2 weekends ago.  I did notice some hesitation upon giving it throttle and the RPM's would dive before surging up and accelerating like normal.

Yeah, if you can turn the bucket with your finger then go down just one size, if you can't turn it easily then go down at least 2 sizes, I had to go down 4 sizes to get to spec on LT EX.  After you get all your clearances to spec, you may have to adjust the idle.

Unfortunately, I didn't check if I could turn the buckets before removing the cams but I will check this once I get the base gasket replaced and everything put back together.


I just checked the local Suzuki dealership and they do not swap shims, and if I get them my order by 5pm Tuesday they will be in on Friday.  Unfortunately, I'm supposed to be going to DC this weekend and won't be able to pick them up till the following week.

Thanks for all your help!

[burning1]

Did you check the torque on the cam caps before measuring clearance? It's possible one of the caps was loose, which would totally throw off your clearance readings.

[utgunslinger13]

I know the cam caps were tight because I disassembled the engine to replace the cylinders/pistons/rings and I know I torqued them to specs in the manual.

[jimjr]

I took the advise from the video and ordered the 2.15 shim and swapped it for the shims in my 2 tight exhaust valves and then measured the clearance. It makes you order an extra shim for $10 but now that you have it you never have to guess what shim to order again.