Vibration - my 89 did it as I was succumbing to goats.
If anyone remembers the s****th strain involved the starter clutch dying, the clunking at start creating vibration to get the magnet delaminated and the fragmenting magnet shredded the alternator.
If I remember Goat also had increased vibration as his was dying.
The Starwalt strain is almost the opposite of the srinath strain, a fragment comes loose form the rotor gets lodged into the starter clutch, locks it in the on position, and the motor then takes the starter for a 100,000 rpm ride, fragmenting the starter and everything inside it.
Good times ... 
Cool.
Buddha.

Thanks for the encouraging words.... 

Goat's, starwalt's and sr***th's can all be tested by opening the left case.
Cool.
Buddha.

IM guessing I should do a search for that stuff.

I really didnt want to get that messy this weekend. Oh well 

Its messy only when it starts to get fun 
Seriously, if its not goats or any of its variants, you will be able to get the thing back together with barely a spoon (hope you have very very very large spoons) of oil spilt.
For less oil spilling, put the bike on its right side onto some old car tires ... Then just take of gear shift, the sproket cover and then the alternator cover. If you tear the gasket, have a case of beer ready, you can cut the gasket out of its carton. If not, you can drink the beer.
Cool.
Buddha.

oh yeah! Mine had the shady vibration from the left side, i ignored it for a long time because at high rpm's it was okay. Finally one day, i realized it was goat's.  and ended up with 1 month riding down time. It just takes one hour of your time - drain the oil and then open to left side crank case but it will save you a significant amount of money the sooner you diagnose it. 

Is there a writeup on what these symptoms actually look like or something more in detail? I cant seem to find anything but references to them with a  search. (ie "goats")

You know, when I was looking online at a GS500 valve clearance chart, it says if you are measuring .03mm its too tight (Which is the low end of what the clymer manual states) and should switch out.

All my valves were .03... except for one, which was a tad looser. This gonna cause me some issues?

And where does one get a fancy group of shims for under a few hundred dollars? I can grab a tool and already have a micrometer and feelers.

(This wouldnt be the first time valve adjustment in a Clymer manual have been wrong... grr..  )

Quote from: Azzy on July 22, 2008, 12:39:38 PM
You know, when I was looking online at a GS500 valve clearance chart, it says if you are measuring .03mm its too tight (Which is the low end of what the clymer manual states) and should switch out.

All my valves were .03... except for one, which was a tad looser. This gonna cause me some issues?

And where does one get a fancy group of shims for under a few hundred dollars? I can grab a tool and already have a micrometer and feelers.

(This wouldnt be the first time valve adjustment in a Clymer manual have been wrong... grr..  )

The Suzuki specs says valve clearances of 0.03 mm - 0.08 mm are fine. If your clearances are at 0.03 mm, you should be ok to leave the shims as is.

If you want to go ahead and change shims, the wiki should give some helpful info on checking valve clearances and replacing shims ($5 each):
http://cgi.stanford.edu/~sanjayd/gs500/Maintenance/CheckValves
http://www.bbburma.net/Documents/ValveAdjustmentVideo/GS500_Valve_Shim_Selection_Chart.pdf

Looks like all but one are .03, the smallest blade I have is .o3mm, so, I would say its out of spec.

Guess its time to buy a tool and some shims.

also remove one of teh grips, and fill teh bars with BB's ( this DOES WORK btw )

Quote from: Azzy on July 22, 2008, 07:40:30 PM
Looks like all but one are .03, the smallest blade I have is .o3mm, so, I would say its out of spec.

Guess its time to buy a tool and some shims.

I'm confused  You said the clearances are 0.03 mm, but then said the shims need to be changed. Did you mean the 0.03 mm blade will not fit (i.e. the clearance is less than 0.03 mm)? In that case, I agree that the shims need to be changed.

Quote from: yamahonkawazuki on July 22, 2008, 08:16:55 PM
also remove one of teh grips, and fill teh bars with BB's ( this DOES WORK btw )

Tried that... not much of a change.

QuoteI'm confused  icon_confused You said the clearances are 0.03 mm, but then said the shims need to be changed. Did you mean the 0.03 mm blade will not fit (i.e. the clearance is less than 0.03 mm)? In that case, I agree that the shims need to be changed.

One of them is less than .03, as the .03 blade wont go in. the other will go in, but its a tight fit (on the .03)