I pulled the front sprocket cover off today to find that it was loose, almost to the point of spinning on the shaft.  pulled it off and the shaft is ate up with almost a grove in it.  how hard is this to fix???  thanks

Wow.  This is the GS500 owner's worst maintenance nightmare.  If you ride your bike to the dealership and tell them to fix it, it's going to cost about what the bike is worth.  Better if you can do some or all of the work yourself.  You need a new splined shaft and the engine cases will have to be split to install.  First, the engine will need to be removed from the bike.  You can stop there and haul the engine to a shop and save a good chunk of change, or you can proceed on your own.  Never tried it myself, but there's a chance you can turn the engine upside down, remove the case bolts, split the cases, and make the repair without disturbing the rest of the engine.  

Or, maybe it's time to sell.

You CAN split the cases without removing the cylinder and head
The only bolt for the cases on the top is under the starter cover plate.
Once that is removed, you can place the motor bottom up and take out the rest.
You do need to remove the side cases and the clutch hub assembly.
You can use a metal clutch plate and a pair of vise grips to make a tool to hold the assembly from moving. Clamp the vise grip on the edge of the plate.
Slide the plate in the clutch hub with the pliers in a slot on the outer hub.
You can wedge a penny in the gear at the crank. This will keep the assembly from turning when you loosen or tighten it. You'll need an impact driver for the 3 screws behind the clutch hub assembly and the oil pump screen. That's all you need as far as special tools go (oh a torque wrench too). :mrgreen:

You can pick up a complete tranny off Ebay. Just drop it in. I'll help walk you through it if you want.

So is the spline post a part of the transmission?  Can i get just that part or would it be easier to just get the whole thing?  Also, is there a temporary fix for this problems, like wedging a couple of small nails in between the sprocket and splin.  Thanks for the info.  Not what I was wanting to hear  

yes the "splined shaft" is the output shaft of the tranny.

Yup, I can relate to that one, this was mine
http://bikersgrove.clickhere2.net/cgi-bin/i/19.jpg

and this is what it looks like inside

http://bikersgrove.clickhere2.net/cgi-bin/i/31.jpg

best get yourself a manual, if you have never done it before, its fairly easy to do, just remember the hidden bolt under the starter motor

Quote from: Bob BroussardYou CAN split the cases without removing the cylinder and head

Ah, that's good to know.  Otherwise, if it ain't broke, don't touch it!

How about tack welding it on for the time being???  Would that work?

A "tack" weld certainly isn't going to hold.  That shaft is *supposedly* hardened steel and if so it will become very brittle at the point of weld.  Brazing might hold awhile but it would fry the seal.  Sorry, I can't think of a good shadetree solution.

Quote from: knowlsey

and this is what it looks like inside

http://bikersgrove.clickhere2.net/cgi-bin/i/31.jpg

Good pic, "knowlsey."  This should be recommended viewing for all the forum "wheelie freaks."  This is the wrong bike for that purpose.

Quote from: SupernakedHow about tack welding it on for the time being???  Would that work?

If you used a mig welder, you could get a couple short welds on it.
I'm sure it's been done before. Just do small welds at a time so heat buildup is minimul. And let it cool down between each weld. That way the seal won't be damaged and any hardness of the shaft won't be lost. Although i'm not sure how hard the shaft is if it wears out before the sprocket splines do  :dunno:

UM, not sure what wheelies have to do with a worn out tranny shaft.  Hitting the gears hard on the track is just as damaging.  In fact, if you clutch up your wheelies all you are going to wear out is your clutch and possible your front fork seals.  Depends on how good you are.