So I've found that the rear shock from a Katana as well as the rear wheel will bolt up with little to no modification. What other parts from other bikes will fit the GS500 without doing any real modification/fabrication?

Side note, I'm sorry if this has already been covered.

99 Yamaha R1 tail light.I got a steal of a deal on a Clear Alternatives tail light.Here's a pic
Also mid to late 90's GSXR600/750 bar ends work in the handle bars with the threaded inserts.89-97 Katana 600/750 swept spoke front wheels work.Also the 98+ front wheels work but they have straight spokes.They are direct swaps with no mods required.I'm sure you've seen the 4.5 98+ Katana and Bandit 600 rear wheel swap write ups.If I think of more I'll post them.

I did see that write-up. Side note, is there any difference in capacity between different year GS500 fuel tanks? Any upside to swapping out for another year's tank?

Check this out. http://gstwins.com/gsboard/index.php?topic=41960.0

The 01+ tank holds 5 gallons the older tank holds 3.5 gallons.The tanks are the same other than size.The bottoms are the same and the tank petcocks are interchangable.I have an 04 tank on my 89 using the 89 tank petcock.Pics are in the thread above.I plan to mod the seat to follow the tank lines like the 01+ seat.

cbr1000rr tailight also fits the gs 04+up pretty good

Quote from: erbilabuc on June 07, 2008, 05:45:03 PM
cbr1000rr tailight also fits the gs 04+up pretty good

Got pics.

There is atleast 300 bikes whose front end will bolt on to a GS ... right from a savage 650 and a kawi KX500 dirt ... (OK OK its just theoretical knowledge, those will turn it into a chopper, and I know cos I fit the KX one on a savage, and the GS uses similar sheite ) ...
F4 tail fits but doen't look that great.
A GR650 motor will fit in with minor mods.
A 36 or a 38 or a 40mm carb pack from a old school US GSXR 750 or canadian GSXR 750 for the 40's can be mangled  into the GS rack and fitted with GSXR mainfolds.
Buell headlight fairing fits with very little dremel tool work.
Someone also fit a Tri bar buell blast headlight If I recall.
Swingarms from various bikes, RGV's, GSXR's and what not.
Someone milled a honda hawk swingarm to fit also.
The list is almost endless dude.
Cool.
Buddha.

hey buddha give me more info on the bigger carbs and manifold what are the pros and cons and the performance gains

I have a rack of 36's I want to fit on the GR, I am yet to do anything with the thing though, so I dunno ... 
Cool.
Buddha.

Quote from: ben2go on June 07, 2008, 07:56:04 PM

Quote from: erbilabuc on June 07, 2008, 05:45:03 PM
cbr1000rr tailight also fits the gs 04+up pretty good

Got pics.

http://gstwins.com/gsboard/index.php?topic=39887.msg448200#msg448200

Quote from: The Buddha on June 07, 2008, 08:31:22 PM
I have a rack of 36's I want to fit on the GR, I am yet to do anything with the thing though, so I dunno ... 
Cool.
Buddha.

will they fit a gs? any gains

Yes I am sure they'd fit a GS cos the GR uses the same manifolds and has identical bore spacing ... I think it will give you top end and cost you low end.
Carburetion is about velocity ... in a way, fitting a 33mm carb to a GR may be actually smarter. However I  I have a bad pair of GS carbs one with a bad left carb (busted pilot fitting) and one with a bad right carb with a busted air mix screw fitting ... I plan to make 1 good one from these 2, then rack the bad ones with the 36's ...
Cool.
Buddha.

Quote from: The Buddha on June 07, 2008, 08:31:22 PM
I have a rack of 36's I want to fit on the GR, I am yet to do anything with the thing though, so I dunno ... 
Cool.
Buddha.

buddha, keep me informed on that. cause ive got a gr engine with carbs sitting in my workshop. engine has about 4500  on teh ODO. so i keep turning it ove  once every two weeks. to keep things moving.  BUT im curious. will a gs head bolt up to it, or must i use a gr head, and if i have to use a gr head, WTF do i do with teh exhaust exiting at an angle?

Yamahon ... fabbing up angled pipes is nothing ... If you want to, I'll sell you some when I get the thing close to done. Swapping heads is 10 times the work and your getting a worse head, smaller valves and almost the same volume when squished. Mine was cleaned up by decking and it works better than a GS head IMHO.
Cool.
buddha.

i ownder if there is a way to convert the gr to a six speed? ( IIRC its a 5?)

Quote from: The Buddha on June 07, 2008, 09:05:40 PM
Yamahon ... fabbing up angled pipes is nothing ... If you want to, I'll sell you some when I get the thing close to done. Swapping heads is 10 times the work and your getting a worse head, smaller valves and almost the same volume when squished. Mine was cleaned up by decking and it works better than a GS head IMHO.
Cool.
buddha.

But can it rev to 11000 rpm without valve float?GR red line is a round 8000 rpm.