Vintage KTM GS500 dirtbike any info?

[herman maire]

I tried posting this in the " Old's Cool" tread but no replies.

Does anybody know any details on this model bike? I came across this early 80's 4stroke KTM GS500, it needs to be restored as the timing belt broke so engine needs a rebuild . They are asking $600 but I was thinking of offering $400 but I cant find any engine part parts available. Does anybody know a parts source for engine parts?

Any thoughts? Its very possible its just not worth the headache. How would this compare to a CR500 honda ?

Any replies appreciated.


[IMG][/IMG]

[Navin]

Rotax powered, see Ron Wood for the lump parts.

It is a friggin tank. You can build it for big power but it will always be heavy and enormous. This bike made the LC-4s of the 1990s seem small and light!

Cool bike still, you don't see many/any anymore. Rare even back then.

[nevgriff64]

Lets move this over to Thumpers and see what they can add.

Orange Crush is for KTMs, but designed for 950/990 twins.

[what car??]

Buy it! If anything else you have a cool bit of history. I would buy it if I came across a cool bike like that one. Just my two pennies...

[BIG ED XT FAN]

I rode a enduro in florida and there was a guy on that bike. Did wheelies all day long!!!! Great power!!1 The front forks are from a yamaha yz model i think?? I think the forks were white power models. I buy it, you just do not see bikes like thay anymore!! Think it as art. BiG ED XT&TT 600 FAN!!

[MZRider]

Originally Posted by herman maire

I tried posting this in the " Old's Cool" tread but no replies.

Does anybody know any details on this model bike? I came across this early 80's 4stroke KTM GS500, it needs to be restored as the timing belt broke so engine needs a rebuild . They are asking $600 but I was thinking of offering $400 but I cant find any engine part parts available. Does anybody know a parts source for engine parts?

Any thoughts? Its very possible its just not worth the headache. How would this compare to a CR500 honda ?

Any replies appreciated.

Another one has surfaced!
Check out this discussion on ThumperTalk:
http://www.thumpertalk.com/topic/970...tax-need-info/

Here's the information I posted in case you can't access it there:

You're in luck - I searched the internet for a manual - any manual for years, and eventully managed to buy one. I can make a copy of my KTM factory original Owner's Repair Manual for you. May take me a week or so as my copier is broken and I'll need to go to the local Staples. If you need it quicker, I may be able to scan a few pertinent pages and send them to you. I will need your email address to do that of course, please email me at c.d.mullendore@att.net.

Here an interesting article about the KTM 504: http://www.cifumotor...3ktm/index.html

The Rotax engine in the KTM 504 is pretty well supported as it was used in lots of different bikes. For starters, I'd check with Keith at American DirtBike: http://www.americandirtbike.com/ and Ron Woods Racing: http://www.rotax.net/ .

If your bike has the original Bing carburetor on it, parts are available here: http://www.bingcarburetor.com/ .

Chassis parts are a bit harder to source, Andre Horvath's KTM Klassiker: http://tinyurl.com/86yrtxq is probably your best bet there. Some parts are off the shelf items (example: the front brake system shares parts with numerous small Italian bikes of the era). I do have most of a rolling chassis stashed in my attic from when I was attempting to build one from parts.

If you want a CD copy of the manual, I'll burn one for you.

Front forks are made by Marzocchi, rear shocks is a Fox Twin Clicker, front brakes are Brembo. DC Plastics sells some replacement bodywork.

I'd grab that in a heartbeat for $600. If you decide not to buy it, let us know. Someone here would like to I'm sure!

[mmurry]

rotax motor parts are still available but VERY expensive... and it is usually best to have a guy familiar with them do the work....

[rz35027]

Real cool old bike! And it looks to be in really good shape (except for the motor?)

Think of an old XR500 Honda, only alot better. It's a fast tank = does not compare to a CR500...

[WIBO]

CCM had that engine in them......find a source of parts on line by entering CCM 604

http://www.hainesmc.co.uk/ccm_motorc...cm_604_spares/

Engine diagrams here....

http://www.hainesmc.co.uk/ccm_motorc...engine_spares/


As with the other comments,rare as hens teeth...buy it for all the money it is...(restore it and post the restoration for us all to see ....)


:)

.

[herman maire]

Thanks for all the replys, you all pretty much gave me the motivation to go and buy it. I decided to just take a gamble on it even though Ron Woods suggested I only buy it if I take the cylinder head off and inspect for damage. The owner was not very negotiable on the price surprisingly.

I went to pick it up at 9pm, got the bike back home and in the garage by 10pm and was already dismantling the bike.
What I started with

A few hours later

For some reason it was like I was a possessed maniac , I could not stop wrenching until it fully dismantled

[herman maire]

I did receive 2 new timing belts with the bike purchase, they were purchased at a Harley Davidson dealer for a bike that used the same Rotax engine . Its the original DAYCO brand .


Once I got the engine out, I could not help but have a look inside the valve covers, everything looked really good, to me anyway

[WIBO]

Congratulations on your purchase....

You've bought a piece of rare moto history....

Keep the pics coming or start a new thread?

Good luck with the moto

[MZRider]

My offer of a free manual on CD stands.

[Kawidad]

[Kai Ju]

Originally Posted by herman maire

Once I got the engine out, I could not help but have a look inside the valve covers, everything looked really good, to me anyway

The right side, as viewed, valve cover bolt hole appears to be cracked and stripped, maybe get it welded and recut the threads.
Also, if the valves are bent you should have a very large amount of clearance at TDC compression. If they are in spec, or at least close, you should be ok. Do a leak down test to verify.
I had one of these engines in a 250 Ninja and used to ride the crap out of it for about 20,000 street miles.

Have fun with that one.