KTM fork oil

[Cliff Cook]

Hi Guys,

I have acquired an 81 KTM GS 250.  Have new fork seals.  Can anyone tell me a good weight and quantity of fork oil for this pup?? Anyone have a reference to an owners/ shop manual Thanks,  Cliff

[tofriedel]

Cliff,

It depends on which size forks you have installed.  My guess on the 250 GS model you have 35mm fork tubes.  If so, after you drain old oil, replace seals and re-assemble forks do the following.
1. Remove Fork cap and spring 2. Compress fork completely 3. Add approx. 280cc's of fork oil (9.5 oz's)to each fork leg.  The oil level should be approx. 6" below the top of the fork tube. Extend forks , insert springs and cap.  This is the way I set up most suspension units.  If you have the 38mm forks, the quantity is approx. 370cc's (12.5 oz's).  Depending on your style and MC activity, you can either add or subtract oil to meet your requirements.

As for fork oil, I use ATF fluid.  There are a number of fork oils avaiable in different weights, again it depends on your style and MC activity.  KTM recommended 10 weight.

Tony

[Cliff Cook]

Tony, Thank you very much.  The forks are 38mm.  I have used your exact procedure for 35 mm on my 76 250, but the 38's on the 81 250 were new to me.

I will procede with your 38mm suggestions and make any adjustmente if required.  Again, thanks for the reply.  Cliff

[wfopete]

Cliff,

I just "acquired" an 81 GS 250 also (38mm forks)!  I raced it a Combs last weekend and bought the weekend before. It had not been started in three years. I tore down the forks due to dead seals, cleaned some ungodly gunk out of them, reassembled with new seal and ATF (the universal fork fluid). I'm sure the springs were shot but I had to start somewhere.  So with forks collapsed and springs removed I added ATF 6" from the top of the tube and added about 1.5" preload spacers.

If you don't know, Combs is littered with softball rocks EVERYWHERE. Probably the rockest CC course on the schedule. Guess what? The forks felt very good!

I'm not saying this is ultimate setup, but you may want to use it as a starting point for your forks.

Pete Petrick
175 Jackpiner
Slow but Good