1991 R10OGS front fork oil weight

Gelandestrasse

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I'm due a change of oil - wondered what the consensus might be on left/right fork oil grades and quantities that people are using? It's for road use if that makes any difference.
 
Looked and found this:

Left : 75% 15wt, 25% 20wt

Right : 100% 15wt

Also found: 410cc in the left and 440cc in the right, 32 psi front 36 psi rear

I'll give it a go! (Thanks, barny)
 
Ah that brings back memories of mixing my fork oil concoctions for my old GS. Happy days.
 
Something I need to do soon. Bookmarked.


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I took a 'strategy path' and filled right hand side with 15W, left with 10W. The oil I took out was in not bad condition (RHS murkier than the clear LHS). If I am not happy, I'll drain LHS and fill with 15W. Then, If I'm not happy, I'll drain a bit off the RHS and top-up with 20W.

So far, only about 10 miles on/off road done, but it feels better at the front. Obvs I'll do a few more miles. I just wanted the front wheel to stay on the ground whilst pushing on a bit.....
 
The "Millichamp" formula works fine on the road definitely a lot smoother than standard. I also changed the springs to Motobin progressive once I had tried the oil formula on the original springs, which had to be better than 25 year old standard spring and they also were a good step.
 
Something off a thread I started on adventure rider about rear shocks.
This guy swears by this front end set up. I thought it may be of interest.

For the front fork, just replace the oil and put in ATF (Dexron III) for the rebound leg (right side). ATF equals 7.5 wt fork oil but is much better specified and cheaper. Put 2.5 wt fork oil (Fuchs silkolene or Ravenol *) in the left fork leg. The oil in both legs should be on the same level. If you strive for a little more progression, raise the oil level in each leg up to 40 mm (which is roughly 40 ml each). This setting has been elaborated over 27 years and almost 200k km.
 
That is a good point about oil levels, by increasing the air gap/ reducing the oil level will soften the suspension and increasing the level will make it harder due to locking up. Although a different BMW my Urban GS needed a much larger air gap to improve the ride due to hydraulic locking on large bumps. I do have an R100gs also, so I have do experience of both.
 
That is a good point about oil levels, by increasing the air gap/ reducing the oil level will soften the suspension and increasing the level will make it harder due to locking up. Although a different BMW my Urban GS needed a much larger air gap to improve the ride due to hydraulic locking on large bumps. I do have an R100gs also, so I have do experience of both.

That's true but it will also depend on correct spring rate and preload which determines how high in the stroke the fork is :)
 


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