| Effect of preload on fork seals
Hi all
The left hand fork seal (Ohlins!) has been leaking quite badly on my 888 for quite a while. Thinking this to be the cause of its relative instability on corners, I decided just to put up with it until I could find the time to have it fixed.
Anyway, having been well stuffed on a roundabout yesterday (again!) by a 750GSXR, I decided to see if things could be improved at all by twidling with the adjusters.
Now, fork preload is usually very easy to set, and so long as you can count the same number of rings around the adjusters, you can't go far wrong. However, those on my early Ohlins forks are different. There is no visible means to compare one with the other - except for the threads showing atop of the fork. Looking at mine - and the threads showing - they seemed to be adjusted equally, but all the same I decided to wind them both to full preload, and then count the turns as they were backed off. Sounds simple in theory, but in practice the adjuster nuts just keep tightening. Forever!
The only way I could tell that the springs were fully 'compressed' was by listening for a strange 'clicking' noise from within the fork. As soon as the nut 'clicked', I considered it to be full preload and stopped turning it. (pure guesswork really!) The shocking thig was that I found one nut could be turned only five times before 'clicking' and the other could be turned fifteen - even though the threads atop the fork were of equal length!
Anyway, I counted back from this 'click-datum' an equal number of turns for each fork, tightened the locknuts, and tried the bike along the road.
Well blow me..! The handling was transformed! I (and the bike's previous owner, no doubt) have been riding the bike around with uneven length fork legs! It really is cornering as if on rails now. And as an added bonus - and this is after covering 120 miles around the bumpy roads of the Dales today - the bl**dy seal is no longer leaking!! (I can only presume the uneaven preload was putting a 'twisting' load on the forks, and thus straining the seals).
So, those of you with early Ohlins FG9050 forks and leaking seals - before renewing them, you know what to do. CHECK YOUR PRELOAD!!
Steve  | 
30-May-2004, 18:34 
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