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78 R100S fork clunk  

ray wilson
Trusted Member Expired Membership

I've had this bike for about 3yrs, it had sat for a couple years tarped.  After refreshing all the vital fluids as required on a new purchase, I discovered while changing fork oil that one side was frozen and it wouldn't flush out. I don't remember all that I did but eventually I got both forks flushed and moving as they should. Cleaned and tightened the head bearings as to Wobbly's excellent advise. When I have it on the center stand (fixing that is my next challenge) I can pull up on the forks and there's no head bearing slop. But when it's on the ground, I can pull up on the bars or go over a bump a little too fast and it clunks pretty good. I'm assuming I need to disassemble the forks again and probably renew the inner workings. It sounds like my coils are not tight in the fork tubes (that sounds like a personal problem). Any advise on this? 

Ray Wilson



Topic starter Posted : 10/03/2020 10:37
Richard Whatley
Member Moderator

Ray -

Sorry to hear of your noise issues. I'm not aware of any "Airhead fork concerns" but we can review some common fork problems and thoughts. Maybe one of them will stir your creative juices...

• How many miles ago was this work completed? Maybe it's simply time to change the fork oil again. Especially if there was water the last time, or you've been pressure washing the bike since the repair. And what weight fork oil did you use at that time ?

• Consider that when you sit on the bike, it is natural to assume that any noise from the front is the forks. That may not be the case. I had a R100 that made a loud "Clack !" anytime the forks compressed under 3mph. Turned out to be some worn EDC brake rotors. So it could just as easily be wheel bearings, caliper mounts, front fender or even rotors. Check around. Have a friend stand to the side and help you listen.

• I've been informed that a lot of the Airhead fork internal parts are no longer available for some models. Before you start disassembling, you might consider checking parts availability first. Just a word to the wise.

Hope this helps.

[color=blue]Don't hide 'em, Ride 'em !!

Posted : 10/03/2020 13:18
ray wilson
Trusted Member Expired Membership

I have about 2500mi on it since i worked on the forks. I have a newer GS as my primary distance bike. No pressure washing. Kept in a garage so it's dry. I'll do a fluid change. It just sounds like there's a spacer missing although there's plenty of tension on the large fork cap when i open the top of the forks. 


Topic starter Posted : 10/03/2020 13:33


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