"Clunk" in front forks after overhaul

[redzap]

Upon changing the fork seals on my '83 R65 (22,000 miles), I decided to switch out the OEM springs and installed new Progressive springs.  On the test ride, there was a "clunk" coming from the forks encountered on the bigger bumps on the road.   I thought I had installed them correctly but I did not do anything regarding pre-load.  Before I tear it apart again, is there an issue with pre-load I should pay attention to or perhaps amount or viscosity of fork oil?  I used 7.5 wt. oil and put in the amount stated in the owner's manual.  Thanks for your help!

[Bob_Roller]

I installed Progressive springs in the forks of my '81 R65, and had to install a spacer made from PVC pipe, did you install this part ?

[redzap]

I did.  Then again, did I?  No, I did.  Really.   I think..........              All joking aside, I did follow the directions applying to this installation.  Having re-read the directions, I am confident of that.  I may play around with the amount and/or viscosity of oil if nothing else crops up but knowing me, I will probably take the forks apart and double-check....

[Bob_Roller]

Do you happen to remember the amount of oil that you put in ?

I think with the forks dis-assembled, 210-220 ml is a required amount.

The stated 190 ml in most manuals is for just changing the oil.

[airhead]

Are you sure the head bearings are properly adjusted? Even if you didn't remove them for the fork change, sometimes changes in one area can impact on another and show up deficiencies that otherwise weren't noticed. Easy enough to check.


Bill......................;-)

[nhmaf]

Can you tell if the sound is coming from the top/upper part of the fork tube, or somewhere down in the slider end ?(I realize that this is often not easy to tell)
When I replaced my OEM springs with progressive springs I had read that some folks found that putting the spacer at the top made things 'quieter'.(normal instructions say
to put the spacer on the bottom, which I did)   I don't know if this applies to your situation, but the claim was that spring shifting against the top plugs in the fork tube could cause noise, that  was much less apparent when the spacers were put on the top instead of the bottom.   I can't say whether this is true or not, but the spacers are
there to get the proper amount of spring preload for the shorter R65 forks.  Technically, it shouldn't matter if the spacer is at the bottom or at the top.   Something to consider if you end up running out of other things to try..

When you put in fresh fork oil, how did you determine the proper amount ?    I put in 210cc in each when I replaced my seals and springs.

[redzap]

I don't remember how much oil I put in.  It sounds like the first thing I should do is double-check that by changing it before I take the forks apart.  Right?

[nhmaf]

It is the quickest/easiest bit to do before resorting to larger disassembly, so if you don't know how much oil you used, I'd try it again.
I found that you might want to try it with 210cc first.  You;ll probably hear some noise for the first x compression strokes or first few miles
of riding, but it should ideally quiet down soon afterward if all is well.  If you still hear noise after this, maybe try adding another 10cc or so of
oil - don't go crazy and pour in alot - sometimes just raising the level very slightly is all it takes.   If that still doesn't work, then you can
start with taking things apart.

When you reassembled the forks and put the wheel on, did you leave the axle pinch bolts loose and compress/bounce the front end a couple times to
set the forks/axle sliders so they don't have stiction during their travel ?  There is a bit of a trick to it, if you haven't done this sort of thing before.

[redzap]

Thanks for all the feedback; I really appreciate it.  I'll try all of your suggestions and let you know how it goes.

[redzap]

Well, guys 'n gals, it's finally Friday and I got to work on the bike.  I took off the wheel, drained the fork oil and measured it.  It appeared I might not have put enough in first time.  I re-filled it with 210-220 cc's and reset the wheel  so it seated.  Took it for a ride on a cool Montana day (about 46 degrees), hit some rough spots and even rode over a manhole cover.  Lo and behold, no more "clunk."   I don't know if it was the amount of oil or reseating the wheel so the sliders wouldn't bind that fixed the problem but I am relieved nevertheless as I don't have to take the forks off and check the spacer.  Now onto valve adjustments and changing out the push rod tube gaskets.  Thanks for your help!!  

[Rob Valdez 79 R65]

I'm putting my money on low oil level.

Good to read about this stuff.  Thanks!

[Ed Miller]

I don't remember how much oil I put in.  It sounds like the first thing I should do is double-check that by changing it before I take the forks apart.  Right?

In an IDEAL world you would check it by referring to the work in your note book and seeing what you did.  Books are really nice to keep for maintenance.  Especially if you have the same bike for over 20 years.

Rob, does your book go all the way back to day one?  I would love to read one like that.  

[Rob Valdez 79 R65]

My world is FAR from ideal, I am afraid...  

[thrang]

I had the same thing when I replaced the RT's stock springs with progressives. The cause was the PVC spacer compressing slightly and after a little fiddling I cured it with 1mil shim under the top plugs and a playing around with the oil levels. (210cc's after the rebuild, and 185 on a change and they have been fine since.)

[nhmaf]

I love it when it's the simple things that work out fixing the problem !