CLUNK!!!!!!!!!!

[Tel]

Hi chaps,
           I`ve developed a clunk (the bike not me [smiley=laughing.gif]) it seems to be coming from the swing arm pivot area. Ive flexed the cranks from either side so I dont think its the bottom bracket. It seems to be worse if I ride down hill, as if its happening on rebound of the shock(ODS girvin) I`ve checked the bolts on the pivot are tight, but not too tight. I can get the same noise by dropping the rear end or pushing it off a curb, it does`nt seem to happen if there`s weight on the bike (XPX)
 Any help would be brilliant.
Cheers, Tel. [smiley=beer.gif]  

[Simon]

I'd go for the ODS unit developing this clunk,

but I would double check the top ODS pivot bolt,
I found in the past this needed to be pretty damn tight,
if this isn't tight enough to clamp the top sleeve/bearing then the sleeve moves in the frame because if I remember correctly the bolt is M6 in a M8ish size sleeve.

Simon.
 

[Tel]

Thanks Simon, whats my next move? Can I get the shock serviced.(cheeper the better )
By the way I checked just before I posted this to see Just how quick you are, thought you might have posted your next one before I`ve typed the question [smiley=laughing.gif]
Cheers, Tel. [smiley=beer.gif]

[orange]

All 3 of my rear shocks clunk (2 X ODS, 1 X NR-2) and all are for the reason Simon gives with the same symptoms you have.

[Tel]

Thanks Orange, so is this nothing to much to worry about, or will I get oily nuts and a damp feeling in my shorts (not for the first time)? [smiley=diaper.gif] [smiley=disbelief.gif]
Would it be ok just to carry on riding like this or will I risk damaging anything else?
Cheers, Tel [smiley=beer.gif]

[shovelon]

Could be the ODS getting low on oil? If the seals are good, you might just add some oil. Never done it yet myself but it looks pretty straight forward.

Or better yet, have Mrs. Tel do it for ya! Hey, Hey, Mrs. Tel?

Terry

[orange]

Don't know if oil needs changing (no harm I guess - you can experiment with different weights while you are at it), but I can testify it's an easy job and believe me if I can do it anybody can! Hardest bit is pulling piston out.

[Colin]

Tel,
Check the M6 Bolt that goes from the strut into the end of the ODS, mine came loose on my XP-X and exhibited exactly the same "CLUNK" under the same conditions.

Obviously, check the other bolts on the rear end at the same time, I found once they had been undone for the first time and the threadlok is broken, then they will gradually undo over time.

It's also possible that it's the ODS unit "topping out" under no-load conditions, I've heard this a few times on mine but usually only when I've suddenly gone ballistic over a bump (or person lying on the trail) and my 14st has suddenly left the ODS with very little to do for a few microseconds until it crashes back down on it and then Oh Boy does it know what's hit it!

Incidentally, I've just been up the Physio's and had a "CREAK" seen to in my neck.............£30's not bad for an annual service!

Col.

[Simon]

May pay to change the ODS oil
(its a doddle to do) doubt you can cure this if its a top out clonk in the ODS unit,
but I suppose you could make up some kind of
top out bumper for the ODS unit once you have it apart,
also try some 15wt oil in the ODS unit if your still
running elastomers,won't cure the clunk but will
perform better,

don't forget to check the bolts first though.

Simon.

[Colin]

I don't believe that the "topping-out" clunk of the shock is a problem, Pro~Flex talk about it in the instructions for changing an ODS from MCU's to a spring, also they say the oil can "froth" because the springs respond quicker than the MCU's did.
It will apparantly be exacerbated by using a lighter oil as well.
I've noticed the "clunk" (and it's only a little clunk) ever since I changed mine to speedsprings about 7 years ago and the shocks still work fine.........and I still havn't got around to doing the oil change!

My bet's still on it being the strut bolt !

Col.

[Matno]

If you can reproduce a feeling of "give" when the bike is standing on the ground by pulling up and down on the saddle, it could be your shock bolt where it passes through the shock mounts. I've had that happen on ALL of my shock mount bolts. Best solution I've found is just wrapping the bolt in as much teflon tape as I could squeeze in there. Might work for you...