K2 / Proflex Riders Group
General => Tech Forum => Topic started by: Connie on August 02, 2007, 05:54:04 am
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Hello! I recently purchased a Proflex 856 w/ Girvin ODS shocks. I spent about half a day cleaning it (think it was stored in a leaky shed for a bunch of years), put new tires on it, etc, and went for a ride. I had a great ride for about an hour, then started to hear a sharp metalic noise in the back when going over rough parts of the road I was on. The noise sounded sort of like a hammer tap, and I could feel it in the seat. I'm guessing that it is probably the rear shock? Is it possible to repair the shock on my own? Looks as though it would be easy to remove. Does anyone have a copy of the owners manual they would sell? Just a xerox would be fine. Am also looking for Girvin ODS shock info.
It was really amazing how well the bike cleaned up. I didn't pay much for it - it looked pretty rough - but after a lot of careful cleaning, the bike is a visual treat! Now, if I can just figure out the shock situation, or whatever is causing the noise. Any and all suggestions would be much appreciated.
Thanks!
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My daughter's name is Connie...
anyway, I digress! The noise could just be the point where the shock is bolted to the frame at the top of the unit. It's something we all seem to get to some degree. Try picking up the rear of the bike while stood beside it and drop the back end and see if it clunks then. It's just the bolt doesn't fit snugly through the 'eye' of the ODS. It's quite normal just ignore it.
If it's not that then I don't know. However, PM me your email address and I have some ODS documentation I can email you.
Also check out these guys. I bought their springs to replace the elastomers and they are very good. www.rapiddescentscotland.co.uk
cheers
Ed
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Hello Ed - Thanks for the info! I tried dropping the rear end while off the bike, and it still made the noise - though not every time. It would be great if it was just the bolt hole being a bit too big. My email address is ConnieandMichael@msn.com. Your ODS shock information would be very much appreciated!!
Is your daughter's name Connie or Constance? I'm a Connie, though both are fine names.
Thanks again - Connie
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Welcome Connie,
Two things I can recommend is check and see if there is a bottom out bumper on the shaft. If it is gone, it is bottoming out on the spring or cap.
Also check to see if there is still oil inside the shock. It may just be bottoming to fast and hard.
And like Ed said, check for lose bolts. Inside the frame, there are plastic bushings around the sleeve on the shock. Make sure the bolt is tight.
Again welcome,
Terry
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I've always had problems with the bolts being a bit "loose" in the shock bushing eyelets. Makes a little "clunk" usually most noticeable on rebound, but with every little hit. Solution has always been to just wrap the bolt with as much teflon tape as I could fit through the hole. Works like a charm, and costs next to nothing.
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I've always had problems with the bolts being a bit "loose" in the shock bushing eyelets. Makes a little "clunk" usually most noticeable on rebound, but with every little hit. Solution has always been to just wrap the bolt with as much teflon tape as I could fit through the hole. Works like a charm, and costs next to nothing.
Ah yes, I remember that situation coming quite often a while back. I remember the teflon tape comment too. That just may be the source of the clunk.
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Thanks to Shovelon and Matno for your helpful suggestions! -Connie
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Probably pretty obvious and may have already been covered, but not explicitly....?
Check the bolt from the strut into the end of the shock, if this is loose it will definately "clunk". Mine did this to me one day and I jumped to the conclusion that the ODS was knackered, remove the rear wheel and use an Allen key to check/tighten the bolt.
While you're at it, I would remove the whole shock, i.e top and bottom bolts, and check that all of the right bits are installed, i.e. split collet at bottom, spacer tube & 2 seal spacers at top.
See this diagram:
http://www.k2bike.com/tech_library/pdfs/97_spc657_strut.pdf
Then remove the MCU's (yellow squishy things) or coil spring if fitted and try to push the shiny silver shock shaft into the gold body, it should move in about 49mm (1.92") and be a bit of an effort to achieve this, it should then slowly return a fair bit on it's own.
If it neither opposes compression nor returns slowly with a damping effect then the oil has probably leaked out. and this could be the cause of the "clunking". see ODS service below.
If an ODS is used with a Coil spring then it may top out "clunk", I've occasionly experienced this on my Speedspring & ODS equipped XP-X(856), to no detriment.
see this article:
http://idriders.com/proflex/resources/ods_service.pdf
I'd expect any original MCU's to be Knackered by now, either rock hard or too soft and squashed into doughnuts, if this is the case then the limited travel could be causing the clunk.
check all of the above and let us know what you find.
The 856 is a great bike and I'm sure you can easily make it into an excellent ride!
Col.
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hi,
rds will have springs in shortly, they're being made at the factory at the moment. the springs will fit the ODS shocks on 856, 956 and so on.
cheers
callum
rds