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Damping Rod Install

gatorforge

CB750 Enthusiast
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Fredericksburg, VA
So while I'm gathering funds to do more work to the motor, I'm working on rebuilding my front suspension. I got it apart no problem, and got in springs and emulators from race tech and new seals from all-balls. I'm reassembling the forks now, and the first one went together like a dream. The second fork is having a bit of an issue with the dampening rod. When I screw in the allen bolt from the bottom, the dampening rod spins rather than allowing the screw to continue to thread in. I can get it 80% in, but the rod will spin and not allow the bolt to tighten all the way down. I have cleaned the threads with a brush and pick, and lubed the threads very lightly. Out of the fork, it screws in easily, but without being able to hold it, I can't tighten it down in the fork. Any advice would be appreciated.

Thanks,
Lance
 
As this is the SOHC forum I assume your talking about the bottom pipe? (#8 in the photo) It looks like the spring rests on the top of the bottom pipe.

Put the spring in and cap on, turn it upside down and push down on it to apply spring pressure to the other end of pipe?

Capture.JPG
 
@Dave Thats correct, screw (#19) through the fork slider into #8. Just assembled, and with spring pressure, it pulls the screw up tight, but the rod is still spinning even under spring pressure. Once pressure is remove, the screw again has a few mm of in out play.

Thanks,
Lance
 
So I tried that technique again and got the screw a little tighter and thought it would be ok. Its not.

Any other ideas on how to get it tightened down?

Thanks,
Lance
 
Gotta have that bolt able to thread into hole 100% of the way with no friction at all. If spring in place and damper still breaking loose then the hole is tight.

I have done something wonky before like a proper OD sized split type lock washer on top of damper and a VERY slight notch filed in top of damper (depends on how close the ring groove is to top of damper) to help the lock washer end locate at spin, then spring on top and the lock washer then tries to hold damper from turning. It worked, then remove the spring and lock washer.
 
Thanks Guys! I'll give that a go when I tear it back down tomorrow. I'm not sure I have the correct tap here, but I likely do at work. I tried cleaning it out with a brush and pick, but that may not have gotten all of it.
 
Tap or/and die, brush won't cut it.

Dab a slight bit of antiseize on the bolt too to help it slip in. If you seal with like gasket or copper washer under bolt head then something carefully done like a sharp chisel and BARELY make a cut mark VERY LIGHTLY in the bottom flat register of the damping rod to raise a couple of highs on the sides of the cut on the end, then it will try to dig in to lock and not turn in the softer aluminum of the stanchion. Obviously, going overboard there will burn your butt.
 
So chased the threads and raised a burr, unfortunately the rod is still spinning. Any more ideas? A bit of plumbers tape on the nipple of the damping rod to tighten it up maybe?
 
If talking teflon tape it lubes parts going in it. And any fragging of it will give you utter fits when the strings of it clog your fork orifices. That stuff does not belong in a fork.
 
Have your springs been shortened???

Take the spring out and shove a broomstick in there long enough to torque your bolt down, or try using an impact. Just be sure you aren't cross threading


 
Good point.................put some more preload on the spring temporarily. PVC plumbing pipe of correct size sometimes will work too. Add an inch or two.
 
@amc49, I know teflon tape is a bad idea, just running low on options. The springs are shorter than stock, they're the race tech springs for that model. I have a preload piece of pvc, but I could try running the preload pvc piece with the stock spring, that would bump pressure way up.

@medyo, I have not tried a broomstick but I will give that a shot. I'll try anything at this point.

As always thanks guys.
 
Welp tried that too, can't get enough force down on it to get the cap on with a spacer and the damper won't tighten by any of the other above means so I think this one is going in the scrap heap. Shame it was tight when I tore it down but now it just doesn't seem to want to work.
 
Shorten the spacer, all you need is long enough to load spring more and still be able to get top cap started.

No magic there, patience and it goes in or the part has messed up threads, the two choices there.
 
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So after quite a bit of headache I got the fork finished. Aaaaand it was my fault. At some point the oil seal the dampening rod seats into had com out and was sitting on the workbench next to the forks. Once I reinstalled it, the damping rod tightened right down and everything fits perfectly. Forks are now filled with oil and installed. Thanks for all of the help.
 
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