Stiction and Front Forks

I've tried everything to eliminate the stiction from my front forks. I've checked allignment, oil level and the pre-load of the springs. What's happening is they freeze up during small bumbs and transmit a shudder until larger bumps are encountered. This is driving me nuts! Anyone else experience this with their KZ 650?
This is a 1981 KZ 650 CSR with original fork springs.

Raymond
Augusta, Georgia
1981 KZ 650 CSR

Have you had the forks totally apart yet? That might show you something going on inside...
You have one tube sliding inside another. The only way I can see one sticking is if a tube is bent, or the insides are gummed up. Hopefully all they need is a good cleaning.

ditto,im going with gummed up.

I don't know id it will help any, but here is a LINK to a thread in the archives where I posted some info on how to remove stiction from the forks.
That's weird, I remembered posting that a year ago, but don't ask me what I was doing last Tuesday :laugh:
Technical info sticks in my mind forever, everything else just slides on through

Post edited by: steell, at: 2006/04/08 21:56

I have had them totally apart, found it a little gummed up, but in other wise good condition; clean everything up and re-assembled them. After putting it all together, and even doing the gpz shake-down, the forks still stick on the slight bumps.

The triple tree yokes appear to be fine (unbent), I'm using 15W fork oil as per the manual. I just can't figure this out.

I have a 1980 KZ650 with the shorter forks and have no problems with it. Is there an inherant problem with the 81 CSR leading front axle forks?

Thanks for everyone's input!

Try dumping the fluid again and check the color .
It should drain clean .
How was the length of the springs???

If it's not the fluid then I think one or both tubes are a bit bent. Unfortunately you may need to take them apart again to measure them, and see if they are straight.

If your forks arent bent I would try this:
1) when mounting your front wheel, leave the front wheel clamps slightly loose, take the bike off the center stand and push down on the forks a few times. This should center the wheel on the forks. Then tighten up the clamps (while an assistant is holding the bike upright).
2)-more work- pull the fork springs, loosesn the axle and axle clamps. Push the front wheel and lower fork sliders up to the top of the travel. Tighten up the axle and clamps. With out the springs, you would/ could be able to feel the stiction when pushing the wheel through its travel.
Through mass production, the machined parts have variences. A small varience in the axle width may cause the stiction that you are experiencing.
The 3rd method would be to do #2 again, but this time loosen up the fork clamps and then tighten up the fork clamps first, then the axle and axle clamps.
Fish

The Fish wrote:

Through mass production, the machined parts have variences. A small varience in the axle width may cause the stiction that you are experiencing.
Fish

Good idea The Fish. If the forks are being spread apart wider than they are designed, they would bind up.
Could there be any spacers or bushings on this model that could be installed wrong, leading to this sticking?

I would also check to see that the forks are straight. Any small imperfection will cause sticktion. Also check your triple clamps to make sure they are true.

Take the fork spings out and move the lower end up and down by hand to see where it's binding.

Thanks for all the feedback on this issue. I really appreciate it.

I finally got around to trying the above suggestions and here's what I found:

1) took the springs out and worked the forks up and down and felt where they were sticking, which was near the top (fully compressed). I loosed the axle and the top of the steering head as well as the fender connections until the front tire would come back down on its own weight - no stiction.

2) I tightened everyting back up (no stiction), then put the springs back in and got the same stiction as before, although now I'm noticing a lot of strange noises coming from inside the tubes - a squeaky kind of worn out spring kind of squeaking.

The springs are the original ones. I measure them while out and found they measured around 16", which is short of what my manual calls for. I'm thinking I should probably replace them before I go much further, although I'm reluctant to drop more dime on this thing if it doesn't work in the long run.

If I get new springs, what's the best way to go? OEM? Progressive? I usually get this sort of thing from denniskirk.com - is there a better place to go?

Any toughts out there?

Thanks again for the help!