1981 KZ550-D1 Forks

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31 Dec 2014 06:44 #657439 by Grobbies
1981 KZ550-D1 Forks was created by Grobbies
Hi to all from good ol' RSA.

Purchased a '81 GPZ a while ago in need of some rescuing. Stripping down has gone according to plan, and basically everything is removed and labelled (wiring loom took some time due to age) except for the motor, front forks, handle bars and the wheels. Only at this point have I noticed that the front forks seem a bit off. I can't see, or feel, any visible creases in the tubes and they also look pretty straight. From what I could see it looks as if the right tube is sitting slightly forward of the left, making the front wheel point to the left when the handlebars and fork frame is positioned at dead center. Basically what I am asking after this longish explanation, is whether the forks can be "re-aligned" without having to send the entire fork away for it to be done.

Thanks for reading, will try and post some pics on the whole process. I must,say my patience levels have increased ten fold over the past few days (swearing slightly as well).

I believe in percussive maintenance.

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31 Dec 2014 07:07 #657441 by Grumpy Ole Artist
Replied by Grumpy Ole Artist on topic 1981 KZ550-D1 Forks
Had the bike been wrecked? Check the steering stop (Small tab welded to frame under bottom triple tree) If it WAS wrecked, one side or the other of the stop will have a dent in it from being smacked by one of the tabs on the lower tree...I would go ahead & strip the forks down...(you are probably going to need new seals, progressive springs, cartridge fork emulators &c anyway) once apart, lay the inner fork tubes on something absolutely flat (glass table, &c) and give em a roll...you'll know if they are straight or not...if they prove straight, she may have been REALLY wrecked, & either the triples or the frame is tweaked...Hope this helps, good luck with her!

1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo

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31 Dec 2014 07:18 #657442 by TexasKZ
Replied by TexasKZ on topic 1981 KZ550-D1 Forks
It could also be that the triple clamps are not perfectly aligned. A relatively minor bump can do it. If that is the case, loosening allthe bolts and realigning the folks may be all you need.

On the other hand, the tubes may be bent. See GOA's post above.

1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
The following user(s) said Thank You: Grumpy Ole Artist

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31 Dec 2014 07:28 #657443 by Grobbies
Replied by Grobbies on topic 1981 KZ550-D1 Forks
Thanks for the info Grumpy and Texas. Will see what I can get done first before stripping the forks completely, if it pans out then good for me, if not...of to the shops I go. Will check the tabs when I get to the garage tomorrow Grumpy. But first, beers, they are waiting to caress me into the new year.

I believe in percussive maintenance.

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31 Dec 2014 09:12 #657457 by SWest
Replied by SWest on topic 1981 KZ550-D1 Forks
I got new for tubes at Z1 about $80. I would rotate my old ones until they were straight, sometimes leaked sometimes not. It doesn't take much.
Steve

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31 Dec 2014 12:26 #657473 by Grumpy Ole Artist
Replied by Grumpy Ole Artist on topic 1981 KZ550-D1 Forks
Thanx texas, I forgot about the clamps as possibility...I would plan on new fork seals & fork oil though!

1978 KZ650 B2
Former rides...1976 CB360T, 1985 Shadow 700, 1985 GPZ750Turbo

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31 Dec 2014 19:28 #657490 by loudhvx
Replied by loudhvx on topic 1981 KZ550-D1 Forks
Put the bike on the centerstand, loosen the fork clamps on one fork tube, then spin the tube. If it's straight, it will spin inside the clamps smoothly. If the fork is bent, it will bind and release during the rotation.

There is a bunch of 550 info in my signature, for that bike.

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01 Jan 2015 04:07 - 01 Jan 2015 04:09 #657502 by Grobbies
Replied by Grobbies on topic 1981 KZ550-D1 Forks
Thanks for the info loudhvx. Feedback will come from me in due time.

Hope every one had a great new year's day.

PS: Will get new fork seals and oil soon as well, thanks for the heads up Grumpy.

I believe in percussive maintenance.
Last edit: 01 Jan 2015 04:09 by Grobbies.

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01 Jan 2015 08:02 - 01 Jan 2015 08:03 #657510 by martin_csr
Replied by martin_csr on topic 1981 KZ550-D1 Forks
The front end of my 650 was akilter --- the upper triple was bent.
I checked it on a glass table by pressing down on a corner --- it rocked quite a bit.
The replacement only rocked a tad.

Also, check to see if the steering stop peg is bent.
Last edit: 01 Jan 2015 08:03 by martin_csr.

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01 Jan 2015 08:24 #657512 by Grobbies
Replied by Grobbies on topic 1981 KZ550-D1 Forks
So the worry about the steering stops indicating if the bike might have been wrecked before got the best of me. Got in the car and drove to the garage to check. Fortunately both stops were in "good" condition with no indentations that might indicate a possible wrecking of the bike in the past. Some good news so far at least.

I believe in percussive maintenance.

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01 Jan 2015 13:40 - 01 Jan 2015 13:43 #657526 by loudhvx
Replied by loudhvx on topic 1981 KZ550-D1 Forks
It's not necessarily the end even if there is a little tweak to the front end, if it's minor enough. On my first gpz550, it was wrecked before I bought it, and the forks were very slightly bent, which could only be evident from rolling the fork tube on a flat surface (I didn't know about the method of turning them in the fork clamps back then). But it rode fine. After another crash (this time with me on it), the forks were bent enough that I could tell in the steering. I straightened them in a hydraulic press and it was fine again. Then after another crash, the forks were pretzeled. Replacing them with straight, used ones, and replacement triple clamps, didn't feel any different from when I had the slightly bent ones.

I made a small jig to check triple clamps, but never tried to straighten those.

If you can, rotate the forks so that the bend causes the forks to angle forward slightly. That will increase trail, rather than decresing it. This will enhance stability, if affecting it at all.

The main problem with forks nowadays is that the inside diameter of the sliders are probably out of tolerance, and you can't get new bushings for the lower end of the fork tubes, so there will be a bunch of slop anyway.., way more of a problem than a very slight bend in the tube.

Forking by Frank, may be out of business. But they may have been the last place to get new tubes made.
Last edit: 01 Jan 2015 13:43 by loudhvx.

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01 Jan 2015 17:52 #657544 by SWest

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