YZF 600 fork upgrade? problems

[simi_ed]

I am finally trying to put a set of 600 forks on to my 89 FJ. 

   I'm still having a problem with fork alignment and wheel bearings.  When I get the front wheel into position between the fork legs, with the top hat spacer & speedo drive installed, I still have ~ 1/8" (~3+ mm) of space between all the pieces.  If I tighten the axle to spec (47 ft/lb) there is a LOT of drag on the front wheel.

   I believe the wheel bearings are set to the correct depth, so I don't think that's the problem, and shimming the axle to address the excess clearance seems like the wrong fix for this problem.

   Is this normal?  I looked at the Yamaha parts diagram, and I don't think I'm missing any parts.  This feels like something else may be out of alignment, perhaps a triple clamp?  I have not measured the spacing between legs to see if they're parallel ...  Can a triple clamp get that twisted?

What type of clearance is 'normal' for this set-up?  I honestly didn't check the OEM parts when I dismantled the front end on Monday, and the last time the front wheel was off was 2 yrs ago.



Suggestions?

[the fan]

my YZF is a snug fit.

what triples are you using?

are all the components YZF?

with the axle loosely in place loosen 1 of the tubes in the clamps and slowly rotate it. watch closely at the spacing near the axle. The leg should turn smoothly and there should be no movement at the axle. test both sides. I have seen YZF front ends out as far as .008 on working bikes. If one or both are 'bent' You could easily pick up 1/8"at the axle.

[simi_ed]

Bill, I have a Marc Rittner Upper from FZR1000, Lower is FZR1000 (forged alum).  The fork legs, wheel axle, spacer & speedo drive are all YZF (17mm axle shaft dia). 

Good tip on checking the legs for straightness.  Randy T. offered the same opinion that I have a bent leg.  That's better than a bent lower triple clamp!

I'll take a close look after work today. 

Did someone say never to work on your bike 1 month before a Rally? 

Thanks!

Ed

[simi_ed]

More input from anyb:


Just so nobody thinks that that's a new thing....
We had a 4 foot bar with two opposing clamshells that we used to retwist the triple clamps back into alignment">

> I have watched Kent (from GMD) straighten my R6 triple clamps when they were bent and he does it by hand with a pipe that is  approximately the same length as a fork tube. I.e. they bend pretty easily.

Just so nobody thinks that that's a new thing....
We had a 4 foot bar with two opposing clamshells that we used to retwist the triple clamps back into alignment, back in the old days........
Still works today!

"Eyeball: Mark 1" is pretty good at discerning slight misalignments.
:-)

It's pretty easy.


1. Horizontally clamp the stem into a large, anchored vice.

2. Slide on the upper crown to the stem. No stem nut.

3. Slide each fork tube into the clamps.

4. Snug the upper and lower clamp bolts. Just snug enough not to allow distortion. Not tight! The tubes still have to be able to twist in the lower clamp.

5. Place a straightedge or reasonable facsimile across the bottom of the fork tube and another across the tubes, up against the upper crown.

6. Squint and sight along the 2 straightedges.

7. Using a long pipe or similar over the fork tube end, bend the clamps back into alignment. You will have to "overtwist" the tubes, as they will spring back.

8. When you can sight along the straightedges and they are parallel, loosen the snugged bolts and wiggle the tubes around and the resnug the bolts and recheck the alignment.

9. When the clamps are straight, the tubes will be naturally aligned and remain tight when the clamp bolts are tightened.

10. Presto. Straight clamps.

I don't know why people stopped doing that - I feel so old to know that!

--
Marc Salvisberg email: marc@factorypro.com
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[andyb]

Source:

http://www.factorypro.com/tech/fork tube,clamp alignment.html

(woulda posted it here first if I saw this prior to reading it on that other horrible place)

[the fan]

I wouldnt suggest using the fork tubes to do the twisting, but what do I know...*

Ed,
I have the dies to check and straighten 41mm tubes at my house. All it will cost you is shipping and a fork service to ensure that they are straight. If you disassemble the forks and ship the inner tubes asap I can test/fix them overnight and ship them back.

simply shipping the tubes shouldn't cost too much even 2nd day to 41076.

* for the record I have tuned / serviced 10 sets of YZF forks so far this year. all but 1 were bent close to or out of spec on at least 1 leg. I use V blocks and a digital dial indicator accurate to .0000 and recently calibrated. my squinter is not nearly as accurate.

[simi_ed]

Bill, you're too kind, and I may take you up on the offer to untweak the tubes.  Lemme see if they're out.

If they're f'ed up, we'll talk.  And I'll have plenty of time too.  I will need to go back to stock, get this trued up and try again after the rally.

Thanks!

Ed

[simi_ed]

Thanks to Bill & Randy, I found the problem!  Bent right fork leg. Talked to Randy T., he tells me I've got the right parts.  Time to straighten this out!

Thanks All!

Bill, if the your offer is still good, please email me at edthiele at dslextreme dot com and we'll work out the details.

Why shouldn't I work on the bike before a rally???


Ed