Swingarm pinch bolt

So I was talking to a shop today about TIGing in my frame brace kit. First thing he mentioned is that 14 pieces is excessive.
He did mention that welding in a swingarm pivot pinch bolt is advised? WTF is that and what does it do? This is motorcycle shop that does kaw work and he states he has welded a lot of older kawi race frames.

I've never heard of that, and I've never seen one welded even on a KZ1000-S1. If that was a common practice or was necessary, I would expect the S1 race bikes to have it done. I wouldn't do it as I have never heard of a Kawasaki swing arm pivot bolt losing the locknut, but maybe some other members have a different experience. Ed

Well I can tell u that my brother never brace his drag bike frames. I did not know that people were even doing this till I join KZRider. I remember helping pulling the motors out and the mounts would always line up when reinstalling them.
Not saying it is not needed .....frame will flex under extreme load but if the bike is not meet for the sole purpose of drag or road racing I would not bother.

for drag racing may not be necessary. For corners it is needed.

Is this what you mean, when you say swing arm pinch bolt? Like those used on swing arms with eccentric adjusters???

I don't know your plans? But research the old Sandy Kosman frame kit for bracing.
Welding the swingarm pivot is for drag racing only! "Puppet" the infamous dragrace chassis builder said that, "of course" you have to weld everything together. These frames flex so much! Thats for high end street or drag racing!
Any road driving you need a good Suzuki GS 1100 aluminum with good bearings

Maybe he was thinking drag racing I can see that. I think I need to shop around for a different guy to weld in the kit. He shot me a ballpark figure of $400 to weld in a frame kit and thats with the frame stripped and ready to go.. That sounded a b it high to me. I don't want a crap job but $100/hour?

Can't see how you can fit a pinch bolt to the existing frame pivot without welding on an extended piece and using a longer spindle.
Never seen it done and it isn't needed.
Also 14 brace inserts isn't excessive if you are really going to push the bike ( just look at the extent of bracing on the Ac sanctuary race bikes )
I have 25 braced sections on my latest twin shock Moriwaki superbike build ( soon to be posted on projects ) and it does make a very noticeable difference ,even in normal road riding.
Fitting modern stiffer swingers and forks transfer more flex into the frame which needs addressing to make the mods more than just cosmetic.
If you can't get a straight answer from your welder/mechanic then go elsewhere.

zed1015 wrote: Can't see how you can fit a pinch bolt to the existing frame pivot without welding on an extended piece and using a longer spindle.
Never seen it done and it isn't needed.
Also 14 brace inserts isn't excessive if you are really going to push the bike ( just look at the extent of bracing on the Ac sanctuary race bikes )
I have 25 braced sections on my latest twin shock Moriwaki superbike build ( soon to be posted on projects ) and it does make a very noticeable difference ,even in normal road riding.
Fitting modern stiffer swingers and forks transfer more flex into the frame which needs addressing to make the mods more than just cosmetic.
If you can't get a straight answer from your welder/mechanic then go elsewhere.

I completely agree

I

One thing that is a joke on all the Kz900/1000 frames is the sloppy fit of the swing arm pivot bolt to the frame. Slide your swing arm bolt into the frame and see how much play there is. It is a joke. Its about .010ths to .030ths clearance. If you would have looked at all the factory Kz1000 Superbikes (even the S1's) that Mr. Muzzy built, they all had oversize swing arm bolts. I would check out every inch of the factory bikes for hours looking at every little piece they changed or made up.

I picked up that trick back in 1978 on the DesRoche built Vetter Superbikes. Any machine shop can make you a few. I used a adjustable ream to enlarge the pivot holes in the frame so the swing arm bolt had a super tight fit to the frame. Then had my machine shop hone the I.D. of the inner swing arm sleeve so the oversize swing arm bolt had zero clearance between the two. If you have .020ths play at the pivot bolt, just think how much movement there is at the end of the swing arm where your rear axle is.

Even on my S1 I went to a oversize swing arm bolt. When I first got my S1 it wobbled pretty bad. I was really disappointed in its handling compared to my homebuilt KZ1000 Superbike. There was a noticeable improvement in the handling of the S1 with just installing the oversize swing arm bolt. No more hinge in the middle feeling around fast sweepers!!!

Now a braced frame, a nice braced swing arm, beefier triple trees, good forks, and rear shocks, and a oversize swing arm bolt, your Kz frame should go around corners pretty good.

Good point on the swing arm pivot.
The same treatment with the engine mount bolts helps a lot too.

zed1015 wrote: Can't see how you can fit a pinch bolt to the existing frame pivot without welding on an extended piece and using a longer spindle.
Never seen it done and it isn't needed.
Also 14 brace inserts isn't excessive if you are really going to push the bike ( just look at the extent of bracing on the Ac sanctuary race bikes )
I have 25 braced sections on my latest twin shock Moriwaki superbike build ( soon to be posted on projects ) and it does make a very noticeable difference ,even in normal road riding.
Fitting modern stiffer swingers and forks transfer more flex into the frame which needs addressing to make the mods more than just cosmetic.
If you can't get a straight answer from your welder/mechanic then go elsewhere.

Moriwaki Superbike project!!! Can't wait to see it!!!

This is from I think Daytona 1979.



Sorry about quality of picture, I took a photo of one of my old pictures from back in 1979