Nola wrote:

531blackbanshee wrote: curious as to why you would put bronze pivot bushing in place of the needle bearings ????

leon

I plan on riding it somewhat aggressive but not right to the edge....so I was thinking based on riding style, ease of maintenance, and with everything else I'm doing to it the bushings would be suitable?
I'm not that informed on the needles though, and would welcome your opinion.

Cheers

the early 900's had bushings,the later bikes got needle bearings.
sooo,did kawasaki consider it an upgrade??? i don't know...
but no other later kawasaki's returned to bushings,they all have needles or a combination of ball bearing and needles depending on the model.

if you plan on "spirited" riding i would consider a stiffer swingarm to be the first handling upgrade.
as the seamed tubing used in the swingarms is slightly stiffer than a noodle.
and, when pushed hard is the biggest cause of instability imho.
i have 3 78 z1r's and one 80 z1r and have never felt that they didn't stop well enough.
so you may want to get the stock brakes up in working order and decide then if you want to upgrade or not.

here is a pic of my 80 z1r which i custom built a braced chromoly arm to deal with my "spirited"riding.


i have a little too much tire(190mm wide)but i like the look and love the stability of the braced arm and large contact patch.

as you can see i upgrade my rear brake to the blue spot r1 rear brake and can't tell any advantage over the stock rear brake.

leon

p.s. i do plan to convert my front end to a usd and matching r1 front wheel and brakes.
the way it sits now is the best handling kz i have ever ridden,my hope is that it handles and stops at least as good as it does now when i convert the front end.hth

Sorry Steve, not my meaning to hi-jack your thread. . . . .

Leon, drilling that long is out, it will not come out clean.

We are toying with the idea of taking the old pivot tube that has an ID of 16mm and an OD of 22mm and mill down the OD to ~20.01. Cut it in to two 20-25 mm long bushings and press them into the new pivot tube and secure them with a weld.

But that method depends on how hard the old pivot is hardened. If it’s too hard to mill our backup plan is to buy a piece of precision steel tube with a ID 16 and mill the outside to ~20.01 and go with that.

The beauty of your top-hats is that then we don’t need to fit a stopper onto the swingarm studs inside the frame which was a part of our original plan.

/A

That's the set up. I'll send you a PM about the price of the top hat bushings.
Steve

scubaanders wrote: Leon did you mill the tophat's out of aluminium or steel? I am considering milling a bushings of my old pivot tube and press then into the new 20mm pivot tube, one on each side. But you solution is really nice and the tophat's will keep the seals in place.
/ A

i used 6061-t6 aluminum.
trying to drill or bore long things like pivot bushing is very hard to do and keep the tolerances to something usable.
so i developed the tophat bushing to get away from long bushings.
when in all reality you only need the bushings in the ends to match the od of the pivot bolt.
i've done zx and fz1 arms that way with good success.



leon

Leon did you mill the tophat's out of aluminium or steel? I am considering milling a bushings of my old pivot tube and press then into the new 20mm pivot tube, one on each side. But you solution is really nice and the tophat's will keep the seals in place.
/ A

floivanus wrote: On the zx6 arms there are caged ball bearings on the ends and needle bearings nearer the inside

all the zx6/636 arms i have seen have one ball bearing to control side thrust on the chain side,and one needle bearing right next to the ball bearing and one needle bearing on the other side of the arm.
the needles ride on the center bushing with the races installed on it.

kzrider.com/forum/11-projects/539557-76-...200r-build?start=620
the busing in turn buts up against the inner race of the ball thus completing the stack.




i then turn out "tophat"bushings to reduce the hole to the kz bolt size,and act as dust caps.
which may work for you steve.




hth,
leon

You're right. The sprocket side has two rows of needle bearings. I'm just checking it out on the couch. I'll take a closer look on the bench tomorrow.
Steve

On the zx6 arms there are caged ball bearings on the ends and needle bearings nearer the inside

I went ahead and ordered it. $23 delivered, what the hell, something to play with. Just got it. Took some rough measurements. The stock one is 23" long and the pivot is 9 1/2". This one is 24" long and 10" wide at the pivot. I thought it was made of aluminum but it is made out of steel. That means I can grind the welds and make it narrower to fit inside my frame. The pivot bearings are caged ball bearings. I'd rather they be rollers. :dry: My stock pivot by measuring the outside threads is 15.15mm. The pivot shaft is 20mm on the new one. ID of the shaft is 12.26mm. In side of the stock arm at the axle is approx 9" This one is 10 1/4". It might be possible to bore the new pivot shaft to fit my stock one. There's a Kaman bearing close by so I might be able just get the bearings to fit my shaft.
This thing is heavy. Came by Fed EX. How they did it for $23 I have no idea. They'll get 5 stars from me. :woohoo:
Now I have something I can sink my teeth into. :evil: Pics in the morning.
Steve

I could never imagine that the sized swing bolt was going put up such a fight, we tried every trick up our sleeve to get it loose.



Unfortunately the garage is a wooden structure so we could not play around with hydraulic jacks to press it out, so in the end I went out and bought a second hand used oxy-weld kit to heat the little F#&@er out.



But the swingbolt continued to elude us to big time and finally it had to pay the final price as the oxy-weld kit contained a cutting torch.



This means that we didn’t get a chance to measure up the swing arm before we start fabricating the new distances and bushings we will need when fitting the Zephyr swing arm to the bike.
Tks. to this excellent forum we already know that the pivot is 230mm



In short, we have a used Gpz750R1 swing arm for sale that some think can be brought back to life with a little JB-weld.