That is an interesting question that I raised with a mechanic some years ago. His position was that in this application, bushings would be better. Since there is such a small range of motion at the pivot, any additional fiction that the bushing might have due to the greater contact area would be offset by the broader distribution of force that greater contact area would provide. If true, the bushings would last muc longer and would not create divots in the bearing race ( the correct term for that escapes me at the moment).
This sounded perfectly plausible to me.
Some precision machining would be called for, including creating a reliable way to insure that the bushing surface stays lubricated.

Want to be the guinea pig?

Steve, I didn't realize that I have needle bearings already. Maybe i should either leave well enough alone or upgrade to the later double needle bearing side ? Wouldn't needle bearings be better than bronze bushings anyway ?

I'd check Z1E and see if they have the same listing.
Steve

I have a pair of Bronze swing arm bushing left over from my H2 project and never used. Can these be used on my 77' KZ1000A swing arm ?

Original thought yes, 5.5” Zx6 6 spoke wheel.
I’m still doing research and collecting parts. I have a 6” wheel with 190 tire but haven’t checked to see if it will fit. The way things compute in my head, everything should be symmetrical and that’s why the arm offset at the pivot has me unsure. I’m going to run the dual rear shocks and it seems the mounts on the arm will have to be attached slightly off as well so that they center to the frame.
Before I start cutting limbs off the frame I want to be sure of my reasoning. Measure twice cut once.
I could just be overthinking this.....
read, research and ask questions. That’s where I’m at. Thanks for the help everyone!

Welcome Vinvar,

It's your bike so make it your own.
just try not to do a lot of things you can't reverse and keep your parts,
good tires and good shocks are the best mods
These stock bikes still ride real good after 40 years
Grease the swing arm

The owner of this head finished up drilling and tapping the head for the inserts on a Bridgeport - style vertical milling machine this past weekend. It went very well. For anyone interested, the spacing of the cam cap bolts (each cap) is 38 x 40 mm, and I'll have to go back out to the shop in a few days to get the spacing between the caps (I forget). It is bitterly cold here (-33 C overnight), so I've shut the main heaters off and left the shop at just above freezing until it warms up a bit outside. I'll sand / prep bodywork in the basement of the house, and fix tattered wiring looms in the kitchen until then....

A few notes....

1. We are going to run the studs through the H cover, just tall enough with drilled and spot faced cover, sealing washers, spacers, and external nuts and use them to hold the cover with a few of the original cover bolts blocked off (the owner's plan is to use 12 point ARP nuts for appearances). The studs will be installed thus: coat the stud threads with moly grease - turn the stud in by hand until it bottoms - back the stud out 1/2 turn - install cam bearing caps, washers and nuts - gradually tighten each nut 1/2 turn evenly until all the caps are fully seated on the head - torque to 8 ft-lbs. (96 in-lbs) in 2 stages - install top spacers above nuts - install cam cover and gasket- install sealing washers and top nuts - torque top nuts to 70 in-lbs.

Not for everyone, we know, but this is more a race engine than daily commuter. There are other ways to use studs without putting holes in the cam cover....I'll explain some of those in a later post.

2. We must use permanent thread lock adhesive (such as red Lock-Tite) when installing the thread inserts. We make sure each insert will fit properly (test fit) before cleaning the parts with contact cleaner, then apply the thread locking adhesive. The adhesive is necessary as the top of the holes where the Heli-Coils had pulled out didn't have much aluminum left to cut new 5/16 " UNF threads. The fact that our inserts go in all the way to the bottom of the holes, are one-piece solid parts of high strength steel, and are "glued" in place will make them much stronger than the original threads,

3. The owner was doing all the work drilling and tapping the head, and didn't take nearly enough photos. I was too busy cleaning and rebuilding old Amal Concentric carbs and trying to get rusted / seized Norton "Iso-Elastic" engine / transmission mounts, and swing arm pivots out of a bike that sat (and rusted) since 1986. I have to earn the money to keep the heat and lights going somedays. I'll get some photos of the faux milling machine set-ups and do a proper write up when the weather improves a bit.

4. The inserts still have to be test-fit and glued in place. The owner will order the studs from the manufacturer soon. For now we will be using the standard bolts to check our work. I also have to plasti-gauge the cam bearings to be sure the alignment of the caps is acceptable. If not, I'll have to work carefully to precisely correct or re-locate the dowel / knock pins. I'm hoping that won't be needed!!!!!

5. I will be using the same stud system on my own KZ-J 1394 big block and my "Beater II" 's new street / strip KZ-J 1170 engine (made out of discarded used / reconditioned racing parts). My heads don't have stripped threads, so no need to install the inserts. The studs will keep the original threads safe from damages over the harsh life my "experimental" racing engines will see in the future....

I had great fun sorting mine out. I fitted a Bandit600 wheel into GSXR600 swingarm with,I think, a 160 tyre, into my CSR1000 frame.
The whole process is in my build thread (somewhere!)
I started with centering the back wheel. I measured the clearance between the tyre edge and the inside of the frame downtube. Then subtracting the width of the chain,I was able to calculate the ideal position of the rear sprocket,leaving equal clearance either side of the chain ( I think I had about 4mm either side) . I needed to have about 9mm shaved off the sprocket carrier. That was it for the back end. Luckily the front sprocket turned out to be a standard sized offset.
A couple of things that came up. A lot of people seemed to think that the back wheel didnt need to be centered and could be run offset. This made no sense to me at all (and the fact that Harley do it on some of their bikes convinced me that it must be a bad idea!!)
I dont know the science behind it,others have their opinions about it but I wanted my front and back wheels running in line.
If youre using twin shocks rather than mono,keep an eye on the bottom of the left shock,you might have problems there with the chain.
And you may need some protection on the top of the swingarm over the pivot bolt, as the chain is prone to dragging on this.There are
different solutions for it.
That my tuppence worth. Good luck with it

I will take pictures of the ones I have sitting on my bench. They look like the remanufactured ones I can get from Z1 and the MAC kits I find for my bike don't show flanges in their kit.

Perhaps I should just build some passenger foot pegs to which I can mount the MAC exhaust. (the old ones were removed so I could put the GSXR Swing arm on.

Nessism wrote: It's really hard for us to say without seeing the bike and hearing it run. $4100 isn't out of line if it's in truly tip top condition. A lot of bikes out there though that run fine but haven't been updated via maintenance in most ways so the reliability can be fleeting. For example: original brake system with crud developing inside, original carb o-rings getting hard, stator getting weak, swingarm bearings have never been greased, and same for wheel bearings. Stuff like that takes effort and time and money to get right, and it's part and partial to purchasing a 40+ year old motorcycle. If you don't like working on old bikes I'd stay clear too. There is always something that needs doing it seems.

I have a few old bikes. Im familiar with upkeep etc. My question is mainly miles vs price. As someone said here in this post, 57k for 4100, is a lot. Ive done my research since I started this post. A bike that has 57k has either had a LOT of maintenance or not much at all. In each case, that can be bad: if a lot of tinkering was done to it, it could been done wrong. If NO tinkering was done to it. thats bad. Im going to pass on this bike. I dont need the headache.

I saw another bike, a 76 KZ900 for 4200. The seller wants at LEAST 4000 and wont budge on the price. Hes had it on cycletrader for a while. Its a beautiful bike, but it has AIRPODS and 4 into 1 exhaust, which is an immediate turn-off to me. Airpods can be a heck of an issue