Started on the rear end today so we are pretty much up to date now. Rear end isn't going to be as simple as the front unfortunately as the wheel axle and the swingarm axle are the wrong sizes. Decided to at least get the linkages sorted so that the bike sits semi correctly. I tried using the linkage from the ZZR but it was too wide at the mount for the shock. I turned it down on the lathe but still couldn't get it work so I dug up the original GPZ linkage and used the dogbones from the ZZR (phew, confusing myself now!) It all bolted up okay and I borrowed an 06 GSXR1000 rear shock from a mate of mine to see if it would fit. Funnily enough it does so I am going to leave it all as it is and start work on fitting the rim and swingarm correctly. Thinking I will need a shorted shock or start playing with the dog bone lengths. Worry about it later.

But hold on now! The needle bearings in the bikes swing arm are delicate little buggers.

First, let gets one thing strait. The pivot tube will when fitted be squeezed fixed in the frame when you tighten the swing arm bolt. Therefor we need bearings that will let the swing arm to pivot around the swing arm bolt.
So the swing arm which is made of ordinary steel is not hard enough to act as a racer for the bearing, therefor the needle swing arm bearing is fitted with an outer racer made of hardened steel and leaving the needles open on the inside. The needles are then supposed to use the pivot tube as the inner racer, there for the pivot tube is also hardened.

So when replacing them you need to dismantle the swing arm, pull out the old bearings, clean everything including the inside of swing arm tube.

Check the old pivot tube for rust, wear and pitting where the needles has been riding. If pitted or badly worn you will need to replace the pivot tube otherwise the life span of your new bearings will be short.

When everything is clean you try to fit the bearings on to the pivot tube in order to make sure they fit, they shall slide on nicely without use any force and you should be able to rotate them without force.

When you are certain they fit you can pull them of the pivot tube and fit the bearings in to the swing arm. Again no real force shall be needed, just a lite tap with a plastic hammer. You can use one of the old bearings as a mandrel. If they get stuck you haven’t cleaned out the swing arm tube properly. Pull out, re do it right and start again.

Whacking the bearings or pivot tube in place makes me curious about what profession you are in.

Needle bearings should always be handled with care, they are as fragile as your best friend.

/A

Ok no problem but if you want you could goggle the 2 models and look at the pics and descriptions. I have a 78 b2 with spoked wheels, single front disc, drum rear etc........ Assuming this but......(If the bike in your profile is not your bike then never mind)

And my Clymer and factory shop manual does show 4 bearings for the 78 KZ650 b2..

KZB2 650 wrote: Pretty sure that's a 1977 kz650 C1 with the mags, dual front discs and round master cylinder ??..... and if it does take 2 bearings instead of 4 it seems like it would have a step where the bearing would stop when you put it in the swingarm ?.... maybe thats why , the inner two are jammed up from it ...... not sure I've had mine off and cleaned and re packed em but never took em apart.

Edit......I just looked up swingarm parts at Partzilla and they showed the 77 C1 with the bronze bushings and not bearings..... maybe some one changed em out ?

My bike is the 78 b2

The needle bearings were a upgrade. When I did mine back in the day, they were pricy and new. I went with the bronze. 30 years later, I'm due for new ones. If my swing arm mod works out I won't have to. It has double needles in it already.
Steve

Pretty sure that's a 1977 kz650 C1 with the mags, dual front discs and round master cylinder ??..... and if it does take 2 bearings instead of 4 it seems like it would have a step where the bearing would stop when you put it in the swingarm ?.... maybe thats why , the inner two are jammed up from it ...... not sure I've had mine off and cleaned and re packed em but never took em apart.

Edit......I just looked up swingarm parts at Partzilla and they showed the 77 C1 with the bronze bushings and not bearings..... maybe some one changed em out ?

ezrider714 wrote: The sleeves are not meant to turn inside the swing arm, it should remain stationary, thus the need to press them in with the bolt /washer/nut tool. This sleeve is in essence the outer race of the bearing set-up The needle bearings rotate on the sleeve on the O.D. side and on the bolt that goes thru the frame/swing arm itself. On the I.D. side.In essence the Inner race That is the way i have always seen needle bearings operate

I think you mean the inner race,
Theres no reason the sleeve shouldnt turn that Im aware of anyway.

The sleeves are not meant to turn inside the swing arm, it should remain stationary, thus the need to press them in with the bolt /washer/nut tool. This sleeve is in essence the outer race of the bearing set-up The needle bearings rotate on the sleeve on the O.D. side and on the bolt that goes thru the frame/swing arm itself. On the I.D. side.In essence the Inner race That is the way i have always seen needle bearings operate

One more thing. On the diagram it shows bushings on the swing arm but I had only bearings. Can I use either or with this swing arm? It's the 1978 kz650b to be precise.

I also noticed when I had the sleeve and the bearings inside and decided to put it on the bike when I put the bolt through the swing arm and tightened it, it was hard to move the swing arm up and down. But when I loosened it it was a little easier.