Rear End Wobble

1980 kz1000E MkII. Owned the bike for the past 2 months. So after getting more familiar with it, I pushed it a little harder yesterday. Came round a bend that i have done several times with my (since sold) KZ1100 but this time, the rear end started to wobble. Was doing abt 60mph. Not a real sharp bend and i'm not an idiot on two wheels, but i bet if the guy behind me was paying attention he thought i was going to lay it down. Wobble wasnt too bad but enough for me to be concerned. I had replaced the spring shocks in the rear with Air shocks from another KZ. Tire pressure is at 40psi.Tires are newer. What should be the correct air pressure in the rear air shocks?I had them at 65psi. Can anyone tell me what might have caused the wobble? And better yet, What can possible fix it?

swingarm bearings and rear wheel bearings,either could cause this kind of reaction.

leon holmes
put it on the centerstand and unhook the shocks and shake the wheel from side to side and watch for play in the axle or swingarm pivot

I would reduce the air pressure in the air shocks. All the recommend pressure setting for my KZ air shocks are max 21psi in my 1100 and 41psi in my 750.

You can run more, but at those pressures, you are risking shock failure IMO, and at speed....well good luck!

all good tips...i run 35 psi in the rear tire at most 36 and i notice wobbles when my shocks are not up to par... post a pic of your bike and guys will know better how your set up is tied togehter.......40 is a tad high imo....

Thanx for the replies, i am going to take the advice and check out the rear wheel bearings and also reduce the psi in the rear shocks. I believe the air shocks are the same for the 750 and 1100 so it seemd like the weight of the bike determines the psi. With that said i'll split the difference between the settings for the 750 and the 1100.
Thanks all. Stay safe and cruise cool!!

I had the same issue and it ended up being a combination of wheel and swingarm bearings

Make sure your tire is aired up- really obvious I know but I ran into that problem once and the bike handled really goofy.

I also had my swing arm crack on the tube that the bearings ride in. It cracked on the bottom of this tube and had spread about an inch. I think it had an effect on my bike, so I put a GS1100 swing arm on it once I got the money for one. I did weld up the crack, but the bushings were toast afterward and I didn't want to bother with installing new ones in a cracked swing arm.

Of course, it could be bad bearings too, but just thought I'd throw in what I've experienced.

Running abt 30 psi now in the rear shocks and the bike definitely squats a little lower and seemed to want to hug the asphalt more. Yay!! I havent taken the same turn yet but i can feel the improvement. Thanks for all the feedback.

So a couple things led to my wobble. Just to fill everyone in so we can all learn from it. 1. Too much pressure in the rear shocks. 2. Notched bearing in the front end. These two issues combined at speed coming round a bend is what led to the wobble I am addressing the front end bearings and have already reduced the air pressure in the shocks.

I stated those pressures because that what is stated in the owners manuels as stock max settings.