Sorry Bangshift', the site or my coputer would not sumit an answer last night. Here's what I thought then.............
Bangshift', it appears you have something drastically wrong.
Check tyres for pressure, out of round. Wheels for wobbles.
Check swing-arm bearings by rocking the wheel and trying to force movement. Same with rear wheel bearings and (in particular) the rear sprocket bearing.
Check for tight spots in chain. Set the shocks to firm.
Check front steering head for looseness/ tightness.
Bounce front end up and down with the front wheel loosened, then with triple tree loosened.
Don't forget to retighten.
Take her around a known corner prior to this then recheck after on the same corner. Lastly, set the bike up symmetrically and view it from front and back. Try a long piece of wood (straight-edge) and check if distances are even.
My guess is the swing-arm bearing loose/ worn.

Regardz

You need to check a number of things.

Swingarm bushes - make sure there is no play on the swingarm.
Wheel bearings - you should not feel any movement of the wheel when rocked side-to-side
Chain alignment - do not rely on the chain adjuster marks - either get down on the ground behind the bike and visually line up the wheel, or run a straight edge or string alongside the tires to check alignment.

well i was going down the highway in 5th gear at 8500 rpms. i was definately going fast but i was wondering if anybody ever looked at the tach when they were going fast in 5th and would be able to approximate how fast i was going. and the swingarm bearings seem find and i just put on a new wheel with seemingly good wheel bearings. maybe the bike wasnt designed to be cornered like that i dont know, i have scraped the crash bars several times on corners like that so its defenately about as far over as it can lean. so maybe you could tell me some things to do for the bike for racing. thanks, ryan

when i go around corners fast, my bike seems to twist and "hop" around the corners, it is a 1976 kz900. its like the back wheel goes out of line with the front wheel and then springs back really fast, but all of the bearings seem fine, to me it feels like the frame or swingarm severely twisting, is this possible? if so can it be remedied? also, my speedo doesnt work and i was wondering what mph 8500 rpms would be, i believe i have stock chain and sprockets. thanks, ryan

Idle can be affected by leaking carb boots. I suggest, that as a matter of course, you just replace the ones you have and perform a tune as described in a shop manual or Clymers. Essentially:

1. valve adjust
2. cam chain
3. ignition timing - when you do this, check primary/secondary impedence on coils and also measure voltage to coils when you turn the key on and possibly replace plugs/plug caps and plug wires
4. sync carbs / set idle mixture

If you do the stuff I noted above, your bike will probably run fine. Go about it in the order described but, again, replace the intake manifolds if they are in doubt. Also don't neglect general lubrication; ae the swingarm, steering head bearings, chain and tightening all nuts/bolts and checking brake pads and function.

Greasing the swingarm bushing will allow you to keep more money in your pocket
Instead of spending it on repairs, and possibly medical bills

Kawasaki used several rubber bushings on the twins to keep vibration from getting to the rider, the handbars are mounted in rubber bushings, as well as the foot pegs. You might check those to make sure they have not disentegrated. The handlebar bushings are located in the upper triple clamp, and the footpeg bushings in the footpeg mounting bracket. If you can move the footpeg with your hand, then they are bad, and you can look at the top and bottom of the upper triple clamp to see if the handlebar bushings are falling apart.

If I recall correctly, there are two engine mounting bolts on top of the cylinder head, one at the front of the motor, and two at the back, all of those are tight?

150 psi is good compression if the engine is cold, normally, it's 160-175 if the engine is warm.

I have a KZ750G1 also
My mirrors do get a little blurry above 4k, but not to the point of being unusable, and the vibration is certainly not enough to be uncomfortable.
I assume that sitting on the bike and revving it above 4k in neutral the vibration is the same?
If torqueing the engine mounting bolts does not reduce the vibration considerably, then do a compression test and post the results here. You also might consider checking and adjusting the valve clearance.
Getting into the balance shafts is really a last resort, as you have to remove the motor and split the cases.
How many miles on your bike?

And my standard advice to anyone with a 76-80 750 twin:
Grease the swingarm bushings, the grease fitting is below the airbox, behind the right side frame rail, on top of the swingarm.

Post edited by: steell, at: 2005/10/15 05:05

I bought my first bike last winter and boy did I jump in head first. 78 KZ1000 basket case. I took it out by the armload. I had a friend who said he would help me with the project so I went for it.The motor was a 1982-1000J.This made for some interesting wiring issues when it came to the guages and controls, but not that bad. I had some charging problems and a few other issues that I finally got worked out and I actually got to drive it for the past 3 weeks. I love this bike. I got new fork seals put in but they started leaking almost right away. the tubes are in great shape maybe the springs are getting weak? Or maybe I should go with original Kawasaki seals? Anyway that is pretty minor. What I was really wondering about was the swingarm swap that seems so popular. When I bought the bike a GS swingarm came with it!

Last winter I built it this winter tear it apart again?
I really like the way they look.

This is a great site!