Twisting Frame

On my '76 KZ900, I've never experienced what you're describing so I'd have to agree with what everyone else has said. Check wheel alignment, suspension, etc. At 4K rpm I'm doing about 70 mph. (I'd be suspicious of doubling that because for one no stock KZ900 is going to do 140mph, may 110mph).

Bill

For what it's worth (which is not a lot), on a run today with my non-standard chain and sprocket combo an indicated 70 mph at an indicated 4250 rpm...

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

well, its getting to be winter anyways and i have another motor i wanna put in the bike. although the one in it is fast, cammed etc the other one is in better shape and i would like to tear it down and rebuild it anyways over the winter. as long as im doing this i may as well strip the frame, weld in gussets, new bearings, etc. if anybody knows of a site that shows basically how to rebuild this bike i will be very grateful. thanks, ryan

Garn wrote:

My guess is the swing-arm bearing loose/ worn.
Regardz

I remember my bike twitching or jerking as I went into and out of corners. New sprockets, chain, wheel bearings, swingarm bushings, shocks etc. and the transitions are smooth as a babies bum now. I seem to remember pictures Of a Roy-b-boy frame that was reinforced but he hasn't been around for a long time.

Post edited by: luvmykaw, at: 2005/10/19 11:24

I agree with Jeff,too.

Post edited by: Z-doctor, at: 2005/10/19 20:37

Do you have spoked wheels or aluminum wheels?
Loose spokes will give and you will feel a flexing sensation.

i have spokes, and i do notice that the wheel flexes side to side, i noticed this when i was checking the rear wheel bearing.

Check your spokes - you should not be able to flex the wheel/rim by hand. If the spokes are not tight then you are also probably looking at a rim runout problem/wobble.

put some good tires on it ,ditch the old worn out shocks they were outdated in 1976 .try a swingarm off a 77 or newer kz they have needle bearings instead of bushings,if you can find one with the double bearings on each side thats even better and put the rear disk brake on it while your at it.put a set of tapered bearings in the steering head while your at it.this should make a vast improvement in the handling,this is what i meant by letting your bike evolve over a period of time instead of just bolting in some big mountain and finding your self in trouble at 125 .it takes time,but youll get there!!good luck