wobbles at higher speed

Well first off dont ask me why im traveling this fast but my KZ1000 (and the XS1100 that im riding until i fix my 1000) both kinda get the wobbles at high speed. bumps do it, bends to it, but its worst when you hit a bump while going through a bend and kind of leaning into it. The whole bike sways back and forth pretty gently but its still really spooky. is it just because their weight? or do i have an off balanced wheel or a partially bent frame or anything like that? I notice it most when i leave home with 7-10 minutes to get to work

I would suspect that used tire you put on there first :dry:
A matching set is the way to go, then balance them.

If you have spoke rims check them for trueness , you can tape a piece of wire to a fork or shock and spin the tire to check for roundness and side ways movement

Tap the spokes to see if you have any dead sounding ones that need to be tightened up.
Please note; before you turn any spoke nuts make sure that you loosen up the rust by applying something like Kroil oil or PB Blaster for at least couple of days before you try and turn one or you risk the chance of snapping a spoke, believe me I know :blush:

Have you done any work to the front end?

If you have stock ball bearings they probably need grease or to be replaced with roller bearings, about 40 bucks through Z1E, "your best bet"
Note; if you decide to just grease them be careful and follow the shop manual instructions , they are loose and will fall out,

If you don't want to take it apart right now you can still tighten the stem nut some but not too tight especially if you don't grease the bearings.

Grease your swing arm, can you feel any sideways play ?

Loosen,adjust and re tighten the front end as per the shop manual's sequence.

Please be careful until you get it figured out.

JD




Sorry, I couldn't figure out how to make the pics bigger

Its just like this only WAY less violent. still enough to make your gut sink and jaw drop though no havent done much work to the front ends of either bike. My KZ1000 went into a speed wobble one night when i decided to top it out for the first time. the way i calculated it the speedo buries at 85 at 5500RPM. every 1000 RPM just before that seemed to work out to about 15 mph. i probably got it up to around 130 and when i let off the front end dropped really hard and the bike wobbled all over hell. It wasnt a real tank slapper or anything but at those speeds it made my heart stop for a second. The XS1100 seems to only do it while cornering. there was some play in the front wheel but it was because of a loose axle nut. The XS1100 has a broken valve on top of the left fork so theres no pressure in it. guessing thats a contributing factor? My KZ1000 seems to want to go into wobbles the whole time ive owned it. Even when i had brand spankin' new tires front and back. someone once told me the frames were manufactured with a defect but that sounds like total BS to me because the rest of the bike is built excellently.

and the bars dont jerk back and forth at all they just sway very gently at high speed while going around bends. usually starts to kinda do it at around 65-70mph.

I use to have a petty violent one at about 100 mph back before I parked it twenty two years ago.

Since I tore everything down and replaced all the bearings,brakes,tires and trued the wheels no more wobble.

But I don't take her over 100 very much any more,call it being in touch with my own mortality

JD

I had something similar, turned out to be the needle bearings in the swingarm pivot.

Mine had wobbles at about the 120 mark but I have not felt anything since I replaced my swingarm.

That was one of my problems.

Grease those swing arms !

I've been told by the experienced (old) guys at the Kaw dealer to keep my speed under 120 because of wobble. They say from 120-140 is kinda "interesting" on these old KZ's. Will these bikes really go that fast? They tell me my 1977 KZ1000LTD will do 160mph, or would when new. Seems a little ambitious to me.

But then again, there is a video of vintage racing on youtube from the late 70's of guys riding KZ1000's and they say they are doing 150+ around the course. They also make the point of saying that these are stock bikes just like you can go buy from the dealer.

The way I hear people talk these old bikes will go into an unrecoverable flat spin and blow up killing you and everyone around you at just a tick over 100mph.

74ullc wrote: I've been told by the experienced (old) guys at the Kaw dealer to keep my speed under 120 because of wobble. They say from 120-140 is kinda "interesting" on these old KZ's. Will these bikes really go that fast? They tell me my 1977 KZ1000LTD will do 160mph, or would when new. Seems a little ambitious to me.

No chance in hell of a 1977 KZ1000LTD that is bone stock and brand new would do 160. My dad bought his '77 LTD when it was brand new and it would do no more than 125. I have not tried top speed on my '76 900 but it hits 120 with ease.
The Youtube videos of the 70's and early 80's races said 150+ but they also said they were pushing 140hp.
Found the video to prove it!
He says it somewhere between 5:10 and 5:15

On topic: I don't see any major wobbles above 120 either!

Watch this Kitten Tooth...very good video about "wobble and weave" on our vintage bikes...



So according to Murray, you need to gain some more stones!

I sure didn't think they would do 160mph, but I wasn't going to try and find out on mine.

Here is the video I was thinking about. At 3:50 was the part I was remembering, he says they kept the style and look the same....but you're correct, they are not stock.