wobble at 87 mph

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13 Aug 2009 04:25 #313552 by 9am53
wobble at 87 mph was created by 9am53
Howdy, I was speeding on the highway today and found a little wobble when I approached 87 mph. I powered through it and the bike was perfect from 87 all the way up to 110 when backed off...is this a high speed wobble I keep reading about? or do you need ot be going faster to experience that. I thought maybe it was my lunch and work gear in my saddlebags but thought it would get worse with speed if it was that.

btw: I have an 82 1000LTD, no windscreen, and shoei saddlebags as I mentioned

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13 Aug 2009 06:09 #313570 by 650ed
Replied by 650ed on topic wobble at 87 mph
On my '77 KZ650C1, I recently replaced my Michelin Macadam tires with Pirelli Sport Demons. The Macadams had about 6,700 miles on them and they were the source of a high speed (90+ mph) wobble despite being properly mounted and balanced and having much tread left. Below 90 mph the wobble was not noticeable, but even though I only hit 90+ occasionally the thought of the wobble waiting there for me was unnerving. I replaced my bike's wheel bearings, steering stem bearings, and swingarm bushings in trying to eliminate the wobble; I already had new top quality shocks. I'm glad I replaced these items, and doing so reduced the severity of the wobble somewhat, but these items obviously were not the source of the problem as it persisted. After replacing the Michelins with the Pirellis the wobble is eliminated. I have taken the bike up to an indicated 120mph and it is completely stable. As a bonus, the Pirellis have better traction, particularly in braking, than the Macadams. I used a 100/90 V 19 on the front and 120/90 V 18 on the rear using new Metzeler tubes as recommended by Pirelli. These are the same tire sizes as the Macadams I replaced. I have only put about 700 miles on the new tires, so I cannot give a long term opinion, but so far I really like them. I have not yet driven in the rain so I reserve judgment there. These tires have a modern asymmetrical tread pattern similar in appearance to some radial tires. The link shows the tread pattern. I bought mine at Ron Ayers. Ed


Pirelli

1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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13 Aug 2009 06:18 #313572 by 9am53
Replied by 9am53 on topic wobble at 87 mph
I have an older (but in good shape) metzler on the front, and a new kenda on the rear. I don't think it is the kenda because I had a set of the same kendas on my 550 and I took it much faster than 87 MPH and had no issues. I suppose it could very well be the front tire!

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13 Aug 2009 07:08 #313579 by violentvintagecycles
Replied by violentvintagecycles on topic wobble at 87 mph
Could be the combo of old and new tires too.. Put your bike on the centerstand, front wheel in the air, and push the handlebars from side to side feeling if its loose and sloppy.. If it is, theres a spanner nut under the steering stem that should be tightened. Good chance its the tire tho.

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13 Aug 2009 07:12 #313582 by violentvintagecycles
Replied by violentvintagecycles on topic wobble at 87 mph
9am53 wrote:

I have an older (but in good shape) metzler on the front, and a new kenda on the rear. I don't think it is the kenda because I had a set of the same kendas on my 550 and I took it much faster than 87 MPH and had no issues. I suppose it could very well be the front tire!


Your crazy.. I bought a kenda rear tire for my honda 500 it was so hard of a compound it would slide in the dry.. Never buy one of them again. But im poor, so i still buy cheap tires, so for the kz i tried those new shinda tires.. Im very happy with them at the moment, and i also had that wobble. Combo of tires and adjusting that spanner no more wobble..

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13 Aug 2009 07:22 #313585 by 9am53
Replied by 9am53 on topic wobble at 87 mph
THe centrestand has been removed from my bike (PO) but the steering is much looser than on the 550, I will check that out too

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13 Aug 2009 08:13 #313594 by mzandmz
Replied by mzandmz on topic wobble at 87 mph
I think your wobble might be from a higher source, Telling you to Back off on the throttle and OBAY THE LAW! Hum,people dying on motorcycles...Speed related.... could be.:angry:

New to Family, 1979 KZ440 LTD

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13 Aug 2009 08:22 #313596 by 9am53
Replied by 9am53 on topic wobble at 87 mph
haha, Yeah I know. I do obey the law 99% of the time, speeding tickets cost $$! I plan on keeping my speeding to the track once I get some other kinks worked out.

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13 Aug 2009 08:26 #313597 by Sandy
Replied by Sandy on topic wobble at 87 mph
You might wanna look into a fork-brace.I know mine made a difference.
B)

1977 KZ1000 A-1

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13 Aug 2009 08:30 #313600 by N0NB
Replied by N0NB on topic wobble at 87 mph
Just remember, don't go 88!



Oh wait, that was in a Delorian. :huh:

Nate

Nates vintage bike axiom: Riding is the reward for time spent wrenching.
Murphys corollary: Wrenching is the result of time spent riding.

1979 KZ650 (Complete!)
1979 KZ650 SR (Sold!)
1979 KL250 (For sale)
1994 Bayou 400 (four wheel peel :D )

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13 Aug 2009 08:42 #313606 by mzandmz
Replied by mzandmz on topic wobble at 87 mph
That reminds me,, NOTE TO SELF.. Get Flux Capacitor fixed.Mines only putting out 1.18 jigawatts not 1.21 like its suppose to. Bummer:dry:

New to Family, 1979 KZ440 LTD

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13 Aug 2009 08:50 #313612 by BSKZ650
Replied by BSKZ650 on topic wobble at 87 mph
sounds like steering head bearings, if they are orig, then replace them with new ones, tapered style.
also tires out of balance, cupping and possible a rim that is not true

77 kz650, owned for over 25 years
77 ltd1000, current rider
76 kz900, just waiting
73 z1,, gonna restore this one
piglet, leggero harley davidson
SR, Ride captian, S.E.Texas Patriot Guard Riders.. AKA KawaBob

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