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"Squirrely" over 70mph
- Martynbiker
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- 1993 KZ1000P
I am going to give the bike another "going over" on Sunday afternoon, I will take 3 or 4 hours and inspect it minuteley from front to rear.
Have checked the tire pressures, they are bob on at 36psi.
Will recheck swingarm, steering, and wheel bearings......... although this time I will drop the rear shocks off the mounts to see if there is any play on the bushes/bearings on the swingarm.
May also do the "string check' to see if wheels are properly aligned, and also if chain has been maladjusted anf the rear wheel is 'tweaked' to one side.
Thanks for the Input fellow KZ riders.
Martyn
If you cant fix it with a Hammer....... it's gotta be an Electrical problem...
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- 650ed
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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 120 mph 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 put a little over 1,000 miles on the new tires, so I cannot give a long term opinion, but so far I really like them. These tires have a modern asymmetrical tread pattern similar in appearance to some radial tires (see link). I bought mine at Ron Ayers. Ed
Sport Demons
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- WABBMW
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- Let The Good Times Roll !
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Then I bought new tires and alloy wheels. Now the motorcycle ignores grooves, and the wobble is gone. The bike is totally smooth and stable from 0 - 115 MPH. I believe that the old tires were very poorly contoured, partly from wear, plus poorly designed when new.
For what it is worth, the original front 19" spoke wheel width was only 1.85", with a 100/90-19 tire. The alloy front wheel is 2.15" wide, and I changed to a 90/90-19" tire. The rear wheel stayed the same at 3" wide.
The motorcycle handles soooooo much better. It used to have a "rubbery" feeling as you change directions. In my opinion, the front wheel was too narrow for the tire width. Now the handling is very crisp.
TIRES make a huge difference.
Bill Baker
Houston, Texas
1982 KZ650 CSR
2008 Yamaha FZ1
2006 Yamaha FZ1
1977 Honda Supersport 750 four (sold)
1984 Honda Nighthawk 650 (sold)
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- TerryK
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I made a telescopic wand out of an old magnet wand. It has a small pin welded to each end, that fit into the center punch holes. Now I can get both sides of the axle perfectly aligned by comparing one side to the other. This cured most of the weaving.
This combined with a gusseted frame, stiffer aluminum swingarm, and a steering damper made the bike rock steady at 100per.
1977 KZ1000
GSXR swingarm and rear brake
WM6 rear Akront rim
Wiseco 1075c pistons
33 smoothbores
stage 3 Web Cams
Head porting
Dyna S ignition
Lockhart oil cooler
Wiseco header
1980 Z1R drag bike
1200cc
38 Flatslides, .
500' cams
7" slick
Dyan 4000 SP ignition
etc
Ontario, Canada
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- Martynbiker
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- 1993 KZ1000P
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\\\\My bike used to follow grooves in the road badly enough to make you need a diaper.
A man who understands! .......... :laugh:
If you cant fix it with a Hammer....... it's gotta be an Electrical problem...
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- trianglelaguna
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Martynbiker wrote:
WABBMW wrote:
\\\\My bike used to follow grooves in the road badly enough to make you need a diaper.
A man who understands! .......... :laugh:
1976 KZ900
2003 ZX12R
2007 FZ1000
2004 ninja 250R for wife
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- netcats
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They look cool but can realy screw up the stability in the corners or a straight line.
I ditched the Dunlops and went with the standard size Metzeler Lazertechs, best move I ever made. Rock stable now and high speed corners are what they should be.
You might check this out if you haven't already.
Hope this helps out,
Netcats
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- Zthou1977
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The stuff already mentioned (especially decent tires and decent rear shocks) make a lot of difference. Steering head bearings were conical type as standard, so should be ok. But even with the crappy run-flats it should handle better than you describe.
1977 Z1000A1, 1982-1986 KZ1000P (built from two piles of parts), Moto Martin Z1200 (trying to get it registered), 1977 Z650B1
Utrecht, The Netherlands
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- Martynbiker
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- 1993 KZ1000P
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Assuming the frame is straight, I would check that top box of yours. IIRC (I don't have one on my police bike) the original top box was not rigidly fastened but used a system with springs because a rigidly mounted top box made the bike unstable.
You are correct Sir! the topbox is mounted on the p;olice mounts and is moveable by 2 inches either side.... it was weird to me, I thought the topbox was the cause of problems so removed it... bike still same... so refitted it.
i think the problem is Tires... but i am pretty broke so will put up with thew weird handling for another 2 or 3,000 miles.
If you cant fix it with a Hammer....... it's gotta be an Electrical problem...
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- trianglelaguna
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my bike is completely different feeling than it ws yesterday in the rear.....it feels like i clicked my koni's up to passenger settings and is way smooth on tracking setting into freeway sweepers and 90 degree in town turns.....
go figure...see what it feels like in 50 miles....
1976 KZ900
2003 ZX12R
2007 FZ1000
2004 ninja 250R for wife
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- Galactica
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I am assuming you changed the tire yourself. I've never changed my own motorcycle tires although I could if I had tire irons. My question is, if you balanced them yourself, do you need a supply of different weights? And do you do it on the bike?
Ross
77KZ1000
76 KZ900
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- trianglelaguna
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1976 KZ900
2003 ZX12R
2007 FZ1000
2004 ninja 250R for wife
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