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'79' shafty with a lot of vibration

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23 Jul 2020 12:13 #831282 by Greg Davis
'79' shafty with a lot of vibration was created by Greg Davis
Hi All, I'm new here but am a member of Kz1300.com. I recently purchased an "79' 1000st to have a rider while working on the 1300'
My question is the 1000 seems to have an unusual amount of vibration, reminding me of my old h1 500 it is strong enough to numb my hands
after a 30 min. ride. What could be causing this? any help would be appreciated. Thanks Greg

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23 Jul 2020 16:14 #831300 by Nessism
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24 Jul 2020 10:50 #831341 by Greg Davis
Replied by Greg Davis on topic '79' shafty with a lot of vibration
Assuming it is a twisted crank how would one go about checking for this? Require a tear down or can be done with indicator from the ends of crank or measure
pistons 1-4 at top dead center {just guessing on that one) I have a full machine shop, so not afraid of attempting much but would rather not tear it down
unless needed.

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24 Jul 2020 13:26 #831347 by krazee1
Replied by krazee1 on topic '79' shafty with a lot of vibration
Verifying that cylinders 1&4 are at TDC at the same time, and then the same check for 2&3 would eliminate a twisted crank as the cause of your vibration. Could be accomplished with a TDC finder or dial indicator through the spark plug hole along with a pointer or degree wheel. Unless your bike was subjected to full throttle starts with a sticky tire, a twisted crank on a 79 model would be unusual/unlucky. I think the twisted crank thing became more prevalent in the early 80s with the J motors. I did have a buddy that twisted the crank on a 1982 CSR1000, the result of drag racing. Have you checked to be sure your motor mounts are tight?

Mike

Former M.E. at Kawasaki Motors Manufacturing, Lincoln, NE
1966 W1 (the Z1 of 1966-50H.P. and 100mph!)
1974 Z1
1978 KZ1000 LTD
1976 KZ900B pile O parts
1980 KZ750E
1980 Honda XL250S (I know, wrong flavor!)
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24 Jul 2020 16:01 #831353 by ghostdive
Replied by ghostdive on topic '79' shafty with a lot of vibration
More details would help narrow it down; my 750 shaft was vibrating a TON before I balanced my carbs. It also may be that your timing is off!

Does it vibrate at a particular speed or RPM range?

1982 KZ750 Spectre - 6 speed swap, BS34s, 18" rear wheel

2001 ZX-6R
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  • hardrockminer
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24 Jul 2020 16:51 #831358 by hardrockminer
Replied by hardrockminer on topic '79' shafty with a lot of vibration
I was thinking the same thing as ghost dive.

I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.
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