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Discussion Starter · #1 ·
I have a 1986 ZX1000 that I bought and I just got it running. It sounds great but it seems to have a lot of vibration...more than I think it should have. Vibration is fairly high frequency, like something at crankshaft speed.
The vibration is there with the clutch in or out, in gear or neutral.

Odometer reads 5800 miles but I'm not sure that is accurate. The bike looks a bit rough for that low miles. I ran a compression test and all cylinders are right around 160psi. I've synched the carbs after I rebuilt them. It runs good and pulls strong but the vibration is driving me nuts. I had one of these back in the 80's and I know it did not vibrate like this. I looked in the manual and see that it has a couterbalncer. Is it possible for the balancer to be out of time with the engine and add vibration instead of reduce it? The manual makes reference to an adjustment on the balancer but it makes a reference to noise rather than vibration, does anyone know how that adjustment works?

It looks like the engine is original to the bike and it looks like it's never been apart. None of the bolts are rounded or show any marks like they've had a wrench on them. Motor mounts are tight and secure.

Anyone got any ideas on what could be causing my vibration.
 

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Navy Vet Search & Rescue
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I'm not sure how many years it covered but there was a recall for the counter weight slipping and causing vibration on some J model engines. Mine is an 81 that I bought new in the spring of 81. After I had been riding it about 4 months I noticed a bad vibration. I took it to the dealer and they informed me of the recall. They didn't charge me for parts or labor to replace the crank and I payed them $40 to weld and re balance the new crank before it went it to prevent it from happening again.
 

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Discussion Starter · #3 ·
If they new about it in "81 I would hope they had it fixed in production by '86 but you never know. Thanks for the tip and I'll keep that in mind and hope to God that is not the problem....:)
 

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I agree but if they knew about it in 81 which they did since there was a recall you would think they would "fix" the problem then too. The reason I paid $40 to have it welded is because the dealer informed me that them replacing the crank at no cost was a 1 time deal and if it happened again I would have to pay all cost. Then, he promptly told me the crank that was going to be installed was an exact duplicate to the one already in it and just as prone to have the same problem again. Go figure.
 

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I don't think the zx goes back to 81. That is liquid cooled, is it not?

A miss can cause vibration so you may want to check that before you go internally.
 

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Discussion Starter · #6 ·
I don't think the zx goes back to 81. That is liquid cooled, is it not?

A miss can cause vibration so you may want to check that before you go internally.
It is liquid cooled. I've confirmed that it is hitting on all 4 cylinders so I don't think it's a miss.
 

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Discussion Starter · #9 ·
I had the left side cover off tonight and there isn't much in there to cause a vibration. Just a timing plate and the cam chain gear. No flywheel to speak of and I didn't see anything in there that looked amiss.

I went through the couterbalancer adjustment per the book but I really don't understand what that adjustment does. It did definately made some noise when I turned the adjuster like the book said that it would. However, it didn't make any difference on the vibration.

I'll pull the right side cover off next and see if i can see anything wrong in there.
 

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Discussion Starter · #10 ·
If all things, the whole issue was missing bar end weights. Someone somewhere along the line replaced the grips with foam grips and elected to leave the weights off. I found a used set for $6 in eBay, put them on and what a world of difference. I can still feel some vibration in the bike like in the foot pegs and the bars but it is 1/10 of what it was at the bars. It's not liquid smooth like a more modern bike but definitely livable now.
 

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Odd and normally useless information information department reports that occasionally the head pipes and exhaust attachments will loosen enough that they will vibrate the whole bike without actually leaking . Re-torque all engine mounting bolts while you're at it .

~kop
 

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Check the drive chain too. My '90 ZX10 had a very annoying vibration at 4000 rpm's and up. Turns out it was the chain had about 10 links that were badly stretched. So my chain was constantly going back and fourth from tight to loose as the chain circulated around the sprockets. Installed a new chain, bike was smooth as silk thereafter.
 
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