I just got a Quadzilla (1988) and it vibrates horribly. I've had some 500cc dirt bikes and never felt anything like this. Is this normal, or is there a common problem on these (flywheel/clutch basket crankshaft, etc...) that causes them to shake.
Thanks!

 

first check to see if the timing marks are lined up correctly. crank to gear, gear to counter balancer gear. there is 3 marks that should all be in a row. then check oyur main bearings. grab the flywheel and see if you can move it up and down, and side to side.

 

Good advice... these shouldn't vibrate all that bad.
Either counterbalancer out of time (3 marks must line up, not just 2 (Common mistake)), or crank bearings/cases shot.

When you grab the flywheel to check for motion... get rough with it. up and down motion like your trying to lift the machine off the ground, etc.
ANY perceived motion of the flywheel = get out your wallet.

 

Good advice... these shouldn't vibrate all that bad.
Either counterbalancer out of time (3 marks must line up, not just 2 (Common mistake)), or crank bearings/cases shot.

When you grab the flywheel to check for motion... get rough with it. up and down motion like your trying to lift the machine off the ground, etc.
ANY perceived motion of the flywheel = get out your wallet.

 

Thanks Guys. I will check it out this weekend. Do either of you happen to have a service manual that you could copy the page out of and email me? I'd like to see what I am looking for.
Thanks,
Scott
s j g a d d i e @ r r a z . n e t (obvoiusly w/o the spaces)

 

go to www.everything2stroke.com they have a repair manual section there. maybe they have the 500.
i think you are on the right track with the counterbalancer and/or crank bearing problem. the flywheels are somewhat prone to failure, but when they fail, the bike wont run. (the rivets that hold the hub to the flywheel is what fails. ask me how i know... [img]i/expressions/face-icon-small-blush.gif[/img][img]i/expressions/face-icon-small-disgusted.gif[/img][img]i/expressions/face-icon-small-mad.gif[/img] )
good luck
aaron

 

Question: Why did you buy the thing if it vibrates so bad?

Obviously you knew something internal wasnt right....



Your problem is probably something relating to the counter balancer, or piston, crank, something expensive.
IMO, your crank bearings are out of round and you need a complete engine rebuild.
Typical quadzilla. They all do it. Is it cutting out at high rpm? Does it give you any indication of a major air leak?

 

Well, funny you should ask.....
First of all, I didn't really "buy" it. I traded some work for it, from one of my friends who usually has really nice equipment. I knew it needed a few things, but I have always wanted a 'zilla, so I took it. Anyways, I took off the stator cover, and there is some end play in the crank. I can feel it move but cannot see it, and there is no discernable up and down movement. I am draining the oil now, so I can check the balancer timing marks, and the clutch. I'll let you know what happens.

 

Some end play is acceptable, although you'll need the manual to measure/determine whats excessive. The bearing/boss issue is checked by up and down motion... ANY percieved motion in that direction = the bad news.

If you didn't feel any, and assuming you got pretty rough with it, your probably okay... Definitely look at the timing marks first.

 

Well, I got the clutch cover off.... I can move the crank up and down a small amount. I assume this is the problem, however I still want to check the balancer "out of time" idea, and I can only see two punch marks that line up. One on the drive gear (on the crank, closest to the center) and one on the balancer gear. Where is the third one?
Thanks for your help!!