timing jumping ?

My point was the guide in the valve cover takes slack out of chain between cams and moves them just a little which is figured into the cam timing,just like when you install the idler assemb on a reg kz series motor up to 1980.
Installing the tensioner before the idler or guide will roll the intake cam back as it takes up slack in the chain

Never heard of a KZ motor "jumping" timing, I don't think it's even possible without other major damage occurring first.

Do you have a Factory Manual and just didn't follow it? Or not have one at all?

Wonder what you broke when you put the cam cover on after the tensioner? If you're really lucky you just destroyed the tensioner.

Do a compression check and see how many cylinders have bent valves.

You can download the manual HERE

Ive watched it jump timing before nothing is broken. Ive read that these bikes are know for skipping timing on deceleration. Its all in spec. Ive redone the engine and ran fine before. But definitely sounds like timing is back off.

andyvr4 wrote: Ive watched it jump timing before nothing is broken. Ive read that these bikes are know for skipping timing on deceleration.

That info in incorrect, they are not known to jump timing. How exactly did you watch one jump time, I hope your not running the engine without the cam cover. When and if they do, which is very rare major engine damage occurs. I would say when you installed the cams you got the timing off.

Set the ignition to top dead center ,Pull the tensioner back out then pull the valve cover back off and check where the cams are in relation to the timing marks on sprockets and surface of head.
If the cams are where theyre supposed to be reinstall valve cover 1st then the tensioner.
Then run a leak down test on the motor if you have access to the tools,if not run a compression test on the motor to see if a valve or 2 got dinged.

andyvr4 wrote: Ive watched it jump timing before nothing is broken. Ive read that these bikes are know for skipping timing on deceleration. Its all in spec. Ive redone the engine and ran fine before. But definitely sounds like timing is back off.

Hell Ive drag raced plenty of these motors at stupidly high rpms with stock adjusters without having one jump timing,If an adjuster is going to back off that's when its going to happen at stupid high rpms when you shut the throttle off.
These motors don't have that issue under normal street use unless youre banging gears at 9500,which I personally cant imagine anybody doing on a stripped down stock motored cop bike. :laugh:
I think you've been reading too many ads on certain web sites,but hey as long as youre buying Im sure they will also sell you a billet 2nd gear/1197 kit and some nitrous as long as your looking to spend money! :woohoo:

I'm with wireman on this. I have spun these engines way beyond redline many times even ones with loose timing chains and never had them "jump timing."

I just put my engine back together last night, and I saw that there is only 1/16" of clearance between the timing chain and the edge of the cylinder head / cover. With the tooth height at almost 1/4" - it is virtually impossible for the chain to skip time without destroying the upper cylinder head and cover. Now it might be possible to jump down around the crankshaft, but the chain would have to be so slack that the adjuster would not even take up the slack.

I propose that something else is causing the symptoms that you are describing. I just don't know what. Good luck.

andyvr4 wrote: Ive watched it jump timing before nothing is broken. Ive read that these bikes are know for skipping timing on deceleration. Its all in spec. Ive redone the engine and ran fine before. But definitely sounds like timing is back off.

In my 36 years of owning a KZ650 and being around other KZ's I've never heard of a KZ650 or KZ750 skipping timing. I don't know where you read that they have that type of problem, but I would be careful about believing things printed by that source. (Was it a Yamaha ad? :laugh: :laugh:) Ed

Maybe my factory 30 year old tensioner gave out so ill update when the manual One is in

Maybe when you installed the valve cover after having the tensioner already installed something got moved inside the motor,since that's the only thing that could happen in that situation.
Its like the old saying about the unstoppable force(valve cover and guide)met the unmovable object(cam chain/sprockets and tensioner)

andyvr4 wrote: Sounds like timing is off because of the sound when it turns over.

Are you sure it doesn't sound like an underpowered starter motor turning some binding-up starter gears? Have you charged your battery?

Can we hear it?