650/750 Valve Cover Compatibility

Hey Gang. Anyone have experience putting a late '70's Kz650 valve cover on an early '80's Kzk750 Head? The 750 (in the U.S.) had the reed valve pollution vent on the exhaust cam side and the 750 seems to have a slightly different bolt pattern from the top. Do the 2 extra bolts on the 750 valve cover thread into the head or are they shorter in lenght and only hold the vent cap cover to the cam cover? I am looking to keep my 650 cam cover if I decide to go with the 750 head.
Cheers-Colin Firth

I've attached two pics to explain

Here is the second pic of the 750 valve cover with the venting on top-Colin

Aside from the different bolt pattern, I believe that the raised portion in the center where the cam chain travels is higher on the 750 cover.

I was considering doing the same on my ZN since I have an extra 650 valve cover and also noticed the different bolt pattern. That in itself was enough for me to even attempt to try to make it fit.

The extra bolts just hold the little cover on, they don't go all the way through. The 750 uses a HyVo chain and has a cam chain guide on the inside top of the cover that presses down on the chain, and it is removable.

I assume this is the topic you originally posted in the other thread? Next time don't delete the subject line, leave it and delete everything else and I'll delete it for you. Made it awful frustrating trying to get to a post with no subject to click on

Aaaahhh....danged rookies when it comes to trying to cover tracks when a screw up arises:) I'll keep the editing info in mind steell-thanks.

I am planning on retaining the 650's original cam chain and accessories and putting the 650 sprockets on the 750 cams. So the 650 valve cover will fit on the 750 head-correct?

Cheers-Colin Firth-Ontario Canada

Post edited by: RetroRiceRocketRider, at: 2006/02/18 18:48

steell wrote:

The extra bolts just hold the little cover on, they don't go all the way through.....

Actually the two outer bolts (6x65) are different than the two inner bolts (6x22) and DO go through into the cylinder head (see pic below of my ZN....don't mind the dirt, I'm still cleaning the engine ).
And all the early 80's 750 models I checked on the Kawi site show the same.
I don't know if that would have any affect on securing the valve cover to a leak-free status or not though.
Do you think it still might work though, steell?
Because I'd be willing to give it a try as well to eliminate the rubber caps I have on the reed vent openings on my bike.

Had to repost because I attached the wrong pic...oopps! :whistle:

Post edited by: RetroRiceRocketRider, at: 2006/02/18 18:49

It's the 2 bolts towards the inside of the engine that are the shorter bolts and don't go all the way into the head on the 750 smog cover. A 650 cover will bolt right up, but you have to plug the ports coming out of the head that would normally go to the reed valve setup on a KZ750 smog cover to use a 650 cover in it's place or you'll have a major exhaust leak.

Where exactly are these holes located that would have to be plugged to prevent exhaust leaks? I don't have a Kz750 head to physically inspect, only a pic. If possible please circle the location and repost the pic if this can be done. Thanks-Colin Firth -Ontario Canada

reborn650 wrote:

Where exactly are these holes located that would have to be plugged to prevent exhaust leaks? I don't have a Kz750 head to physically inspect, only a pic. If possible please circle the location and repost the pic if this can be done. Thanks-Colin Firth -Ontario Canada

The ports line up with these protrusions on the cover.

I bought a valve cover that came off a Canadian GPz. They didn't have the smog stuff.

It looks like the Canadian head may still have the ports, though, because the Canadian cover still has protrusions to block the ports.