KZ750 LTD Cylinder head?

Hi Guys, I'm new to this forum and would like to pick someones brain? I have a UK spec Z750ltd that I got as a basket case. On looking to see if it was all there I note that the cylinder head is missing although the valves, springs, shims and cams are there. I have been looking on fleabay for a head but there is none out there.
Question: Would the head from the Z650 fit this engine?

Any advice would be greatly received

Regards Koj.

WHAT YEAR? ASUME IT IS A 4CYL?

The 650 four will bolt on the 750 four, but it will run a lot better if you put the 750 intake (I think) valves in it and do some porting. Use the 750 cams and cam cover though.

steell wrote:

The 650 four will bolt on the 750 four, but it will run a lot better if you put the 750 intake (I think) valves in it and do some porting. Use the 750 cams and cam cover though.

Yup, Steell is correct. I have a '77 Kz650 head on top of my bored 1980 Kz750 cylinders. My motor has Gpz cams and the bigger Gpz intake valves.

A machine shop will have to remove the old 650 valve seats and press in larger valve seats to handle the larger Gpz valves if you decide to go this route.

There are a lot of 650 heads out there for sale.

Cheers- Colin Firth-Ontario Canada

Cheers guys, thats a great help as so far I haven't been able to find any 750 heads for sale. Will the KZ750Ltd cam cover fit the Z650 head? What do I need to change to fit the Z750Ltd valves in the Z650 head?

Regards Colin:)

I am not familiar with the year of your 750 LTD or the 650 head you are looking to use. Chances are that your 750LTD was made after 1980 but I am not very familiar with the European line of Z750/4's.

The 650 and 750 valves are different

650 Inlet 33 Exhaust 28

750 Inlet 34 Exhaust 30

You will have to either enlarge the seats or have the old ones removed and larger ones pressed in to fit the larger 750 valve face. You will need to re-shim the valves.

Your 750 cams will simply drop in the 650 head.

You will also have to slightly enlarge the two bolt hole openings in the middle of the head that sit underneath the intake and the exhaust cams. These two bolts that connect the front and the back of the head to the cylinders are 7 mm. on the 650 cylinders and 8 mm. on the 750 cylinders.

But here is a little bit of background info that might help you out as well as a nice website devoted to the Kz and Z 650 models.

jarle.eltelevest.no/Kawasaki/Series/Z/650/z650.htm

The first year of the 750/4 was 1980 and the motor was basically a re-sleeved 650. Apparently Kawasaki simply dug into their inventory of 650 cylinder blocks to make the larger displacement. Everything was pretty much the same between the 650/750 from the cylinders downward.

If your 750 is a 1980 or 1981 then it has the single, roller-type cam chain. This is the same set up as all of the 650's from 1976 to 83. From late 1981 or early 1982 onward, the 750/4's switched to the HY-Vo chain set up.

The roller chain on the Kz/Z650 and early year 750's look like a bicycle chain while the HY-VO is a triple link set up. The roller chain was belived to rev a bit more freely due to less rotating mass from what I have read here on Kzrider and was considered better for performance.

With this HY-VO chain set up, the valve cover on the 750 was different as it had a rubber slipper that was built into the underside of the cover that acted as a chain tensioner. I believe this replaced the roller cam chain's top idler gear mounted on the top center of the 650's head.

Pull the valve cover off of your 750 and check the underside. If it has the rubber slipper on the inside middle, then you are going to need to use the Z750 valve cover designed for the HY-VO style chain.

If I am mistaken, hopefully someone will correct me on this point.

Hope this helps steer you in the right direction.

Cheers-Colin Firth -Ontario Canada

Post edited by: reborn650, at: 2007/09/07 22:51

Post edited by: reborn650, at: 2007/09/07 23:02

If your 750 is a 1980 or 1981 then it has the single, roller-type cam chain. This is the same set up as all of the 650's from 1976 to 83. From late 1981 or early 1982 onward, the 750/4's switched to the HY-Vo chain set up.

Not true based on at least three 1980 KZ750 motors in my possession.

AFAIK, all 750 four motors used the HyVo cam chain, and starting in 81 (some models, 82 all) 650's had the HyVo chain.

It is true that the head castings changed over the years on the 750's, the early models (1980 at least) still had provision for the roller chain slipper/guide in the head, thus making them the one to use when upgrading a 650 to a 750/810, while the later 750's lacked that feature.

Spend some time comparing part numbers and looking at the pics in the kawasaki.com parts diagrams of the different years and models of the 650's and 750's and you can verify this.

Being pretty much restricted to the house as a full time caregiver for my disabled Father for three years gave me plenty of time to do research online.

The easy way to tell if a 650 has the HyVo cam chain is to look for the kickstarter, if it doesn't have one then it is a later model 650 with a HyVo cam chain

Post edited by: steell, at: 2007/09/08 01:27

steell wrote:

If your 750 is a 1980 or 1981 then it has the single, roller-type cam chain. This is the same set up as all of the 650's from 1976 to 83. From late 1981 or early 1982 onward, the 750/4's switched to the HY-Vo chain set up.

Not true based on at least three 1980 KZ750 motors in my possession.

AFAIK, all 750 four motors used the HyVo cam chain, and starting in 81 (some models, 82 all) 650's had the HyVo chain.

It is true that the head castings changed over the years on the 750's, the early models (1980 at least) still had provision for the roller chain slipper/guide in the head, thus making them the one to use when upgrading a 650 to a 750/810, while the later 750's lacked that feature.

Spend some time comparing part numbers and looking at the pics in the kawasaki.com parts diagrams of the different years and models of the 650's and 750's and you can verify this.

Being pretty much restricted to the house as a full time caregiver for my disabled Father for three years gave me plenty of time to do research online.

The easy way to tell if a 650 has the HyVo cam chain is to look for the kickstarter, if it doesn't have one then it is a later model 650 with a HyVo cam chain <br><br>Post edited by: steell, at: 2007/09/08 01:27

I'll defer to Steell's research on this one.

My comment was based on the 2 1980 Kz750/4 heads that I once had and sold. They both had the provision for the similar cam chain idler gear as my '77 650. The presence of these mounting holes in the head led me to the conclusion that the motor was equipped with the 650 style camchain set-up.

With the dawning of a new day (and some much needed zzzzz's) I now recall that I did have to swap the camshaft sprockets from my 650 onto the Kz750's cams to make them fit my '77 roller chain set-up.

I had removed my comment that some of the later 650's came with the HY-VO chain because I wasn't 100% sure of the transition timeframe but as Steell indicated, the easiest way to tell if the later 650 motor had the HY-VO was the absence of the kickstarter.

Chalk one up for Steell's memory over mine:)

Cheers-Colin Firth-Ontario Canada

steell wrote:

If your 750 is a 1980 or 1981 then it has the single, roller-type cam chain. This is the same set up as all of the 650's from 1976 to 83. From late 1981 or early 1982 onward, the 750/4's switched to the HY-Vo chain set up.

Not true based on at least three 1980 KZ750 motors in my possession.

AFAIK, all 750 four motors used the HyVo cam chain, and starting in 81 (some models, 82 all) 650's had the HyVo chain.

It is true that the head castings changed over the years on the 750's, the early models (1980 at least) still had provision for the roller chain slipper/guide in the head, thus making them the one to use when upgrading a 650 to a 750/810, while the later 750's lacked that feature.

Spend some time comparing part numbers and looking at the pics in the kawasaki.com parts diagrams of the different years and models of the 650's and 750's and you can verify this.

Being pretty much restricted to the house as a full time caregiver for my disabled Father for three years gave me plenty of time to do research online.

The easy way to tell if a 650 has the HyVo cam chain is to look for the kickstarter, if it doesn't have one then it is a later model 650 with a HyVo cam chain <br><br>Post edited by: steell, at: 2007/09/08 01:27

I'll defer to Steell's research on this one.

My comment was based on the 2 1980 Kz750/4 heads that I once had and sold. They both had the provision for the similar cam chain idler gear as my '77 650. The presence of these mounting holes in the head led me to the conclusion that the motor was equipped with the 650 style camchain set-up.

With the dawning of a new day (and some much needed zzzzz's) I now recall that I did have to swap the camshaft sprockets from my 650 onto the Kz750's cams to make them fit my '77 roller chain set-up.

I had removed my comment that some of the later 650's came with the HY-VO chain because I wasn't 100% sure of the transition timeframe but as Steell indicated, the easiest way to tell if the later 650 motor had the HY-VO was the absence of the kickstarter.

Chalk one up for Steell's memory over mine:)

BTW Steve, any progress on the 1000 motor transplant into that 650 you picked up from sbjones?

Cheers-Colin Firth-Ontario Canada

i also have an 80 750 4cyl it to is a hyvo chain. so may be the used the old roller chain until they ran out then switched to the hyvo chain. that would make sence to seeing both. my engine vin is 000697

i also have an 80 750 4cyl it to is a hyvo chain. so may be the used the old roller chain until they ran out then switched to the hyvo chain. that would make sence to seeing both. my engine vin is 000697

The 1000 (1105) motored 650 (Ex sbjones) is still waiting on the CSR1000 donor bike that's in Omaha, and then is inline behind the Yamaha RT180, and that's after the GPz750 motored 650 SR is up and running (again).

That's the schedule for GPzInfested, I'm finishing up my KZ750 twin (again) and then working on the 750E (hopefully done by spring).

Things would go faster if both of us quit giving the Snap On lady our money

I just couldn't resist the set of 1"-6" micrometers and the dial bore gauge, and she has this really cool cylinder hone