KZ750E cylinder head options

I have to change the cylinder head on my kz750e as it is cracked and leaking oil. I will be looking for used ones on ebay to replace it. But my question is which heads can I use as direct replacement. I read somewhere that I might be able to use heads from zr750 Zephyr? I am not necessarily looking to gain any power. But just looking at the options on ebay, the heads from zr750 zephyr seems a lot newer and optically a better option. So will they work or are there other options? Some people have mentioned some things about pistons for kz750 and gpz750 being different - the latter being taller for higher compression. But I haven't found any info on the kz750 vs zr750 zephyr?

The later heads did away with the mechanical tach drive feature.

Thanks, good point. But as I do not have a tach on my bike, I do not see that as an issue. I am primarily concerned with whether I will have issues with piston clearance, cam chain or bolting on exhaust or carbs?

Don't know where you are located, but good luck finding Zephyr 750 heads...and the one or two I can see, don't look great. Zephyrs never sold well in North America. Many of the newer, good looking, ZR-7 heads (as other parts) are also advertised for Zephyr 750s, as they shared same factory designation ZR750.

.....the ZR-7 head may actually be closer to old KZ 750 than the Zephyr's, as the top cover is squarish whereas he Zephyr's were rounded, mimicking the ones on the original Z1 (900).

.......main difference between the ZR-7 and Zephyrs head, is the ZR-7 has top guide built on the head, whereas the Zephyr's had it in the valve cover. Head Gasket has different number also, but I believe is ZR-7 has tabs sticking out. Don't know why. The tensioner, and camchain guide were also different on ZR-7

I am in Denmark, Europe and it seems very possible to locate the Zephyr 750 heads.

Just looking at pictures I actually came to the same conclusion. ZR-7 heads actually look more like KZ750 heads. But can they be used, the ZR-7 heads? My main issue is that if I look for KZ750 heads I can only find very old (of course) and not very well maintained. But looking at heads from newer, at least from visuals, looks a lot more appealing. Some even seem cheaper as well.

How well do you know the difference of tensioner and camchain guide between ZR-7 and KZ750? And how about the combustion chambers? I am unaware about whether the dome of the zr-7 pistons are significantly different than KZ750 pistons?

I don't think anyone has done this. The piston dome affects compression. Because compression were same, would have to say pistons are about same. Believe head gasket number are different because ZR=7 has handling tabs, but think, and I repeat think, everythig is same.

....I believe it comes down to finding if camchain is same length. A matter of checking on part numbers. As to the guides, the camchain guide to tensioner is definetively different, meaning you would have to used the tenioner that matches the guide pivoting in cylinder barrels. Would the head care about that guide?? Probably not, but can't tell for sure.

Thanks a lot for additional information on this. It also seems to me like no one has actually done it. So perhaps if I can wait until winter it would be worth a try, but for straight replacement it is probably too risky.

How much do you know about the Zyphyr head? From what I can see I would need to buy the valve covers together with the head for the camchain tensioner. I would not be able to use my old valve covers. But the chain might work as is? Some people write that the Zyphyr head is better flowing, but there is also information about combustion chambers being different and the cams as well. So I am unsure about whether it would be the right fit for me. I really just want the torque and is not looking to rev high to gain a few HP.

This weekend im going to pickup a kz650 with a kz750 engine and a zephyr head. The problem is that its not running and the owner never got it running right.
I have a spare kz650 engine, but im going to try to fix the kz750 engine first. I can let you know my findings when i solve the problem.

This article has some 750 head info you might find useful.

members.tripod.com/gpz_rider/technical/FAQ2000.htm

Wow!! That is an absolute goldmine! Thank you so much for sharing!

Pindakaas wrote: This weekend im going to pickup a kz650 with a kz750 engine and a zephyr head. The problem is that its not running and the owner never got it running right.
I have a spare kz650 engine, but im going to try to fix the kz750 engine first. I can let you know my findings when i solve the problem.

Yes I would be very interested, so please let me know what you find.

I do not believe you would have any problem with the Zepnyr head. If there is any different in flow it would be insignificant. As far as I know, the only truly factory 'hot rodded' in KZ750 series was the GPz, with higher compression and hotter cams.

.....I have used KZ750 head gasket on Zephyr 750 and they are the same. Yes, of course, you would need the Zephyr valve cover, but not necessarly the cross wedge Zephyr tensioner. I use a manual one, not because the auto ever failed, but because the manual makes top end maintenance a breeze. To me a autotensioner is for those who do not understand tensioner, and do not perform maintenance.

..................it is little more risky, of course, because more uncertainties, but I think the ZR-7 head would work too, as long as camchain length is same.