hardr0ck68 wrote:I did a quick search just cause i was wondering; and it seems both of these bikes have the same bore and stroke (66.0 x 54.0mm).
Soooo I think the ZR-7S is also a 8 valve head...my question here is are the pistons, rings and whatnot the same (or useable) on a KZ?
Basically these engines are the same. So it would be possible to use pistons, rings from a ZR-7 in an old KZ.
However there are a few differences between the engines.
The spacing between the carbs is different from the KZ-spacing, so if you want to put the ZR-7 carbs on your KZ, you would also need the ZR-7 carbboots.
I have heard (but I'm not really sure!!!) the cyl head is also slightly different, so putting a complete ZR-7 head on your KZ would only be a problem if you also want the KZ-cams in the ZR-7 head. If you use the complete ZR-7 head there should be no problems...
I also heard the ZR-7 ouputshaft is slightly shorter than a KZ-one. That's because the ZR-7 uses narrower sprockets.
The ZR-7 ignition is also different from the KZ or Zephyr ignition. The can't be interchanged without fabrication...
The ZR-7 engine also has a primarychain tensioner, so it should run a bit quieter. This is integrated in the oilpan and the engineblock, so you anly get this advantage if you use the complete engine...
The ZR-7 exhaust can be made to fit with some slight fabrication, but looks really good because its stainless steel... Take a look at the link in my signature for some pics of the exhaust...
