GPz vs Spectre vs LTD/KZ

Ok, I was under the assumption that for most of the KZ bikes the standard and LTD had the same motors/cams/jetting for each bike for a given year. I was also under the assumption that the spectra was just a different paint scheme, but the GPz had hotter cams/different jetting.

Is this true? I read on another forum that they all have the same cams but then another guy chimed in and said the spectra's were a bit hotter and had more compression.

Can someone set this straight?

The LTD, CSR, Spectre, standard, and GPz all have the same motor essentially but the cams on the standard is usually a bit hotter than the CSR and LTD and Spectre, the GPz's cams are hotter still. The carbs are set to match the cams, the spectres have shaft drive, air suspension and 6 speeds. Later on the GPz's took on a major facelift with monoshock and some other goodies along with a different head (at least in the 1100's case) Regarding the spectres having higher compression and whatnot I don't think so, it was a cruising bike, so it had the specs of the other cruisers AFAIK. Other than cosmetic differences there are a few other mechanical things but essentially that's the most of it.

Seems that they do share components with the GPz...some info on cams/head/pistons etc about half way down the page. Spectre has higher CR, GPz cams, but they didnt get the 34mm Mikunis.

www.motorcyclespecs.co.za/model/kawasaki..._Z750N%20Spectre.htm

So, the standard KZ's are hotter than the LTD's??? I thoght these were the same...

I was toying with the idea of putting GPz cams into my 82 550 LTD and 80 750 LTD, but haven't found any for a decent price. Also thinking that the rejetting required might not be to doable since some of the jets for these two model carbs don't grow on trees.

On the KZ550's, the KZ550A standard had the same motor and cams as the KZ550C LTD. They are the same right down to the carbs (mechanical slide TK-22), except for the last year KZ550A, which used CV carbs.

The KZ550 D GPZ (81)had higher compression pistons, and hotter cams, reportedly better ported head, and oil cooler. The carbs were the same as the A and C (mechanical slide TK-22), but the main jets were two sizes bigger. Cosmetically, the carbs and motor were painted black.

The KZ550 H GPZ (82/83) had cosmetic changes to the motor. It is more squared off, so the valve covers are not swappable. Otherwise it is the same motor as the 81 D GPZ, with the only real change being that it had larger intake ports to accomodate the larger cv TK-26 carbs.

The ZX550 A Gpz (84-up) had even hotter cams with more duration, and the motor had different pistons to accomodate the cams. I don't know if ZX cams will drop into a KZ motor without the ZX pistons. The cam timing was 10 degrees (crank degrees) on the intake. The ZX used even larger cv TK-27 carbs. The ZX also was the first to use electronic advance on the ignition.

There is a KZ550 M which is a shaft-drive LTD. It used different cv TK carbs. I'm not sure if the motor was significantly different from the 550 C LTD other than the shaft and bigger intake ports.

The KZ550 F Spectre also used different cv TK carbs. I don't know much about the motor on the spectre.

Essentially, you can put KZ550 gpz (81-83) cams in the 550 C LTD, but without the higher compression pistons and head porting, it won't quite have the gpz power. An oil cooler would be a good idea, though. You'll need a gpz oil pan to add that.

home.comcast.net/~loudgpz/GPZweb/CamsKZZ...KZZXZR550500400.html

EDIT: the Spectre supposedly (according to Kawasaki.com) uses the same camshafts and pistons as the A standard and C LTD, so it's likely the same compression. The head does have it's own part number so maybe the head is different enough to raise compression, but I doubt it. I didn't check, but I'd bet the 550M shaft LTD would be nearly the same as the Spectre.

M357.5 wrote:

Seems that they do share components with the GPz...some info on cams/head/pistons etc about half way down the page. Spectre has higher CR, GPz cams, but they didnt get the 34mm Mikunis.

www.motorcyclespecs.co.za/model/kawasaki..._Z750N%20Spectre.htm

compression ratio, yes

cams no

Blurb taken from the link....not sayin it's 100% accurate as I have no real experience, but there is reference to GPz cams being used in the Spectre. This is only pertaining to the 750, not sure about the 550 or 1100.

"There may be some gamesmanship here. The Spectre has most of the engine changes first seen on the GPz. The cylinder head has smaller combustion chambers, which raises the compression ratio to 9.5:1 from the KZ's 9:1, and the chambers have cast-in ridges that are supposed to swirl the incoming charge. The Spectre engine shares GPz camshafts. They have the same timing and lift, as the KZ models, but the cam lobes are fatter in the middle. They open the valves at a faster rate, which means the valves spend more time open, so to speak, and that gives more time and space for the mixture to come in and the exhaust to go out. The result is more torque, and better acceleration in the mid-range."

From what I've read, the 82 GPz had more aggresive cams than a KZ, faster ramps but similar overall lift ( could these be the Spectre cams in question as well ? ). The 83-85 GPz cams were more agressive yet with more lift as well. Can anyone confirm this ? Im curious as to which cams the 83/84 750L use too, I have a couple sets here.

As for the 750's.

Pistons are different between 9/1 and 9.5/1.

Spectre cams will be the same as the standard KZ.

You are referencing a British sight.
Some of thier facts are incorrect.
They also get some models (across the pond) that have different specs.
Like the GT,which is a shaft drive
and has a GPZ spec engine.