TOPIC:

I did not really know where to put this thread so I put it here. I have seen on different places that the 81 Jay motor has 102 horsepower and then I've seen it have 95 horsepower in other places. What is the actual horsepower on the 1981 at the crankshaft and at the wheel. Thank you very much

The answer depends on which engine and which model you are asking about.

There were basically three KZ1000 engines, and at least a couple of versions of each one.

First was the KZ1000 (1015cc) that was an outgrowth of the KZ900.
Next was the MKII (1015cc) that was an improvement of the previous version.
Finally, these engines were replaced by the so-called J engine (998cc). The change happened in 1981, except for the copcycles that waited until 1982 to get the new engine.

Each of these engines had slight variations depending on application. For example, the 1981/82 LTD and CSR were rated at less horsepower than the KZ1000J of those same years. Yes, there is a J model motorcycle and a J model engine. Crazy, eh?

So far as I know, Kawasaki has never publicly stated where the power is measured, but it seems that the general suspicion is at the crankshaft. Rear wheel measurements will be around 10% less.

The factory service manuals from this time period give HP and torque numbers for each model.  As TexasKZ said, they don't say where it's measured, but I'm guessing it's at the crank.

KZ1000, Mk1 and Mk2
1978 KZ1000A2A:  83 HP, 8.1 kg-m torque
1980 KZ1000A4:  93 HP, 9.1 kg-m torque
1980 KZ1000D3:  94 HP, 9.2 kg-m torque
1980 KZ1000H1: 96 HP, 9.1 kg-m torque

"J Motor" bikes:
1981 KZ1000J1: 102 HP, 9.3 kg-m torque
1981 KZ1000K1/M1: 92 HP, 8.7 kg-m torque

The internals of early motors were basically the same (say between the 78 and 80 KZ1000-A), but the carbs and exhaust changed between models.  I'm not sure where the extra 10 HP came from between 1978 and 1980 for the A model.  

For the 1981 "J" engine, the J1 looks to have different camshafts than the K1 (LTD) & M1 (CSR).  That probably explains the difference in power.  It may also have a different exhaust.

The LTD and CSR have shorter duration camshafts.


.

The "J" has an extra 0.9mm of lift on the inlet and 0.5mm on the exhaust plus 10 degree's duration over the Ltd and CSR (I have a pair of inlets for my build  )

DOHC wrote:

  I'm not sure where the extra 10 HP came from between 1978 and 1980 for the A model.  


 

The extra 10-ish hp for the 78 Z1R , LTD and later 1015cc bikes was mostly down the increase in carb size from VM26 to VM28.