810 kit for the KZ 750 motor.

Does anyone have any dyno numbers for a KZ 750 with a 810 kit?

I hope you can read German, but on this website you will find a few of dyno-sheets with various mods to a Kawasaki Zephyr 750 engine...
This engine is basically the same as the old KZ 750 engines.

Click

A long story short. A standard Zephyr has about 60 hp on the backwheel. The modded Zephyr now has a whopping 93 hp at the backwheel!!!

But that takes a bit more than just the 810 kit...

100 PS = 98.6 SAE HP

With any luck this link will give you the translated page.

www.google.com/translate?u=http%3A%2F%2F...e%7Cen&hl=en&ie=UTF8


Appears to to have taken the following.

810 kit.
Head ported, combustion chambers polished, milled .020"
83-85 GPz750 cams
Keihin FCR 35mm carbs
ZR7 headpipes with some other type of muffler.
Dyna coils
K&N filters


And lots of tuning.

Hey Steell - Thanks for the calculation. I'm married to a squarehead (for her self nick-named German heritage) and wouldn't even attempted any translation.

As you know I my platypus-hybrid has a ported and milled 650 head with GPz cams, Gpz intake valves, stiffer springs and Wiredgeorge prepped Mikuni 29's sucking through velocity stacks, Dyna coils and Dyna electronic ignition and MAC pipe. My reasonable guess would be around 90 ponies for my setup.

Keeps me smilin' whatever it actually is!

Cheers-Colin Firth -Ontario Canada

How about putting it on a dyno and posting the numbers?

Ituen wrote:

How about putting it on a dyno and posting the numbers?

Are you offering to pay the cost of the dyno run?

My impression is that reborn650 feels his bike is fast enough to be lots of fun, and that's all that matters to him.

And I happen to agree with his philosophy, dynos are for tuning, unless you put two different bikes on the same dyno one after the other, dyno comparisons are useless.

Quarter mile times are a different story, but even that depends on the rider to a great extent.

I'm in process of doing mine,to me horsepower is just a bragging rite, as long as it's a bunch faster I'll be happy

I'm just looking for hp numbers before I spend anymore money on my piped and jetted KZ 750. I want to be in the 100-110 whp range and it looks like the 810 kit isn't going to get me where I want to be. Time to look at alternative motors.

Stock 83-85 GPz750 is 85 hp at the crank, 810 kit alone will add about 10 hp with proper jetting (~10% increase in displacement plus compression increase), with additional increase in compression by milling the head .025-.030", head porting, and decent exhaust, the guys roadracing the GPz750's say they are getting 100 rwhp.

I believe 110 rwhp is possible with the right cams in addition to the above, but it will take a really good engine builder to do it

I figure around this time next year I'll know whether I am good enough

I have enough parts now to build three motors, so my plan is to do it in stages.

Stage 1
KZ750 cylinder block and milled head with mild porting.
GPz750 standard pistons.
GPz750 cams
Fuel injected with GPz750 Turbo throttle bodies

Stage 2
GPz750 cylinder block with fully ported and milled GPz750 head.
.020" oversize GPz750 pistons
GPz750 or MegaCycle cams (I haven't decided yet).
GPz750 Turbo Throttle bodies

Stage 3
This one will be based on the results of the first two motors, and is going to be an all out hp motor with the biggest valves I can stuff in the head, an 810 kit with coated pistons, bigger throttle bodies, etc.
I'm hoping for at least 120 rwhp, but I won't know till I get there.

I have been working for four years to get my shop to the point where I can now do all my machine work myself, while collecting parts for this project at the same time, and I'm finally there

The 80 KZ750E is not going to be my daily ride (I have my 750 twins for that), it's not going to be anything but a back road go fast bike.

I have been working on installing the Suzuki front end and Gpz750 swingarm the last few days, next week I'll do the frame bracing, and then start on the stage one motor (just got to come up with the $350 for the cylinder hone, tough when I am unemployed at the moment).

There is already one 110-120 rwhp 750 here, my Nephew's (GPzInfested) GPz750 Turbo

What would a lightened crank do for your HP numbers? It should take away some of the low end grunt, but allow higher /faster reving and give her some more top end right?

I have always heard when looking to get the most out of a motor you need to remove rotating weight.

Is the 83-85 GPz750 turbocharged or naturally aspirated?
Boosting the compression to 12:1 or 13:1 may help too on the 810 kit, but I'm thinking a KZ 900 motor or 1000 swap. www.kzzone.com has a ton of parts. Big block motors too.

hardr0ck68 wrote:

What would a lightened crank do for your HP numbers? It should take away some of the low end grunt, but allow higher /faster reving and give her some more top end right?

I have always heard when looking to get the most out of a motor you need to remove rotating weight.

Removing weight from rotating parts will increase the engines ability to gain revs faster . It does not necessarily increase HP . Dynojet inertial dynos will show it as an increase because the bike is able to accelerate the drum faster , a brake type dyno will not show an increase because it will still take the same load to keep an engine at a specified rpm . I had an R6 racebike that I removed the flywheel from . It showed about a 2hp increase on a Dynojet . It made a pretty big difference on the track too . I had to go down a tooth in the rear because I was getting into the rev limiter in places I hadn't been before , on a track that I have a few thousand laps on .

You don't loose or gain lowend or topend , the curve is pretty much the same . It will actually feel like there is more power at low revs because the engine will accelerate quicker from all rpm .