750 motor in a '78 KZ650 frame?

From all the info I have gathered which is not much a 750 four will drop right into a '78 Kz650 frame?Is there any thing that will be a total pain or is it pretty straight forward?Any help would be greatly appreciated.
Thanks
Craig

This swap is an absolute no brainer, it will drop right in. The only possible issue that you may encounter is with the charging system being a little different but you can just attach the 650's charging system to the 750 motor.

thats what i have gathered so far just wanted to double check.is the 650 system to weak for the 750?

Same basic system, it's just easier to swap the stators than it is to adapt the wiring to fit.

The 650 has a points ignition and the 750 will have an electronic pickup ignition with an IC igniter. You will have to do something to work through this difference (not too big a deal). As well, the 750 came with a 630 chain and the 650 had a 530 chain - not a big deal, but will require a new sprocket.
As well, the 650 has smaller carbeuretors than the 750 - don't know if you can use the 650 airbox or not, but you could easily go with pods.
Nothing here is really a big deal, but nice to plan for from the start.

This is a coincidence. I've got a line on a 83 GPZ 750 that I am considering trying to fit into a 78 kz650SR. From What I've heard it should fit pretty well. What bike is your 750 from?

gargoyle wrote:

This is a coincidence. I've got a line on a 83 GPZ 750 that I am considering trying to fit into a 78 kz650SR. From What I've heard it should fit pretty well. What bike is your 750 from?

Already did the 83 GPz750 motor into a 79 KZ650SR swap

Just be aware that you are either going to have to get a custom offset 530 sprocket made, or use a stock 630 sprocket and 630 chain. The 83-85 GPz750 has a 5mm-6mm offset sprocket stock.

And probably a Pingel petcock, on the SR the stock petcock hit the carb.

It's also easier if you use the 650 stator and reg/rec, and 650 ignition (or Dyna S), unless you can get a GPz750 wiring harness to steal the plugs from.

If you use the GPz750 carbs, you'll need the GPz750 throttle cable, the 650 cable wouldn't fit the carb throttle lever (on the 79 SR anyway).

Does make that 650SR scoot right along though


Oh yeah, the GPz750 (or KZ750) airbox will fit the 650 frame.

The GPZ750 Is almost complete including wiring. It's missing the tank and all of the fairings. They were lost in a fire while being painted.

The 79 KZ650SR has not only the 83 GPz750 motor, it also has the GPz750 front end and rear swingarm converted to dual shock

Give you any ideas?

Front end required only a bearing swap, swingarm required dilling the frame pivot bolt holes to 17mm, and cutting the monoshock mounts off the bottom then welding them on top for shock mounts. Really easy conversion.

Hardest part is mounting a headlight and doing all the wiring

Got the motor everything is going smooth so far.Quick question I am putting the points system in from my 650 just temporarily to get it running do I need to change out the part of the stator that is bolted to the crank or can I use the one on the 750?

The stator abd rotor don't have anything to do with the ignition.

I don't know if you "have" to change it, we changed both though.

We used the 650 stator so we could use the 650 reg/rec to avoid modifying the wiring, so we installed the 650 rotor also.

man thanks you guys have been a ton of help:cheer:
I'm going to swap everything over so the wiring will be the same a little less headache.As for the chain and sprocket what is the stock front and rear sprocket need to be and as stated earlier in the thread it needs to be a 630 chain and sprockets correct?