6SPEED IN A KZ750

ITS BEEN 3 WEEKS WITH THIS 6SPEED IN THE BIKE AND ITS WELL WORTH THE EFFORT AND I HAVE HAD ZERO PROBLEMS SO FAR I DID HAVE A GUY EMAIL ME AND SAID HE DID THIS IN THE 80'S AND SAID THEY HAD TROUBLE WITH 2 GEAR SHIFT FORK BENDING AT DECELERATION WITH A LOAD SO WE WILL SEE WHAT HAPPENS,AS FOR INSTALLING THE GPZ550 6SPEED IN THE KZ 750 ITS A DIRECT DROP IN.I USED THE COMPLETE TRANS OUT OF THE 550 SHIFTING FORKS DRUM EVERYTHING,THE ONLY THING I RAN INTO WAS THE SPLINES ON THE 550 SHAFT ARE SHORTER THEN THE 750 SHAFT SO THE CLUTCH HUB IS TO WIDE SO WHEN YOU TIGHTEN IT DOWN THE THEADS NEVER GET TO THE LOCKING PART OF THE NUT WHAT I DID IS GROUND DOWN THE NUT SO THE THREADS WOULD REACH THE LOCKING PART,BUT IF YOU USE THE CLUTCH HUB OUT OF THE 550 IT SHOULD BOLT UP JUST FINE.AS FOR THE OUTPUT SHAFT I WELDED THREADS ON MINE SO I COULD USE THE LOCK WASHER AND NUT TO HOLD THE SPROCKET ON.IM DUNNING A 14TOOTH IN FRONT AND 33 IN THE REAR AND MY RANGE PER TANK OF GAS HAS IMPROVED BY 50 MILES IM GOING TO TAKE A ROAD TRIP TO SEE WHAT KIND OF MILEAGE I GET I WILL KEEP YOU UPDATED .

Very interesting
Thanks
Great looking bike

Thanks for the report! I am going to do the same (already have the transmission) so it's nice to get the details.

neato... a 750-sixy

I wish my 750 twin had a sixth gear. Some days I try to shift up to the next gear when I am in fifth gear on the expressway.:laugh:

Thanks for the info. It would be nice to have an extra gear.

thompsonmx100 wrote:

Thanks for the info. It would be nice to have an extra gear.

The 550 transmission in a 750 offers more of a close ratio gear box than an extra or overdrive gear with no modification of the front and rear sprockets. At least according to the Kawi specs. If you were to modify (reduce) your sprocket ratio to gain top speed, then it would be more of an overdrive.

Borrowed from this link:
6 speed in GPz 750 questions

koolaid_kid wrote:

Thanks, apeman. I checked the archives, someone named Mark Bell was not successful in putting a 6 speed into a 650, apparently due to the kickstarter issue.

I did check the gear ratios, they are as follows:
550
1st 2.57
2nd 1.78
3rd 1.38
4th 1.13
5th 0.96
6th 0.85

750
1st 2.33
2nd 1.63
3rd 1.27
4th 1.04
5th 0.88

It has a lower first gear, kind of mixed in the middle gears, and a slightly higher 6th gear. The overall spread is wider, but geared to the lesser power of a 550.
Since the bike will primarily a canyon carver, this is ideal for me. When chain replacement time comes, I will probably play with the sprocket ratios a bit to make it more ideal for the added power of a 750.

first is so low that you could end up (with stock gearing) a first gear that is really not so useful... when I do my swap I am going to gear up the sprockets a bit to keep first usable (it would be nice to have easy wheelies though)

im runing a 14 in front and a 33 in the rear.

bountyhunter wrote:

I wish my 750 twin had a sixth gear. Some days I try to shift up to the next gear when I am in fifth gear on the expressway.:laugh:

Same here. Wish this was doable for our model.