Transmission swaps

Looking to change gears in my 79 KZ1000 MK II. Found a posting dated 2-11-2003 (TwoCam)stating the "J" model trans can be swapped into the "Z" model with some modification. I'm trying to find out what those modification are.

Has any body done this?
Thanks for the help.

THR

You can buy a conversion kit to fit a gpz/j cluster to the early 900/1000 cases ( just bought mine from hoopers pitstop )that consists of a new outputshaft bearing / seal and spacer but there is still machining (lathe work) to be done for clearance on the selector drum (you retain the 900/1000 drum) and one of the gears.

You'll also need to modify the big shift fork to clear using Z cases with later tranny. IIRC, gear clearance machining is only needed using 83-84 GPZ trans, not the J. Check to be sure.

Jack wrote: You'll also need to modify the big shift fork to clear using Z cases with later tranny.

Yep that too .
Didn't go into all the details coz you get instructions with the kit.

Thanks for your reply. I wasn't able to find anything listed as "hoopers pitstop". Do they have a site? Is there a title or part number for the conversion kit?

Thanks

Bill

pitstop performance,yep he advertises here

THR wrote: Looking to change gears in my 79 KZ1000 MK II. Found a posting dated 2-11-2003 (TwoCam)stating the "J" model trans can be swapped into the "Z" model with some modification. I'm trying to find out what those modification are.

Has any body done this?
Thanks for the help.

THR

why do u want to change gears?
guys only do this mod for more strength. the added strength is only nessesary for a big block on the strip.

gear ratios are differant also i think

Mark1112 & wireman;

The ratios are different, the CSR (81) has higher gear ratios than the MKII ("Z" engine)(73-80).

The reason for the interest is because we are building a 1327 cc engine, based on a 79 KZ1000 MKII
that will be used for Bonneville. I'm looking for the highest gear ratios for 3 to 5 mile top speed runs.

THR

id call ape they can do every thing you need done.

THR wrote: Mark1112 & wireman;

The ratios are different, the CSR (81) has higher gear ratios than the MKII ("Z" engine)(73-80).

The reason for the interest is because we are building a 1327 cc engine, based on a 79 KZ1000 MKII
that will be used for Bonneville. I'm looking for the highest gear ratios for 3 to 5 mile top speed runs.

THR

Great stuff. Hope you post some pics in projects and keep us updated.

I'm doing the same but building a supercharged 1428 for tootling to the shops and back.

Here is a copy of a post i saved from Dragbike.com by BillRobinson.
This IS the guy u want to do this kind of work for you.
HE IS THE MAN.

I’m sure I have posted this info somewhere back in the archives, but here it is again. This time I’m going to save it so I can just paste it up.
The following should be done with a complete undercut job and be performed by an experienced technician for best results.
To fit the J/GPZ trans in the Z1/KZ case the mods are as follows: Input shaft: Using a J input shaft you must bore the threaded end so the 3/8” ball and the Z1 pusher fits inside. Using a GPZ shaft the threaded end must be shortened and re threaded as well as boring.
The 5th gear input needs to be turned down to clear the shift drum and the drum must also be turned because you cannot take all the material from just one of them.
The 4th – 5th fork must be clearanced on both sides to clear 3rd and 4th gear on the input shaft.
A conversion bearing, spacer and seal are also necessary.
There is also some re shimming to be done on both shafts to obtain proper neutral clearances and engagements. If this is not done correctly, it will get itself into 2nd and 5th at the same time and cause considerable damage. I’ve seen it plenty of times. Chewed up teeth and broken dogs—Very ugly!
There are two different 3rd gear sets and output shafts. The J has 21/30 T and the GPZ has 19/ 27T. They are both the same ratio, but the GPZ set uses a larger tooth pitch with less teeth. The J output shaft uses a bolt to secure the sprocket and the GPZ uses a nut and also has about 3mm. more spline. The GPZ parts are the more desirable ones. If you cannot find these parts, the gpz output shaft (13128-1048) and 3rd input (13129-1566) are still available from Kawasaki. The 3rd output is no longer available, but I make a replacement that is stronger than the stock one.
There are a few more small details, but this is the majority of what has to be done.
I cheated and only put in a billet 2nd gear for my 1200kz.
Good luck boys.
Mark