The elusive KZ550 transmission into a KZ650/750 tr

Ilja wrote:

Well, I got a KZ650 with a zephyr 750 engine.. finished buidling and modifying it about 3 months ago.

That is a very nice 650 there Ilja.

A few things about the 550>750 six speed swap.

Need to use an offset sprocket or just prefer the nut type lock?
Use the Shaft drive six speed trans (or at least the output shaft), the splines for the shaft coupler are the same as the sprocket splines.
I tried to install the gears off the six speed onto the GPz trans also, but the splines were different.

Kool-Aid kid ran into other problems and got distracted with other projects, he just got started on his GPz again.

I almost got distracted with a Turbo motor and a spare Turbo frame, but I'm back on track with my 80 750E hot rod project

Bummer, no more cheap shaft drive six speed 550 trans after people read this

Steell,

I believe it was Mark Wing who tried this swap in a kickstart engine. Everything worked when it was loosely bolted together, but he had problems when it was all torqued down. I think it wouldn't go into 6th, if memory serves me.

That makes me think the tolerances must be pretty close. Having done this swap, do you think something could be machined a bit to make this work?

thanks for the shafty tip!

steell wrote:

A few things about the 550>750 six speed swap.

Need to use an offset sprocket or just prefer the nut type lock?
Use the Shaft drive six speed trans (or at least the output shaft), the splines for the shaft coupler are the same as the sprocket splines.
I tried to install the gears off the six speed onto the GPz trans also, but the splines were different.

Kool-Aid kid ran into other problems and got distracted with other projects, he just got started on his GPz again.

I almost got distracted with a Turbo motor and a spare Turbo frame, but I'm back on track with my 80 750E hot rod project

Bummer, no more cheap shaft drive six speed 550 trans after people read this

Thank you so much!! I have a shaft kz550 engine lying around in the shed. I didn't think it would fit so I bought a normal Kz550 trans... But with that one I will have the offset problem with the front sprocket because of my zephyr engine..

I'm going to do the trans swap after this season as I just finished my bike and I need it for transport right now. (100km a day :side: ) But I can't wait to do it! Maybe I'll do it sooner, but I'm afraid I will open the Can-o-worms.. :silly:

Thanks again for the information!

When I did mine I didn't have a problem with sprocket offset, but that said it shouldn't be too difficult to sort that out.

Incidently the 2000-02 ZX6R uses a front sprocket with an offset of about 7mm but... its only available in 15 tooth and its not dished so it might be too thick for the 550 fixing method.
I'm currently using one of these on my Turbo to give me the offset I require for my VFR rear swingarm.
It might be worth finding a friendly dealer who can lend you one to quickly check.


Oh and if its any help you can find sprockets from all sorts of bikes can fit. I found that the Suzuki Hyabusa rear sprocket is an identical fit to my Zephyr rear wheel for instance and was using one when I switched to the Turbo engine.
The front sprocket gearbox splines are the same for virtually all Kwacks up to 750cc its just the fitting method that seems to vary.


That bike of yours looks very sweet llja

Ok guys, im am planning on doing the six speed conversion on my kz650 zephyr the next couple of days/ weeks.

I have a complete engine of a kz550 shaft version and the trans of a normal kz550 for parts.

Disassembled the kz550 'shaft' engine today and found out that it won't fit. At least the output shaft won't. It's waaay shorter than a normal output shaft. I don't think it would even stick out of the normal transmission cover.. :dry:

So the only way i'm going to have succes doing this mod is to use the normal trans with the 'wacky washer fitting method.'

The problem is my chain alignment. The front sprocket on a zephyr 750 engine is placed about 10mm more outward then the kz550/650 front sprocket. I need this offset because i'm running a 160 rear tire.

So I would need an offset sprocket with the washer fitting method to make it work. Does anyone know where I can get these?

I was mistaken about the shaft drive trans working, it seems someone swapped some parts between the boxes that contained the two transmissions, leading to my confusion :blush:

Think maybe you could use a snap ring to hold the sprocket on? That would enable the use of an offset sprocket on the 550 shaft I would think.

Yeah, I think a circlip will be fine. I can probably even make the washer fit.

I will need 13mm of offset. Right now I have a (new)525 chain as the zephyr engine and my rear cbr wheel stock have 525 sprockets and chains... That's a pity because all offset sprockets are 530... O well... I'll just machine 1.5mm of the sprocket so it becomes 525... When my chain and rear sprocket wear out i'll go 530.

It would seem to me that offset sprockets wear quicker, (and also the shaft) because they want to pivot as the chain pulls out of the middle....but not shure.
The engine will also be turbocharged, so hope it will hold..

relocating the neutral safety switch plate on drum will allow 750 trans cover to be used. All you have to do is take plate off end of drum move taller pin to the neutral safety switch location in relation to 750 trans cover. :laugh:

Planing on doing this to my kz650 but was wondering if I can keep the primary from the 650 on the 550 trans

Nice write up guys! Im looking at a 83 GPz750 motor to put into my Z650, there is one locally but the transmission is making a noise so instead of buying new parts to fix it i'd be better off doing this, especially as i plan to go 810cc.

So, just to recap;
1/The KZ550, Zephyr 550 (ZR550) & ZX600 (what year for us europeans?, we called them ZX6's) all have a 6 speed tranny & they will fit.
2/Do the gear selectors need to be moved over too? (&what else)
3/The GPz case can be used if the neutral switch plate is repositioned?
4/I'm going to need an offset front sprocket anyway as i'll be running a wider rear rim but does this swap mean that i'll need more offset?
5/ Any complications in refitting the GPz clutch?

Is there anything more an pure amateur needs to know? like this>

Yeah, I think a circlip will be fine. I can probably even make the washer fit

If the engine is out, tilted so you're looking at the bottom of the transmission & the oil pan removed is this swap possible?