TOPIC:

harm wrote:

but 6th gear would not engage once it was torqued down.
It sounds like a clearance issue that maybe easy to fix for someone willing to take the time with it.

You know, when I read mark Wing's saying the gears would all engage till the cases were torqued down, but not after, the first thing that occurred to me was it had to be pretty close, and maybe a little "massaging" would work, but Mark is really knowledgable and super-meticulous. I have to think if it was that simple, he would've solved it. maybe he'll chime in on it.

My @#$%!!! KZ650 is a '79 model, and has never gone 400 miles without leaving me beside the road; the kickstarter is considered "essential equipment" to me, if only as a way to vent my rage and frustration until AAA shows up. Hopefully, I'll get that figured out at some point, though, and when I do, I'd be willing to give up my kickstarter in order to get a 6-speed.

Imagine, though, that fitting a KZ550 6-speed into a kickstart KZ650 ended up being simply a matter of a little machining on the gearset. Someone with the equipment and skills could make a little jingle-jangle picking up KZ550 gearsets on ebay, doing the machining, and selling kits to KZ650 owners who want to have their kickstarter and a 6-speed, too.

Of course, that would be waaayyyyy too easy.

I don't know if it would be a simple matter, but anything is possible.

I would imagine that you would need to obtain a full kick start shaft with the spring and all the goodies, then remove the gear at the end and fit the shaft with an appropriate gear matching the kz 550 trans gear it would mate with. Not impossible, but if you are going to climb into the bottom end of your motor I assume you will be addressing the problems that make your bike unreliable.

Once those problems are addressed there is no reason to keep the kicker. I too once refused to build an engine without the kicker, but in the last year I put 5k on my bike and used the kicker exactly 0 times. If you are using an excited field stator then the kicker won't even help you if the battery dies ( I know from experience).

Well, after two and a half years of owning that @#$%!!! KZ650, my right leg looks like Arnold Schwarzennager's, and my left leg looks like That Olson twin with aneorexia's.

But you're right, kickstarting very seldom works, but it does save me from lighting that @#$%!!! KZ650 on fire (so far).

Hi Guys. sorry I haven't been on for a while but saw the PM I got so thought I'd drop by and see what's happening.

The swap itself is easy.
I used the trans out of a GPz550 and you need to install the gears, the shifter drum, the transmission cover and shift forks too. Basically the ENTIRE transmission.
The transmission cover was needed simply to retain the neutral light as on the 550 shift drum the switch activator bit is in the wrong place relative to the position on the 650/750 cover.
In addtiton once it was all running I found that 1st gear was too low really so a simple change to a larger front sprocket sorted this. However the 550, dunno about zx600 output shafts do not use a simple nut to hold the sprocket on and use a funny washer and bolt setup instead, this seemed fine too though although I'd have preferred the Nut style of fixing
I kept my stock 750 clutch too as it slots nicely onto the 550 shaft but I think I had to play around with a few washers to get the right clearance between clutch and casing.
Overall it was reliable and I had no problems at all transmission wise. I was running GPz750 cams which complemented the gears perfectly as they allowed the engine to rev a lot quicker albeit with a touch less bottom end, hence the better use of a 6 speed box.

I dont think there is any reason why a kicker cant be used with it, I even thought about converting mine to have one at the time. But I never got around to it so never found out if it could be done.

Some pics I found....


This is under the transmission cover showing the 550 drum with neutral indicator on its end.


750 and 550 trans covers. The one on the right is a 550 one and if you look you can see the holes on both where the neutral switch screws into, they are in different locations on each. Also not apparent in the pic is that while both have the pretty much the same bolt hole arrangement, the top right bolt and dowel are slightly out and there is a small gap at the very top when the 550 one is fitted to the 750 cases. I thought it might lead to an oil leak so I simply cut myself a wider gasket using some gasket paper and used that to seal the gap. worked a treat and no leaks.


550 drum and shift forks. Think the gear lever mech is 550 too.

Any questions???

Have fun and Its definitely a project I'd do again if I was tuning a NA 650 or 750 motor.

Oh and while I'm not the king of cheap, I picked up 2 entire 550 engines for about $10 which is how I got to attempt it in the first place. Other than gaskets It didn't cost me much more

That is definitely king-of-cheap-worthy. I thinkSteell would be suitably impressed.

Thanks for all the info guys.
Got this one saved.

Rob,think there'sany way you can convince Steell toweigh in on this?

Awesome!!

I am glad we finally have someone who has completeded this mod and run it on the streets.

Mine will be done by the end of winter, but I am glad to hear someone had gotten it done and come back to post about it.

How large did you go with the front sprocket?

Are the sprockets for the 550 output shaft difficult to find?

Is the chain still running true or does the new output shaft move the sprocket slightly from the standard 650 position?

Great info!

No probs with chain at all. Can't remember which sprocket I was using. A 550 one of course fits but it depends on what type of chain you are running. bear in mind that the zx600 and some others used the wacky washer fitting, so you should have no trouble finding a size to suit your riding style.

GPzephyr, you used the GPz750 motor to do the swap, that's why you had to change the trans cover, all but the GPz750 cover have the neutral light switch in the same place and interchange, even the 750 twin cover will work

KZ650 kicker will work on the KZ750 motor, but not with the 6 speed conversion, just not enough room for everything. I have a KZ750 four motor with kickstart.

Assuming you have it up and running, where did you get the offset sprocket needed for the GPz750, that fits the 550 output shaft?
The 550 uses that flat metal lock that has two bolts holding it to the sprocket, and makes things a little difficult when attempting to combine two sprockets to make one offset sprocket. I have thought about using a snap ring of the proper size, but I haven't got a rountoit yet, so I don't know if it would work.

Wait a minute, maybe you put a GPz750 motor in a Zephyr (I didn't read the whole thread)? That would explain your lack of problems finding a sprocket, it wouldn't need one, just the 83-85 GPz750 needs the offset sprocket (running stock wheels).


I did try and put the gears from the six speed on the 750 shaft so I could keep the threaded end on the output, but the 750 shaft is larger and the gears won't fit.

Oh and while I'm not the king of cheap, I picked up 2 entire 550 engines for about $10 which is how I got to attempt it in the first place. Other than gaskets It didn't cost me much more

I'm envious

Hey Steell, a couple of questions.

Awhile back, you put a link up in a thread about a 6 speed conversion you were doing that you said had more info, but the link is dead. Was that a detailed how-to for this swap, and if it was, do you have access to that thread?

Also (correct me if I'm wrong) in the thread in question, I'm pretty sure you were doing the swap in a GPZ750. Have you done it in a KZ650 as well?

Also, when Mark Wing tried it in his kickstart KZ650, I'm pretty sure he said he lightly bolted the cases together and all the gears worked, but it wouldn't go into 6th when he torqued the cases down. With the tolerances that close, do you think it might be possible to gain enough additional clearance through some machine work, or is it just a case of "so close, but so far away?"