A new member with a KZ400...

Nerdy wrote:

loudhvx wrote: Great little 400! I've had that same combo... gpz550 and Kz400, but the 400 is long gone. I really miss it for knocking around the city.

I'm planning to hold on to both for now.

If I may ask, were you loudgpz on another forum?

No, but my website had "loudgpz" as part of the URL. Now with a different server, it no longer does.

The links to the new site are in my signature. There is a site specifically for the Tk22 carbs found on the 81 gpz550. Also the link about the valve train might come in handy when you start to work on the 550. There are also several online manuals for the Kz550 bikes... links found on my main page.

Nerdy wrote:

mark in Portugal wrote: I'll add to the cacophony; nice looking bike.

Thank you!

Don't worry too much about those exhaust pipes; they aren't original.

Respectfully I believe they are. There is no evidence of anyone changing anything and they look exactly like the ones in this '79 KZ400 B2 pic (from kz400.com):

Sorry, I withdraw my ignorant comment!
I had a '77.
and a '75
And briefly, a '79 I took the crank and rods from to resurrect my '77 [some trickery was required]
And a '76 for parts for the '77.

mark in Portugal wrote: Sorry, I withdraw my ignorant comment!
I had a '77.
and a '75
And briefly, a '79 I took the crank and rods from to resurrect my '77 [some trickery was required]
And a '76 for parts for the '77.

No problem!

Can you describe the trickery?

loudhvx wrote: No, but my website had "loudgpz" as part of the URL. Now with a different server, it no longer does.

The links to the new site are in my signature. There is a site specifically for the Tk22 carbs found on the 81 gpz550. Also the link about the valve train might come in handy when you start to work on the 550. There are also several online manuals for the Kz550 bikes... links found on my main page.

Thank you for the clarification. I'll definitely check out the links: I started to rebuild a spare set of carbs for the 550 but got distracted by the 400.

You wouldn't happen to have a source for rear master cylinders, would you? I found one on Amazon that should fit with minor fiddling and fabrication but any info would be helpful. TIA!

Nerdy wrote: ...
You wouldn't happen to have a source for rear master cylinders, would you? I found one on Amazon that should fit with minor fiddling and fabrication but any info would be helpful. TIA!

I never found an exact replacement or even a rebuild kit. But with, like you said, some fiddling and fab work, I was able to use a Ninja 250 rear master. It somehow feels better than either of my two other stock rears, even though the piston is the exact same size.

It requires two spacers and adapting a long, threaded push-rod.

Nerdy wrote:

mark in Portugal wrote: I had a '77.
and a '75
And briefly, a '79 I took the crank and rods from to resurrect my '77 [some trickery was required]
And a '76 for parts for the '77.

No problem!

Can you describe the trickery?

Sure;
I imported my '77 KZ400 into India in the early '80s; this was a very big deal, almost imposable to do because of the strict laws against imports at the time.
So the bike was very special; the equivalent of having a Ferrari in the US. But I let something into my oil galley [another whole story] which eventually found a rod bearing.
So on a brief return to the US, I needed to buy a donor bike; at that moment and place, the only thing that came up was a '79 model..
I'd brought the damaged crank with me, and it dropped into the '79 case; but the conrod bearings on the '79 are smaller. The same center to center length though, and the small ends are the same.
The '79 also has a larger end where the stator fits.
So, I took the '79 crank and rods, and I cut the stator end off the old crank too, and took it all in my suitcase back to India.
My machinist had no problem cutting the '79 stator end down to fit the '77, using the sample I'd brought.
Put it all back together and rode it for about 20 years.

Then the balancer chain sprocket on the crank got stripped.
I had a spare balancer chain in my parts hoard; but how to repair the crank?
First, I put my spare engine in the bike, which I kept in a sturdy wooden box for some years waiting for just such an emergency.
In my parts hoard were several old balancer weights and sprockets; I took it all back to the same machinist [we were pals by then] and had him mount the crank on his lathe and cut away the stripped sprocket, and then cut a shallow groove where it had been.
Then he mounted the spare sprocket, and cut the inside to fit the grove on the crank.
Then I cut the sprocket in half with my new thin angle grinder cutting wheel [through the top of two teeth, not where the chain will ride], and he welded the two halves to the crank with my little DC welder. He was better than me at welding back then.
Mounted on the lathe again, he cut the welds smooth, and the crank measured true.
I just needed a new chain guide; I forget which. anyway, I never went back to India after that, and never put that motor back together.
I sold the bike by remote control to a happy local fellow, and sold the repaired crank and my golden hoard of new + used parts to someone else who [amazingly] also had a KZ400 in India and had the same problem. He traveled hundreds of miles across the country to get those parts in person.
And for some odd reason, I have a picture of it;



Now, who wants to read the epic of the 1977 Z400 monoshock conversion?

Mark, that is a great story. I have a coworker from India. and he has all sorts of stories like that... going to outrageous lengths to accomplish what we take for granted in the U.S.

mark in Portugal wrote:
Sure;
I imported my '77 KZ400 into India in the early '80s; this was a very big deal, almost imposable to do because of the strict laws against imports at the time. ...

Wow, that is some trickery. Thanks for sharing!

Now, who wants to read the epic of the 1977 Z400 monoshock conversion?

*raises hand*

mark in Portugal wrote: Now, who wants to read the epic of the 1977 Z400 monoshock conversion?

Yes, please!

loudhvx wrote: I never found an exact replacement or even a rebuild kit. But with, like you said, some fiddling and fab work, I was able to use a Ninja 250 rear master. It somehow feels better than either of my two other stock rears, even though the piston is the exact same size.

It requires two spacers and adapting a long, threaded push-rod.

That is fantastic; thank you very much! The Amazon item would have required the longer threaded rod and the mounting holes were 50mm center-center (so it would have fit, mostly) but I can't speak to the quality. Brakes are fairly important so I'll be more comfortable with a Kawasaki part vs a random part.

As I understand it Kawasaki used that rear master on only the 1981 GPz550, which is why there are no rebuild kits available. Not sure if that's 100% true but the end result is the same so it's probably not 100% important.

Nerdy wrote: ...
As I understand it Kawasaki used that rear master on only the 1981 GPz550, which is why there are no rebuild kits available. Not sure if that's 100% true but the end result is the same so it's probably not 100% important.

It's the only U.S. Kz550 that uses that master. I think there may be one year where the same piston was used on a Kz1000, so they might have used the same rebuild kit, but either way, in 20 years of searching, I have never found a kit. Up until 5 years ago or so, I've just been cleaning used ones I could find from ebay, reusing the same seals etc., but the pitting in the body is bad enough now that even a rebuild kit probably wouldn't help. They end up leaking.

While the insides of the Ninja masters, I found, look perfectly new and polished. I only paid 10 bucks or so from a salvage company.

I had a 1981 gpz550 as well;
Mt dad was a motorcycle race rider in the '50s [standards were low at the time, he was the first to admit].
He hadn't ridden a bike in 10 years or so, when he asked if he could borrow the GPZ to run a lot of errands in the city.
I was outside when my fat old dad got back; he locked up the front wheel and skidded to a stop.
"If I'd had this thing back in my racing days, I could have been a winner!" he claimed.

The KZ400 monoshock conversion;

As stated earlier, I'd imported the KZ into India in the early '80's where I enjoyed being a big fish in a small pond, blowing everyone off the road at the time.
I was good, but not the best rider; I just had the best bike by a huge margin. Part of this was having the money, part was the ability to obtain spare parts, and a large part was the ability to repair it. The local mechanics were simply hopeless [and I'm saying that even though some were friends of mine], and I'd been a car mechanic in the US for a while.

My exuberant riding style was only possible because I had decent suspension. Crap by today's standards of course, but much, much better than the local bikes.
After a couple of years though, I was starting to get significant rear end twist on large swing arm movements. I had to bring everything in my luggage by air, and there was always tension about getting the parts through customs in Bombay.
I bought the best shocks I could get at the time, but they would only last a couple of years.
The roads there looked flat at a casual glance, but actually they were laid by hand, and all had a rippled surface. Ambient temperature were high too. The rear shocks would just overheat I think. A 10% difference between the two and it was doin' the twist.
So, I measured and planned, then living in Holland in the summer at that time, I called White Power suspension [later changed to WP on account of their name has disturbing connotations].
After much discussion, they told me a shock for a Honda 650 Bros [which, by coincidence I came to own one of later] would do it, but they'd have to make me a custom shorter version.
It was expensive, but actually still affordable.
I took the precious unit back to India, and proceeded to brutally butcher the KZ.
I'd already removed the original airbox and changed to K+N cone filters [drilled the jets too]. I had a funky arc-welder, a little grinder, and a drill.
I welded two drilled tabs at the top of the frame where the tubes all meet. I couldn't bend tube, so I welded the swingarm braces all with straight pieces and gussets. I put the lower shock mount as close to the tire as I could, triangulated on the frame I welded to the swingarm; no clever linkages. But I had to change the plan and put the mount above the cross brace, which I never liked because it stressed the welds asymmetrically. If I could have mounted it in front of the cross brace, it would have all been in compression.
I had 3 springs with me; the softer one was good.
I can't say it was better than a new pair of good twin shocks; the KZ400 frame and front end just isn't rigid enough for the monoshock to make a difference I think. But the WP shock lasted for years and years; if the damping degraded a few percent, it didn't matter and I couldn't tell.
I cut the old shock mounts away completely a few years later, because a law change there outlawed any structural modifications and they were doing inspections.
No one ever suspected for a second that it wasn't built that way; the welds on the swingarm looked nice [my job at the time was steel fabrication], it was only if you looked under the seat you'd see those funky gussets and things.
I might have pictures in my old chemical print collection; I could only find one fuzzy photo on my computer to share with you all. The bike is on the back of a camper I built there.


One million people die every year on Indian roads they say; back when I was terrorizing the country it was probably only half a million. Still, I'm amazed and thrilled to be still alive to write about the insanity of my youth.
Today I drive a little diesel car, or a farm tractor... no more motorbikes. I do miss it, just can't afford to be injured again.