adjusting floats and float bowel part

1980 KZ750E. Is there an easier way of adjusting the floats that using the clear tubing? it seems to take forever and I never get them right, it's too much or too little. And I found one of my float bowel covers has the brass tube broken so fuel pores out even when the screw is closed. Any suggestions what I can do to fix both these problems? always appreciated.

There really isn't any better method than using the clear tubing. You can set them dry by turning them upside down (make sure they are level) and set the floats so that they measure 22mm +/- 2 mm (IIRC, been awhile since I bothered with the dry method) above the bowl gasket. This really only gets you close though and you're bound to have to fine tune them from there, hence the reason I haven't bothered dry setting them on the last 3 racks of carbs I've done...

The clear tube method gets you dead balls on for your float height, and is really the only way to get something that critical correct.

azr wrote:

...found one of my float bowel covers has the brass tube broken so fuel pores out even when the screw is closed. Any suggestions what I can do to fix both these problems? always appreciated.

Probably referring to the overflow tube which is supposed to allow excess fuel to escape when the fuel level reaches abnormal height for whatever reason, and which is usually well above optimal fuel level. A typical reason for this happening is when the float valve fails for whatever reason to stop the fuel flowing into the float bowl.

A cracked overflow tube may sometimes be satisfactorily repaired.

How is it broken? Cracked? Bent? Tip broken off? Entire tube missing?

fuel pores out -- is fuel flowing from the overflow nipple on bottom of float bowl? Or escaping from somewhere else?

If available, a pic may help repair diagnosis. And sometimes it's more feasible to just replace the float bowl.

See diagram added below to help explain. The drain screw isn't shown on this diagram.

Good Fortune!

[Click on image for better view.]

unfortunately the tube is broken clean off. Fuel is flowing out the nipple. Any ideas where I can track down a new float bowl?

I have the same 1980 750/4 so probably the same carbs - keihin cv34 and I know exactly what you mean. It took me 3 hours yesterday and I'm still not sure if I got it right. However, clear tube method is really the only way.

The Keihins are a bit different from Mikunis in that when the drain screw is opened the gas comes out the overflow. With the brass overflow tube broken clean away I'd say try ebay or your local salvage yard or perhaps your kawasaki dealer. Some carb parts are still available from kawasaki but are not cheap.

In the meantime - and I'm just thinking out loud here - but if the float valve is working and if the level is in the ballpark what would happen if you connected an short tube from the overflow of the dud bowl to the overflow of the one next to it and opened the drain screw on that one ? The levels should equalise. Remember , the drain screw empties into the overflow. I'm not suggesting this as a possible permanent fix as you would have no overflow on 2 carbs . Just very temporary until you get a good bowl.

What type of carbs? I think I've got a bowl or two from some vm series with accelerator pumps laying around the garage.

The carb rack is stock for a 1980 KZ750E. I'll try and find a number on them tonight. I found a new price...$1159, ha,ha,ha.. what does that make your one bowl worth???????? I'll try and post tonight/tomorrow on the carb identification. Interesting idea with connecting the drains but I'm not riding the bike right now so I have lots of time to hunt down another bowl. I was glad I figured this out though, I kept getting fuel in my airbox, and lots of it, when I was trying to get the old girl running. She's been sitting for 3 yrs with the PO. Dipped and cleaned the carbs but never noticed the tube missing, lol.

Just in case... A lot of places have parts diagrams w prices for everything, but they do not have nor can they get a lot of that stuff. I'm going to guess that you have some type CV carbureters.

You say the tube is broken clean off, so maybe you can hold it in place then pack some JBWeld or some other fuel-proof stuff around it at the base. Perhaps you could slide a piece of straight wire thru the bowl & tube to keep it lined up, and twising the wire to make sure it doesn't get welded in place, just in case the epoxy enters the tube's orifice. Just an idea.

For speeding up the process of setting the floats, it saves time to reinstall the bowls w only 1 or 2 screws. When I did mine, I made a simple carb stand & rigged up a funnel & tubing hung from a coathanger as a fuel supply. To adjust the tang, I rigged up a float support so that the float bracket wouldn't get buggered, and instead of bending the tang, I would flex it a number of times.
Flex,flex,flex,flex,flex, install float, install bowl, add fuel, check. etc, etc. It took me a couple of hours, but I was able to get all four spot on (I didn't trust the +/- 1mm stuff).

azr wrote:

...kept getting fuel in my airbox, and lots of it....

Fuel may have also found its way into the crankcase.

Would sniff-test crankcase oil and examine its physical condition. If any doubt about fuel contamination, would change oil and filter.

Good Fortune!

I really like JMKZHI's idea when he said

"You say the tube is broken clean off, so maybe you can hold it in place then pack some JBWeld or some other fuel-proof stuff around it at the basePerhaps you could slide a piece of straight wire thru the bowl & tube to keep it lined up, and twising the wire to make sure it doesn't get welded in place, just in case the epoxy enters the tube's orifice. Just an idea."

You can get thin brass tubing in 1 or 2 foot lenghts at most hobby shops and use the advice of holding in place with a wire while the JB Weld sets. Years ago I had a crack in an overflow tube and I slipped a piece over the existing overflow tube and soldered it at the bottom. If you use JB Weld just make sure you leave it 24 hours to cure.


Stock carbs on the 1980 KZ750/4 were Keiin CV34s. The #1 carb will have Keihin stamped on it just above the choke lever. The K will look sorta like a star.