TOPIC:

Bought a 1977 KZ650 about two months ago w/ a carb leak. If you're sitting on the bike, from left to right, the third carb in was leaking from the overflow nipple. I pulled all the carbs and cleaned them. After that, carb 3 stopped leaking, but the one next to it, carb 4 started to leak from the overflow nipple. Pulled them again. Cleaned them, put them back on the bike, then carb 2 started to leak! Pulled them AGAIN: bought steel wool, checked the float needles (look good, w/ sharp points), checked the tang on the float, bought a clear float level tool, adjusted floats where necessary, cleaned other jets and what not. I put the carbs on a "test" stand w/ fuel in a bottle feeding the carbs, left it for two days. No leaks! Thought, "Well, heck! I fixed it." Put carbs back on bike, filled the gas tank, now carb 1 is overflowing from the overflow nipple! It's like musical chairs over here.... Checked the float level on carb 1 and the fuel is actually BELOW where it should be. What gives?? Am i missing something?

Might just sell this and get a fuel injected bike, haha!

M

Here is a link to a carb rebuild tutorial that may help you...members.dslextreme.com/users/bikecliff/i.../vm_carb_rebuild.pdf

Short cuts are long cuts when it comes to carbs. Also, you might want to look inside the tank for rust sediment.

Looks like your float neele valve did not seated right, it´s time for some new

Mikuni
www.motorradbay.de/z650-kyv-03r25_5-floa...d9c3981d8279995eaf91


Keihin with a rubber cone
www.motorradbay.de/z650-kyv-03r25_5-floa...d9c3981d8279995eaf91

Is the bike on the center stand or side stand when #1 leaks? Ed

It's on the center stand. I might just need to get new float needle valves.

M

Don't buy new ones. Get some Brasso and use a q tip dipped in brasso to polish the seat. Use some 3000 grit wet / dry sandpaper to clean and polish the valve tip. In the 40 years of working on bikes I have never had to buy new carb valves and seats. Besides the aftermarket replacements are still not as good as the OEM ones currently in the carbs.

Baldy is right. The replacements are not as good as the originals. Polish them and reuse them. As long as the spring end on the seat is working properly, they will polish up fine. I use a dremel and cordless drill to spin / polish parts all the time. I don't have brasso.. (not since the US army), but use a decent chrome polish creme.

Also make sure the petcock is shutting off like it should. Measuring the float height with the carbs inverted will get you in the ballpark. Wet check dials it in.

A little extra fuel line and you do not need a seperate fuel container. I unhook it at the filter, and then reconnect it all easily when I'm done.


Make sure it's level with your johnson.

I had a carb overflow leak on an old Z1 I bought. Took me 3 weeks to chase it down. Turns out the overflow pipe inside the bowl was corroded right at the bottom, just where it’s pressed into the bottom of the bowl. Gas was getting into the overflow pipe there and exiting the nipple, looking like the bowl was overfilled. Just something you might want to check.

Zeerx wrote: I had a carb overflow leak on an old Z1 I bought. Took me 3 weeks to chase it down. Turns out the overflow pipe inside the bowl was corroded right at the bottom, just where it’s pressed into the bottom of the bowl. Gas was getting into the overflow pipe there and exiting the nipple, looking like the bowl was overfilled. Just something you might want to check.

^That^
Overflow pipes also have a tendency to develop lengthwise hairline cracks that will weep fuel continuously.

Good Ridin'
slmjim & Z1BEBE