I have a set of Mikuni's on my KZ750, well i had them rebuilt by a reputable shop because I know almost nothing about motorcycle carbs.

Well here is my problem, if I am not moving or if the engine speed is really low, one of the carbs starts to just freely flow fuel right out the bowl vent, almost as if I have a hose directly from the tank to the ground. It runs fine and I don't feel any adverse effects from this, but throwing fuel away is agitating me. I need to get this fixed asap, but have no idea what it could be.

 

Needle and seat could need replacement, or maybe its fine and just not installed right. Float tab could be slightly bent causing the floats to hang up on the sides of the bowl. Or the float level could just be way out of wack. Thats about it.

 

I would be willing to be that your float is toast in the carb... its like a float in a toilet and regulates flow... it being bad would mean that it is staying submerged and allowing fuel to be drawn/flow into the bowl. I am almost positive that is your issue. if there is no rebuild for that part you'll need a new carb unit or at the very least a parts carb to dismantle. the floats are only good for so many years before they need replacement. are those cv carbs or guilotine carbs>?

 

I saw the carb in the other thread, cv's...

 

the wierd thing is thaqt it does not constantly do this, only when there is no load on the carb.

 

Yep thats true, if a float doesn't float, then its not a float anymore. I guess. That could be it. I may have a set of those carbs here if you can't get it sorted.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DirtySol &raquo;</TD></TR><TR><TD CLASS="quote">the wierd thing is thaqt it does not constantly do this, only when there is no load on the carb.</TD></TR></TABLE>

Thats not wierd at all... under load, your bike is using the fuel. Sitting still there is excess fuel being fed

 

well, I have it apart right now and the floats are fine, both within 2 ghrams of each other

 

Make sure they float. Put them in a cup of gas and see. They could have just emptied out if they are indeed leaking.

When this leaky carb happens to me I'll give the float bowl a good whack with a screw driver handle before I tear anything down. Sometimes it will fix it, and if thats the case you know right off the bat its the float hanging up on the bowl.

 

figured it out guys, thanks for everybody helping me out.....not very often I need it.

Found the float (dual style) to be bent and hanging up on the outside of the bowl. bout to re-install it back on the bike.

I put about 10psi of shop air to it and nothing was getting by. Hopefully this does the trick.

The needle did have a small wear ring but nothing that would hinder action. I think I was just inspecting everything too hard. Better to be safe than sorry.

 

So much for being a reputable shop

 

well, I lied about finding the fix......I put it on and no change.

I took it back apart and found that one side of the dual float has a crack and does not in fact float. I am going to try something to possibly seal the crack until I can find a new float. Any ideas?

 

gonna attempt to solder it

 

That's what I would suggest. Assuming it's a metal float. And afterwards, dunk it into some water to see if it is air tight. I've got a mid-sixties suzuki, and I've got a series of carburetor woes myself.

 

HAH!

i fixed it!

Solder did the trick and now my float actually floats!

 

39mm Mikuni carbs FTMFW!

 

More like 29mm CR specials FTW... I think stockers are 32 CV's or something.

 

just measured them, 39mm at the butterfly

 

Its not 39 all the way through. They are 32 or 34 CV's IIRC. 39's would be like for a kz1250 drag bike!

 

Good on you for doing your own work

Thats part of the two wheeled lifestyle
NOW GET SOME REAL CARBS DAMN IT!

 

I just noticed from the pic in the other thread its a twin. I ASSumed it was a four since thats all I'm familiar with. So you're likely right that the carbs are 39's or something like that. Still, if you ever want to upgrade your carbs drop me a PM.

 

they are Mikuni RS34 carbs

here are the specs

Kawasaki KZ 750 Mikuni RS34 115 17.5 P4 9DZH1 Pilot screw 1/4-1/2 turn out

I need to find a replacement float if anybody can help me out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MSchu &raquo;</TD></TR><TR><TD CLASS="quote">
NOW GET SOME REAL CARBS DAMN IT! </TD></TR></TABLE>

what is wrong with Mikuni's?

I have used them on side draft setups on a couple of my cars for years

 

Who said anything was wrong with mickies?

 

you did