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need float hight #'s having problem with 81 750ltd
- cott10r
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2012 kawasaki concours 14
2014 suzuki gsxr 1000
2014 honda crf 250L
1983 kawasaki gpz 550
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- bountyhunter
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Anyway, I think your bike has Mikuni BS-38's and the correct fuel level for those is 4.5 - 6.5mm below the lower edge of the carburetor body (just above the bowl). You measure it using the clear tube method and adjust by bending the tang on the middle of the float.
1979 KZ-750 Twin
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- Patton
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One common cause for fuel overflow is where the float needle/seat interface isn't correctly seating, due to crud or grit, or worn parts, or possibly a damaged or sticking float, or upside-down assembly of float, or other mis-assembly.
Another cause, as bountyhunter suggested, is a too high float level setting.
And here's yet another possible cause.
Some carb overflow circuits include a small brass tube inside which sticks up from the bottom of the floatbowl.
The tube has a hole through its centerline whereby fuel rising high enough is allowed to escape through the tube and flow through an outlet nipple located on exterior bottom of bowl. Typically, a rubber hose attached to the nipple directs escaping fuel over the swingarm to drip out underneath the bike.
A possible source of leaking fuel is sometimes a crack in the tube or a break where the tube connects to the floatbowl floor. The crack may be small and difficult to detect. But it's easy enough to test integrity of the tube with the floatbowl removed and in hand. Just fill the bowl with fuel (or common rubbing alcohol for a more pleasant odor) almost to top of the tube, and see if there's any leakage from the nipple. Not supposed to be any leakage. But will leak if the tube is cracked.
Just something to check out, especially where satisfied that the float needle/seat interface is clean and correctly seating and that the float level is set to specs, and parts correctly assembled.
Good Luck!
1973 Z1
KZ900 LTD
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- cott10r
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Hmmm.... I would think if the fuel level was high enough to drain gas out the overflow constantly, the bike would run like crap. Mine wouldn't run right with one float set about 1mm to rich for fuel level.
Anyway, I think your bike has Mikuni BS-38's and the correct fuel level for those is 4.5 - 6.5mm below the lower edge of the carburetor body (just above the bowl). You measure it using the clear tube method and adjust by bending the tang on the middle of the float.
ok, what is the clear tube method
2012 kawasaki concours 14
2014 suzuki gsxr 1000
2014 honda crf 250L
1983 kawasaki gpz 550
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- OKC_Kent
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Oklahoma City, OK
78 KZ650 B2 82,000+ miles
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- OKC_Kent
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Oklahoma City, OK
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- Patton
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Typically, the drain screw is side-located on lower part of float bowl, and overflow nipple is from bottom of float bowl.
Am uncertain, but thinking some carbs have a combo drain/overflow nipple which may be used for the clear tube test.
Good Luck!
1973 Z1
KZ900 LTD
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- bountyhunter
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1979 KZ-750 Twin
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- cott10r
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Where carb has both a drain screw and a separate overflow nipple, be sure to use the drain screw hole when checking the fuel level.
Typically, the drain screw is side-located on lower part of float bowl, and overflow nipple is from bottom of float bowl.
Am uncertain, but thinking some carbs have a combo drain/overflow nipple which may be used for the clear tube test.
Good Luck!
man you guys are awsome, mine does have the brass colored rod that runs from the bottom of the float bowl up so im thinking that i will want to use the drain screw hole right? i went ahead and ordered a float needle just in case. my next step is to find some tubing, im hoping some of my r/c airplane stuff will work, iv got all kinds of fuel line tubing & what not. its weird to, this thing didnt drip right at 1st when i flipped the float and installed the needle right, it gradually got worse and worse. im confused to where the gas is coming from, because the pet-cock is working but it keeps filling my little cup i have under it. im wondering if the float needle isnt shot from the float being upside down and the float needle crammed into the seat when the float bowl was installed
2012 kawasaki concours 14
2014 suzuki gsxr 1000
2014 honda crf 250L
1983 kawasaki gpz 550
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- Kawickrice
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73 Kawasaki Z1
07 HD CVO Ultra Classic
82 Suzuki GS 1100
74 Yamaha RD 350 (My two stroke toy)
77 Kawasaki KZ 650B-1 (My putt around bike)
80 Indian Moped (My American Iron)
1
Long Gone
75 Suzuki GT550
74 GT 380
79 RD 400 Daytona Special
72 Honda CL 175
74 Honda QA 50
Tampa FL
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- Patton
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...ordered a float needle just in case. my next step is to find some tubing...didnt drip right at 1st when i flipped the float and installed the needle right, it gradually got worse and worse. im confused to where the gas is coming from, because the pet-cock is working but it keeps filling my little cup i have under it. im wondering if the float needle isnt shot from the float being upside down and the float needle crammed into the seat when the float bowl was installed
Thinking probably need to stop constant fuel dripping from #1 carb before doing the clear tube test or any float level adjustment.
Not strongly suspecting damage to float needle tip due to upside down float. Thinking more likely the float adjustment tang might have bent out of position, but just guessing.
If not already done, would fit an in-line fuel filter to help avoid future crud/grit in the float needle/seat interface.
Exactly where is the little cup located? Is it sitting on the floor underneath the bike catching fuel dripping from the overflow tube, or sitting under the petcock or under the carb floatbowl or somewhere else?
Perhaps a fuel line connection is leaking, or leaking fuel pipe (tee-joint fitting) between inner carbs, or fuel joint between #1/2 or #3/4 carbs, or crack in fuel line? Or maybe the bowl gasket is leaking as suggested by Kawickrice.
Good Luck!
1973 Z1
KZ900 LTD
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- cott10r
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2012 kawasaki concours 14
2014 suzuki gsxr 1000
2014 honda crf 250L
1983 kawasaki gpz 550
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