Fuel Leaking from #3 - airbox side

Hi all,

Hope everyone is well.  

Thanks to Nessism, and a bunch of helpful advice, I just completed replacing all the rubbery bits in my '83 750 Spectre's CV34's. There weren't many issues (though I did find that the pilot adjustment screws were almost all set to slightly turns; 2 1/2, 2 1/2, 2, 1 - from cylinder 1 to 4 - I've reset them all to 2 1/5). 

Everything went back together pretty well and I just hung them up levelly and put fuel to them again. No leaks from any of the fuel transfer tubes, float bowls, or drain screws. thats awesome.

However, fuel is slowly leaking directly out of the intake port/air box side on carb 3. I then tested the fuel/float levels and 1, 2, and 4 seem ok but 3 looks too high.

I am looking for any advice here, because this is my first crack at working with carbs and just I'm going on the manuals and this forum. My research says to pop off the float bowl and tweak the arm on the float to get the fuel level back in spec. Easy enough, I guess, but if there is anything I don't know that I don't know, please chime in.

Many thanks for helping me get this far.
B

One other thing... Just before I took this bike into the shop to revamp her, I had noticed that snow wouldn't melt off the #3 header. Now I'm wondering if I might know why.

 

You could also check the float support arms, float pin, & float to make sure nothing is bent. and make sure the float moves freely and isn't sticking. As for the tang adjustment, I made a simple support jig and flexed the tangs x number of times (instead of bending them) and was able to adjust the fuel level precisely  (3.0mm in my case for VM24 carburetors). A carb support stand for checking the fuel also helped speed up the process. simple homemade jig. some guys use a bench vise.

I'd check the float needle and seat in #3.  Make sure the spring loaded pin, that contacts the float tang, is free and moving smoothly.  Also, look at the rubber tip, and make sure it's not deformed.  Lastly, inspect the float seat.  I use a heavy duty industrial Q-tip, dipped in brass polish, and spun in a drill motor, to make sure the float seats are in good condition.  

Lastly, sometimes rust from the tank gets into the float needles and hold them open.  If you drop the bowl, and see evidence of brown rust, you likely have found your problem...

To me you need a carb level tool to adlust the fuel level on the float bowl. You can find them on ebay or parzilla i think.

Fox wrote:

To me you need a carb level tool to adlust the fuel level on the float bowl. You can find them on ebay or parzilla i think.

For the CV34's, all that's needed is a piece of clear tubing attached to the nipple on the bottom of the float bowl.

Like ED said, no extra's required, just a nice fitting tygon-clear or some hardware variant tube at the base of the overflow and open the Phillips screw. You'll easily find fuel level. Hopefully the Phillips drain screw has a decent oring but that's a different conversation. Also hopefully it's not stuck, have seen many that were. As far as the float needle and seat, have a glance at this info. If it's flooding out the intake, rest assured it's also going straight down the intake of affected cylinder. Here's an additional addendum of what Ness (ED) had mentioned and a bit more. He's a smart cat but i never waste my time with pedestrian toothpaste or any swivel mechanisms, just shuck and replace. Know that the Kawaski had a "thinking" 2.4 float seat whereas Suzuki used a 2.0 something. At least i can tell from a Keyster labeled replacement. But 2.0 would work just fine with a stock engine. Anyhoot, one can interchange these BS34 parts around between models noting there is a difference in the needle and seat. But ya can't easily effectually put one kawasaki needle into a suzuki seat and vice-versa, they operate within perimeters of each other. Heres a pic of a suzuki Keyster set set into an early J carb set, works just fine, A might expansive but more info is better then just someone blurting crap out. Pictures are cool. Also make sure you didn't just jam that 1.5x7mm float seat oring home, needs a little fingertip of oil to get it seated. You can buy those at any hardware store if you messed-up  

Just thought, where is your petcock vacuum routed to? If you have a funky petcock that has a leaking diaphragm it'll do exactly the same down the carb barb it's attached to. 
.

Thanks for all the info, guys.

First off, yeah, as per both the clymer and the factory manuals, I did just use some clear tube to check the fuel levels. That said, I was using one of those gravity fed auxiliary fuel tanks from Motion Pro with the petcock wide open. No vacuum. Could this be an issue though?

Second, I've rigged up a quick bench stand using some small pipe and fittings. It does make things easier.



So far, I've popped off all the bowls and checked that everything looked and felt like it was moving feely; no obvious issues. I have pulled the float pins, floats, and float valves (which are also new but from one of those rebuild kits on "the bay of E".

All the rubber is already new. Ness sold me a full set of fresh o-rings, and I think I've gone through and replaced everything.

Next step is to run out to grab a little brass polish.

Pictures below... 

Here's the full rack, 1 to 4, left to right

 
 

Here are details of carb 3 and its parts.

asphalt900 wrote:

Like ED said, no extra's required, just a nice fitting tygon-clear or some hardware variant tube at the base of the overflow and open the Phillips screw. You'll easily find fuel level. Hopefully the Phillips drain screw has a decent oring but that's a different conversation. Also hopefully it's not stuck, have seen many that were. As far as the float needle and seat, have a glance at this info. If it's flooding out the intake, rest assured it's also going straight down the intake of affected cylinder. Here's an additional addendum of what Ness (ED) had mentioned and a bit more. He's a smart cat but i never waste my time with pedestrian toothpaste or any swivel mechanisms, just shuck and replace. Know that the Kawaski had a "thinking" 2.4 float seat whereas Suzuki used a 2.0 something. At least i can tell from a Keyster labeled replacement. But 2.0 would work just fine with a stock engine. Anyhoot, one can interchange these BS34 parts around between models noting there is a difference in the needle and seat. But ya can't easily effectually put one kawasaki needle into a suzuki seat and vice-versa, they operate within perimeters of each other. Heres a pic of a suzuki Keyster set set into an early J carb set, works just fine, A might expansive but more info is better then just someone blurting crap out. Pictures are cool. Also make sure you didn't just jam that 1.5x7mm float seat oring home, needs a little fingertip of oil to get it seated. You can buy those at any hardware store if you messed-up  

Hey Clay,
With BS34's, more times than not, I ditch the float valve assemblies.  The carbs in question here are Keihin CV34's though, and as the photos show, the float seat doesn't come out.

And speaking of the float seat, that one photo shows a ring of black crud on the needle seating surface.  I wonder if that black is rubber transfer from the float needle?  Looks like you found the problem.

And speaking of needles, real deal Keihin and Keyster are the only brand needles that I've found that will hold up the weight of the float.  They are worth the trouble to chase down...

ED You are 100% correct!! I have no clue why i was thinking the "other 34's". But i see the crap down the opening as you mentioned! I just use a tube and a wad of 0000 steel wool jammed in the tube, then twist it in the opening. But maybe relevant ramblings for the person that has the "other" removeable seats? Ironically though i do pull the seats out of the one's that aren't supposed to ever be removed, just silly like that i guess.  

I hate to say it but that black ring is really just a trick of the light. 




I’m going to polish the seat anyway.

 

Also, if you look close at the photo of the fulls set above, it seems like someone went after switching out the seats on carb 1 & 2 but didn’t get too far. I’m uncertain I wouldn’t f them up