cv carb leaking

[ridemyEVO]

Guys I got a problem with a brand new CV carb that got shipped to me that I installed on my 89 flhtp. The thing runs great, performance is an unbeleivable improvement from the old cv carb, but the darn overflow pipe will start leaking only when the bike has been sitting for 1/2 hour or more when I leave the petcock in either on or reserve position. If I turn petcock to off there is no leaking. If I take cap off the gas tank there is no differnce so its not a pressure thing. The guy who does these carbs has been great and even asked me to send it back in for a check over but problem is I would be without a carb for 4 week turn around time. Donated my old carb to a buddy that built up an evo. The guy said to check the float that it was set to .724 from the base and with carb on its side enough to where the float needle is just touching the float needle spring pin which is what I did. But also just had a thought, I know in this pic thats not the way to measure but as you can see the zinear caliper measuring from the base to the top of the float well I got one measurement where as if I go to the opposite side and do the same measurement I get either a higher or lower measurement meaning the float is not sitting equal distance from the base on both ends. Sorry for long winded post just thinking in the moment.By the way I checked the drain screw as well and its fully closed as well I flushed out the float needle and seat.



Thanks
Lynn

[moosemush]

If the floats are uneven from side to side then you need to even them out. Also inspect the tip of the needle for wear. Sometimes just cleaning them works but not if it's too worn to seat. That's an early CV, maybe 20 yrs old and probably has a good amount of miles on it.

[CraigArizona85248]

Well, that's not a brand new CV carb based on the float picture. They have used rectangular black floats since around 1992. I would suspect either the needle or seat is dirty or damaged. Get a bright light on the seat and eyeball it.

-Craig

[ridemyEVO]

Actually your quite correct thats its not the newer modern style carb as I learned with that type of float but it has been rebuilt to new condition including all new parts. To me the float seems a bit delicate for bending to straighness but I will pull it apart and see what I can do.

[War Horse]

Just wondering out loud here, but did you also replace the fuel feed line? I've seen quite a few hoses deteriorate internally and the rubber silt getting between the needle and seat.

[ridemyEVO]

Just wondering out loud here, but did you also replace the fuel feed line? I've seen quite a few hoses deteriorate internally and the rubber silt getting between the needle and seat.

I replaced the hose 2 years ago but I think I will do it again just so it's out the picture.

[Diver625]

Sometimes when a piece of dirt is stuck in the needle and seat you can shut the gas off and run the bowl dry. This drops the float and opens the needle wider, when you turn the gas back on the flow will wash the dirt out.

[JBarrettB]

As others have suggested look at the needle and inlet seat. The needle can be replaced with new, but the seat is part of the carb body. The seat can be carefully lapped if it is not too bad. Sometimes all it takes is a piece of steel wool turned in the seat with a Phillips head screw driver to clean it up.
Carefully even out the float side to side. As for the float height. Set the round float with the carb completely upside down...no angle like the later rectangular float carb. Last the range for the float is .690"-.730". I suggest that you set closer to .700". At .724" you can deplete the fuel in the bowl under high demand situations causing running problems.

JB   

[ridemyEVO]

Sometimes when a piece of dirt is stuck in the needle and seat you can shut the gas off and run the bowl dry. This drops the float and opens the needle wider, when you turn the gas back on the flow will wash the dirt out.

I did remove the float and needle and gave the seat area a shot of  compressed air.

[ridemyEVO]

As others have suggested look at the needle and inlet seat. The needle can be replaced with new, but the seat is part of the carb body. The seat can be carefully lapped if it is not too bad. Sometimes all it takes is a piece of steel wool turned in the seat with a Phillips head screw driver to clean it up.
Carefully even out the float side to side. As for the float height. Set the round float with the carb completely upside down...no angle like the later rectangular float carb. Last the range for the float is .690"-.730". I suggest that you set closer to .700". At .724" you can deplete the fuel in the bowl under high demand situations causing running problems.

JB   

I always thought the .730 was toward the lower level. So if I can get the float evened out and set it to .690 the very low level end just for testing to get it to stop leaking it should work right?

[JBarrettB]

I always thought the .730 was toward the lower level. So if I can get the float evened out and set it to .690 the very low level end just for testing to get it to stop leaking it should work right?
[/quote]

Float height only sets the level of the fuel in the bowl. Set at .690" would put the fuel level in the bowl at maximum. The problem you have is that that needle and inlet seat are not stopping flow into the bowl, not something that messing with the float height is going to cure.

JB

[ridemyEVO]

Jb that is of course unless the float being adjusted is not level all the way across right?

[ridemyEVO]

I connected a clear hose to the float bowl drain pipe and before I even opened the
Drain screw there was gas in it and once I opened the screw the gas in the
Hose was way above the top of the bowl joint to body.
Ok I'm going to start over with float setting, if I turn carb upside
Down like in my pic in post 1 won't the Float needle pin be compressed?

[Norton Commando]

With the carb upside down, the weight of the floats should force the needle against its seat.  In fact, with the carb in this upside down position and with your mouth on the inlet, try to blow air past the seat. If you can, then you have a damaged needle or seat. 

[hbkeith]

like Caig said ,did you look at seat with bright light ? its the needle or seat

[JBarrettB]

One last thing I thought of...make sure that the float itself does not have a hole in it causing it to sink in the bowl. It must float after all.

JB

[ridemyEVO]

I did turn up side down and blew into it and it held fine. I also checked the seat and float needle and it looked fine and blew it out again.
I reset the gap again to .700 and put the clear tube on the drain pipe and it was much lower against the bowl but still started leaking after 45 minutes or so. The way I did the .700 was I tilted the carb enough so the float needle was closed and the float was just touching the float needle pin ( not compressing it). Again I ask to confirm if I stand the carb upside down and set the the float level its going to compress the float needle pin and this is fine to do it just the way the picture is showing?

[ridemyEVO]

One last thing I thought of...make sure that the float itself does not have a hole in it causing it to sink in the bowl. It must float after all.

JB

Yes I did check the float and no air bubbles.

[JBarrettB]

Set it upside down.   

JB

[hdbikedoc]

Check the overflow tube sometimes they get a hole in them ,i have seen it anyway I just put some heat shrink on the tube the kind with the glue on the inside and thats the fix if this is the problem

[ridemyEVO]

I turned the carb upside down like showing in my pic and set it to .700. So I will have to see in an hour if it leaks or not.
JB I seen the setup info in my manual but it was a bit confusing as they give the upside down info for the 91 that have the 3 sides float needles. Mine has the round float but with the 4 sided float needle and it says if you upgrade to the 4 sided float needle follow the float setup for the 92 and on which is the tilt method. This is a Killer Carb by Dale as found on ebay and he told me to tilt the carb until the float just touched the float needle pin and set it to .724. The only reason I'm trying to figure this problem out is although he wants me to return it, it would be 2 weeks for me to get it to him and another 2 weeks back to me, damn customs slows everything right to a crawl. Not trying to be a pain just trying to get this working.

[mkd]

i would guess your needle and seat is leaking !shutting the fuel off elliminates the gravitational flow from the tank but all the gas in the line below the petcock can still leak by.the float level has to be below the overfill tube pickup but once that is accomplished float level should have no influence on your problem.

[ridemyEVO]

i would guess your needle and seat is leaking !shutting the fuel off elliminates the gravitational flow from the tank but all the gas in the line below the petcock can still leak by.the float level has to be below the overfill tube pickup but once that is accomplished float level should have no influence on your problem.

I hear you, I'm about ready to ship this carb back.

[ridemyEVO]

Well thats that it leaked. I think I;m going to have to just send it back for a replacement. 

[Grayrider]

Why don't you try setting it at .750 which would be overkill and see if that shuts it off. If you are saying your needle is not bleeding past then it must be the float level that is allowing the needle to open and leak!  Assuming good floats. The float dictates fuel level by opening and closing the needle and also supplying enough fuel to run well.
If the needle is good, pressure from the float set right will stop it leaking past. And if it does stop the leak, then you need to determine if that would supply enough fuel to the carb for WOT.