68k miles. so i go to ride to work last week and when i park the bike it starts idling down and loading up then starts pissing fuel out the air filter. so i shut the fuel off and go get a screwdriver and tap on the bowl figuring the needle is stuck. no effect, still pissing. manage to get it home and take it apart, needle and seat look fine but i order a james geniune and rebuild it anyway. float height is at spec .413-.453. put it all together and turn the fuel on and she runs like a champ no overflow. leave the bike at home, standard petcock on, no vac assist and go to work. come home and pissing everywhere! im pissed now, i pull the vapor valve forward of the tank and it appears to be stuck, pressurizing the tank and forcing fuel past the needle valve. remove the valve, thought i had it fixed, nope still pissing. adjusted the float to .500 and had an effect but still pissing slower. ordered a new float and waiting for the part. no debris whatsoever in the fuel inlet or bowl at dis assembly. the float appears to have no fuel in it and floats in a can of gas. im simply replacing it to eliminate it from the equation. any opinions out there? and why the f#$^ is there no overflow tube on these carbs, just up through the mainjet and straight into the intake manifold headed for an open intake valve and passed the rings???????

 

You replaced the needle and seat?

 

the seat is pressed in and non replaceable. the needle is rubber tipped so rarely wears the seat. i gotta believe it's the float. when the new one comes in the mail im going to weigh them both to determine if the old one is leaking. im tinkering with it now and i swear all seems well. float level is to spec and when i apply light pressure on the float to seat the needle valve i cant push air passed it when blowing on the fuel inlet hose. i want to put it back together and try again but im just gonna wait on the new float. once again thanks for the reply.

 

I ALWAYS start with the needle and seat. I just replaced 4 (Yamaha YX600S) this month. All 4 looked perfect. 2 were known leakers. Replacement fixed the issue. Floats are still the oroginal nitrophyl from 1986. I've been rebuilding carbs for 30 years on cars and bikes as old as the early 60s and have NEVER had to replace a float.

Your mileage may, of course, vary.

 

i agree with you and cant find anything wrong with the float!!!!!!!!. thanks again for your opinion and your experience. ill throw it back together and see what happens. as stated the cv seat isnt avail for replacement???????

 

put it back together and all was fine. rode it around the block and back to the garage and it ran perfect. ran it without the air filter on and noticed fuel vapor dripping from the crankcase vent so pulled the drain plug to change the oil. this thing has probably had a quart of fuel past the rings!. while i was sitting watching the oil drain it started wicking fuel up and around the accel pump nozzle and the air ports for the slow and main jets in the carb throat. it has got to be the f'ing float!. pulled the bowl and it was overfull. the original vac operated petcock started leaking awhile back so i simply replaced it with a standard on/off valve. is the CV carb float strong enough to hold back static fuel pressure from the tank if the petcock is left on while the bike is sitting? i know im reaching, but this is starting to pis me off.

 

So, are you going to start shutting your petcock off now?

 

that would be the logical answer now wouldn't it! for the past year i have simply left it on with no problems. i dont feel that i should have to gas on gas off every time i start the bike. you couldn't walk in to pay for the gas you were about to put in it without it pissing! ill figure it out. i do appreciate your input though so thanks for your 02 cents. i am laughing at my frustration so it's all good.

 

i ended up focusing on the needle seat per the advice here. under a bright light and magnifying glass the seat looked rough and had deposits stuck to it. i lapped the seat with cutips and mothers until smooth and polished, put it back together and no leaks!. thanks again, and yes ill start turning the gas off if the bike is going to sit unattended for more than a few minutes. forums like this are the best part of the internet

 

I had the same issue with my CV 40 in my 1995. Only mine became a "drivability" problem. Ended up replacing all the jets in the carb. My needle came out with a very small "tip" that was eroded from the ethanol in our wonderful fuel. I never had a problem with "pissing" as I always shut off the petcock. (Never trusted that funky vacuum diaphragm.) Anyway, I had to do this every 10-15,000 miles or so because of the damn ethanol. Traded that bike in on a fuel injected Dyna, so I hope this cycle has ended.