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06-10-2015, 02:01 PM, (This post was last modified: 06-10-2015, 02:18 PM by lukerasta.)
#1
Fuel coming out of the exhaust....
Hi guys,
I did a quick search, but couldn't find an answer. I have a 1999 yamaha v star Classic with aftermarket pipes on it. I started the bike up the other day to go for a ride, and the bike was idling really rough. After it warmed up a bit, there was a strong fuel smell, gas dripping out of rear cylinder exhaust pipe and out of the overflow nipple on the carb. The part that I found interesting though, is that the bike runs great when the fuel petcock valve is shut off. With the bike shut off, I will turn the petcock on for 15-20 seconds then shut it off. Turn the bike on and it runs great....until, 1 - the carb starves itself of fuel, or 2 - I turn the fuel on. Within seconds of turning the petcock on, it starts running really rough again.

I bought the bike 2 years ago, and the guy before me had parked the bike for 3 years with the fuel petcock left on, so the carb was clogged right up. The mechanic that cleaned the carb said that it was really bunged up, and he wouldn't be surprised if I had future issues with it (if a tiny piece lets go and plugs a jet or something).

I've taken the fuel bowls off a couple times since this started about a week ago. Both times, I've used Sea Foam inside the carb, as well as lightly taping the float valve, incase it wasn't seating properly. I also mixed up some Sea Foam into the fuel tank. Due to my tinkering, the problem has gotten better, but still not fixed enough that I can ride the bike.

This morning, I switched the float assembly (front float, valve, etc. switched with the rear carb, and vice versa). My hope was that the fuel would now come out the front cylinder, that way I would know that the problem is in the float assembly. No dice, still coming out of the rear cylinder.

I'm out of ideas now. Has anyone ran into this before?
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06-10-2015, 02:54 PM, (This post was last modified: 06-10-2015, 02:55 PM by Maustarman.)
#2
Fuel coming out of the exhaust....
I would say that in the rear carb assembly there is something that keeps the float from closing ...
Did you inspect the float valve? Sometimes especially if the bike have been sitting for a long while there is bad fuel build-up crap that destroys the rubber seal in the valve...
Compare it with the from one and also check that there isn't anything in the way of the float
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06-10-2015, 04:51 PM, (This post was last modified: 06-10-2015, 05:01 PM by pauli466.)
#3
RE: Fuel coming out of the exhaust....
(06-10-2015, 02:01 PM)lukerasta Wrote: Hi guys,
I did a quick search, but couldn't find an answer. I have a 1999 yamaha v star Classic with aftermarket pipes on it. I started the bike up the other day to go for a ride, and the bike was idling really rough. After it warmed up a bit, there was a strong fuel smell, gas dripping out of rear cylinder exhaust pipe and out of the overflow nipple on the carb. The part that I found interesting though, is that the bike runs great when the fuel petcock valve is shut off. With the bike shut off, I will turn the petcock on for 15-20 seconds then shut it off. Turn the bike on and it runs great....until, 1 - the carb starves itself of fuel, or 2 - I turn the fuel on. Within seconds of turning the petcock on, it starts running really rough again.

I bought the bike 2 years ago, and the guy before me had parked the bike for 3 years with the fuel petcock left on, so the carb was clogged right up. The mechanic that cleaned the carb said that it was really bunged up, and he wouldn't be surprised if I had future issues with it (if a tiny piece lets go and plugs a jet or something).

I've taken the fuel bowls off a couple times since this started about a week ago. Both times, I've used Sea Foam inside the carb, as well as lightly taping the float valve, incase it wasn't seating properly. I also mixed up some Sea Foam into the fuel tank. Due to my tinkering, the problem has gotten better, but still not fixed enough that I can ride the bike.

This morning, I switched the float assembly (front float, valve, etc. switched with the rear carb, and vice versa). My hope was that the fuel would now come out the front cylinder, that way I would know that the problem is in the float assembly. No dice, still coming out of the rear cylinder.

I'm out of ideas now. Has anyone ran into this before?
get a float needle kit and install it take no chances go with new. you don't need the aggravation of breaking down 100 miles from home over a 25.00 fix. if you keep playing around you'll mess up the float levels sooner of latter. the float tangs should be horizontal/level as a starting point for adjusting. also you can put hose on the drain nipple and hold it above the carb bowl then open the drain screw. if fuel comes out you'll know the float is stuck of the needle dirty or bad. on 1999 bike just change em.
Reply
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