Fuel in exhaust pipe

[TheDawg2002]

I have a '98 VMAX with 9k miles on it. A few months ago, I put on the Cobra 4 into 4 slip-on exhaust (because I like the sound) and left the stock jets. It has been running well, but I decided to go ahead and upgrade the jets to the Dynajet Stage 1. Yesterday, I switched out the main jets for the 170s and I also changed out the needles and springs (all 4 mixture screws were set at 2.5 turns). I synced the carbs, but during the sync, I noticed the front left cylinder is blowing gas out of the exhast. I have double checked that all connections and fittings are tight. The cylinder is obviously firing because all 4 carbs are in sync and there is plenty of compression in the cylinder. I am not a mechanic and usually get all of my info from the internet and intelligent people like you. Is there a common reason for dumping fuel into an exhaust pipe, or do I need to break the carb down again? Thank you in advance.

 

[TK3333]

Did you do a plug check? Whats the plug(s) look like and did you confirm spark from it/them?

 

[TheDawg2002]

Did you do a plug check? Whats the plug(s) look like and did you confirm spark from it/them?

Yes. Plugs are all firing well. The most common reason I keep seeing is a "stuck float bowl". I was hoping for an easy way to "unstick" the bowl without breaking down the carb.

 

[TK3333]

I saw a guy unstick one a couple weekends ago with the peashooter in a parking lot. Tapping on it didnt work. His was leaking out of the over flow though. He was burning the fuel goin through the cyl.

 

[02GF74]

The OEM needle valves have a wire loop that engages in the float tang. The purpose being the needle valve is pulled down when the float drops. Maybe worth draining the carb by undoing the drain screw then giving the float bowl a tap or leaning/shaking the bike

 

[TheDawg2002]

Thank you guys for the ideas. I tried the Peashooter and draining/shaking the bike, but I eneded up having to take down the carb and loosen the float manually. Everything is running well now. Thanks again.

 

[maleko89]

I have a '98 VMAX with 9k miles on it. A few months ago, I put on the Cobra 4 into 4 slip-on exhaust (because I like the sound) and left the stock jets. It has been running well, but I decided to go ahead and upgrade the jets to the Dynajet Stage 1. Yesterday, I switched out the main jets for the 170s and I also changed out the needles and springs (all 4 mixture screws were set at 2.5 turns). I synced the carbs, but during the sync, I noticed the front left cylinder is blowing gas out of the exhast. I have double checked that all connections and fittings are tight. The cylinder is obviously firing because all 4 carbs are in sync and there is plenty of compression in the cylinder. I am not a mechanic and usually get all of my info from the internet and intelligent people like you. Is there a common reason for dumping fuel into an exhaust pipe, or do I need to break the carb down again? Thank you in advance.

170 DJ size? Way too rich as Cobras are very restrictive. I’d reset with stock jetting except with 150 mains….160 if you don’t have those. Reevaluate and then try dj 170 or 185 pilot air jet #2.

Cheers.

Mark

 

[dannymax]

Sounds like the floats need adjustment as well as other mentioned suggestions.

 

[Fire-medic]

I keep float valves on-hand, and if I have to remove the carbs, I replace 'em. Checking the seat is a good idea, of course. Any occlusion or debris there will cause problems for you. I usually use a small round mechanic's mirror and a Q-tip to check for deposits and any sediment.

I don't know how-many times over the years I've used a socket extension or something else long-enough to tap the carb body/float bowl to stop a dribble of gas.