Fuel pump wont stop running, dumping large amounts of fuel into cylinders

[dodgediesel59]

So i fired bike up today to put fuel in it. It ran great the other night and tonight it acted like it was missing on 1 or 2 cylinders. I got back and thought ignition as I just put an ignitech unit in the other night that i rode it. So i checked spark at all 4 COP's and all of them had awesome spark. So i pulled plugs out and right 2 looked super fouled. I noticed when i kept turning key on and off that the fuel pump just kept running. So I disconnected the fuel pump wire and ran the bike and it cleared out in about 2-3 seconds and ran perfect until it got low on fuel in the bowls. I thought maybe it was the relay unit under the left scoop and tried one out of my buddies and same thing. I put a vice grips on the fuel line before the carbs and tried it and it clicked once and was done. So question is, what is causing this? Carbs on bike were redone totally over the winter and floats and valves all looked in good shape and have worked fine for the 2,000 miles I have put on this year. Any help would be great as I am ready to push this bike down the hill.

 

[dingy]

Are you dumping gas out of any of the overflow tubes? These probably exit in front of the rear wheel somewhere.

Maybe a stuck float.

By clamping the fuel line, it indicates the diaphragm in the fuel pimp is good & sensing the pressure build up.

Gary

 

[dodgediesel59]

No fuel out of any of the overflow tubes, its going straight into the engine. I am going to pull the air box tomorrow and try to clamp off segments of the carb fuel divider hose and see if it is only occuring on one side or both. Any other thoughts?

 

[sdt354]

No fuel out of any of the overflow tubes, its going straight into the engine. I am going to pull the air box tomorrow and try to clamp off segments of the carb fuel divider hose and see if it is only occuring on one side or both. Any other thoughts?

Hmmm, how about the bowl drains? They closed? Bowl plugs and gaskets. Just an easy place to start.
After you sort that out I'd like to hear about the ignitech. Did you leave it the way Gary set it up?
Steve-o

 

[dodgediesel59]

Yea, everything is closed up no external leaks of fuel. I will try to pull the air box off today as that should give me a good idea where to start. Is it possible dirt or grime got into the needle assembly and thats why its all of a sudden having these problems? Needle valves dont usually just fail out of the blue do they?

 

[SpecOps13]

My 89 does this when a float sticks from crap getting into a carb. Gas overflows into the front left cylinder at times... It's the one carb that ends up with any trash that gets past the fuel filter... The bike will still run but gas mileage really sucks if it's not cleared immediately...

 

[dodgediesel59]

from the plugs i looked at it appears right front was worst and right rear looked pretty black too. I guess though the front carb could feed the rear as my v boost is always on.

 

[SpecOps13]

If one of the left side plugs appears to have a whiter insulator, that's the one that's overflowing. It can't fire the enormous amount of fuel so the plug insulator gets washed...

 

[dodgediesel59]

Would it cause a richer condition on the otherside in this process? The whiter plugs didnt appear to be wet at all.

 

[SpecOps13]

Very similar to what I saw with my 89 and still do at times. The 1,3,4 plugs will be darker than normal and the #2, Front Left will be like a new plug. I drain the front left carb into a cup and it will have some tiny black flakes in the gas that comes out.. My tank is clean, new fuel filter, new lines so it must be the carbs inlet has some rust... 99.9% of the time, the bike's running fine...Hopefully it will eventually be cleared out totally...

 

[sdt354]

from the plugs i looked at it appears right front was worst and right rear looked pretty black too. I guess though the front carb could feed the rear as my v boost is always on.

I'd be interested in the outcome of this D. Let us know, k? In the past I've always had gas flow out the vents when something causes the bowls to overfill. I'm thinking the floats are ok and something below the fuel level is a problem.
Steve-o

 

[m-cman]

If your gas lines are original they may need to be replaced with ethanol resistant lines. My old lines kept disintegrating a little at a time until replaced with modern gas lines. A few little black specks would show up in various places in the carbs.

 

[dodgediesel59]

Well yesterday I finally got a chance to work on it. I pulled the air box off to get down to the fuel divider hose at the carbs and clamped off the hose to the left front carb and it cycled key and it worked fine. Took clamp off and it still worked fine. Put it back together and rode the piss out of it with no issues. Parked bike for an hour went to ride with my buddy and the bike ran great but if cruising and then you accelrated it would have a stutter or miss and then run like a champ.

 

[SpecOps13]

Have you drained the front left carb into a clean jar or cup? Just hold the cup under the black hose under the carb and turn
the drain screw out. It's on the right side of the carb body. Sounds like it broke free but is intermittantly reappearing...
You'll likely find some particles in what comes out. They'll just set there and cause you further problems without doing this...

It's about a 2 minute job to turn the screw out and back in... Once you've done this, it wouldn't hurt to check the other 3 too...

 

[dodgediesel59]

So this can be done without removing the air box? I hate having to take the scoops off:bang head: :angry flame:

 

[SpecOps13]

No Air Box or anything else needs to come off. All it takes is a Phillips Screwdriver long enough to reach the Drain Screws. Just above the rubber boot the carbs set into, right side of each carb. You'll be sticking the screw driver in just under the the right side of the diaphragm covers. The actual screw is slotted so really either straight or Phillips could be used. The hose sticks out just under the carbs.. Clean jar or Paper Cup works fine. Good Luck.

 

[[email protected]]

Clean jar or Paper Cup works fine. Good Luck.

Just don't use a Styrofoam cup:biglaugh: if you've ever done that you know what I mean!

 

[dodgediesel59]

Drained bowl and there was a little bit of stuff in there, but did not affect the way it ran one bit.

 

[dodgediesel59]

You guys think Its time to pull the carbs and split em and give em a good clean again? cant beleive they are dirty already. I guess I am going to replace the fuel lines while i am at it.

 

[SpecOps13]

If you are using Ethanol, replace the fuel lines with line approved for Ethanol. Also, when you do get it running right, use an additive to counteract the Ethanol's Effects. When I have to use Ethanol, I use Sentry because it is made right here and it works... Otherwise the bikes run like crap... I normally use Non Ethanol...

Personally, I'd drain the carbs a few more times after running then move on to more drastic measures..

Good Luck...