How is this possible?

[Mopheos]

Sorry about asking so many questions, but I do appreciate all the help from the forum. I just removed the carb assembly from the bike, and as I look into the ports of the VBoost(?) which each flow into the cylinder heads, the number two port and the number three port both have gas standing in them. I don't know what this means, but somehow it doesn't seem good. Any ideas?

 

[naughtyG]

I think it's simply because gas kept pouring through as your needle valves didn't seal.

However, it's worrying if it keeps going when the bike's been off for a day. This could mean there's a different problem. Here's why:

- gas lives in the tank. It can only come to the carbs when pushed through by the fuel pump.
- once the bike's switched off, so is the fuel pump, so the only gas you now have in the system is 4 x fuel bowls' worth
- even if all four needle valves are shot, only the fuel bowls' contents will weep into the cylinders, then it'll stop (out of gas)

To get into the fuel bowls you only need to break the carb rack into pairs. I went the whole way in my write up because I wanted to clean them thoroughly while I had them out.

If you're not confident doing this, there are a few people here (Maleko, Sean, myself) who you could send your carb rack to in order to have it all done.

 

[Mopheos]

Thanks NG. What do I do about the gas that is standing in the no 2 & 3 vboost ports? Is there a way to purge it?

Oh by the way, I checked the vboost operation, and it appears the vboost is kaput, too. Dang. That PO told me the carbs had just been rebuilt when I got the bike last October, but I think my non-mechanical son could have done a better job. I have enough confidence (and I think experience working on cars, carbs, motors, etc) to break the carbs apart and clean/rebuild them. What do you guys typically charge for such a service? You might tempt me to think otherwise :^)

 

[jfeagins]

Fuel bowls remain full all the time, running & just sitting around.

For the fuel to continue running after the bike is shut off, the inlet needle would have to be stuck open AND then the only gas to continue trickling downward would be the amount of gas UP from that valve in the gas lines.

If the fuel pump is working properly, I'd think it would take a long time, very slowly, for the gas in the lines to finish trickling down through the carbs and on into the motor.

UNLESS, by some chance the fuel in the lines has a suctioning effect and is pulling gas all the way from the tank while the bike just sits there. It might be possible for the gas to continue syphoning off in this fashion until such time as the gas level in the tank becomes equal to the level of the floats in the carbs.

Did you, by chance, use compressed air at any time during your recent fuel pump repair or blow out any crap from the fuel lines?

I'm betting you will need to get the carbs off and go through your inlet valve assemblies to fix this one.

Don't light too many cigarettes in the garage until after you get this one figured out.

 

[tugla]

Fuel bowls remain full all the time, running & just sitting around.

For the fuel to continue running after the bike is shut off, the inlet needle would have to be stuck open AND then the only gas to continue trickling downward would be the amount of gas UP from that valve in the gas lines.

If the fuel pump is working properly, I'd think it would take a long time, very slowly, for the gas in the lines to finish trickling down through the carbs and on into the motor.

UNLESS, by some chance the fuel in the lines has a suctioning effect and is pulling gas all the way from the tank while the bike just sits there. It might be possible for the gas to continue syphoning off in this fashion until such time as the gas level in the tank becomes equal to the level of the floats in the carbs.

Did you, by chance, use compressed air at any time during your recent fuel pump repair or blow out any crap from the fuel lines?

I'm betting you will need to get the carbs off and go through your inlet valve assemblies to fix this one.

Don't light too many cigarettes in the garage until after you get this one figured out.

might tell if there was suction by undoing the gas cap, if you hear any depressurization in the tank. also if the carbs not set up right, throttle blades way too open, that might also be helping sucking fuel just after shut down no??? i could be way out to lunch on that one. was thinking the needle too far out of the jet and pulling too much fuel cause its off the idle circuit a little.

 

[Mopheos]

As per my first comment in this thread, I did ride 10 or so miles after I noticed gas leaking under the bike, and the bike ran really crappy the whole 10 miles home. Could I have been pumping gas into a cylinder whose plug was fouled and so not burning the gas but just filling up the intake manifold? The thing sounded like it was running on 2 or 3 cylinders, and the exhaust even sounded different, like I could hear valves faintly ticking or something. I have removed the carbs and will rebuild once the parts from Sean come.

 

[naughtyG]

I think you'll find plenty of fine rust dust in your carbs. Use plenty of carb cleaner spray and compressed air, just like I did, and by the time you'll put 'em back together and sync them it'll run like a champ again!

Also if you're feeling it, you'll be alright doing it yourself

 

[tugla]

ya for sure sounds like crap plugg'in up the needle and such, sometimes a little bath and TLC is all they need.