Vent tube gushing gas

[407Jlew]

2007 Vmax turns over just fine but will not start. When turning over, gas flows out of the left side vent tubes. Specifically the left, rear carb.
I've read it could be a stuck float. Could it possibly be a no spark issue and therefore the carbs get full and overflow?
Any ideas would be appreciated before I pull and open up the carbs. Thanks!

 

[MaxMidnight]

It isn't an ignition issue but as you surmise a flooding problem.
If it is the float just sticking on its pivot then sometimes a whack on the carb is sufficient to free it off. Helpful hint: Using a sledgehammer to do this is OTT!

Should that not do the trick then it may be down to some foreign matter preventing the float valve from seating.
You could try opening the drain screw and let fuel flush through. Have something to catch the fuel and no naked lights etc.

If that still fails to help then you will need to remove the float chamber and investigate what is causing the issue.

 

[407Jlew]

Thanks. Would a stuck float on the left, rear carb prevent the other carbs from getting gas since that carb is where the main fuel line is attached? Would it not at least fire if not run on the other three carbs?

I do have another Vmax that is running so I'll do a quick carb swap to make sure the issue is isolated to the bad carbs.

 

[prosnap]

look at my posts and ditch those carbs.

 

[407Jlew]

Prosnap - not quite ready for a carb swap-out but I'll check out your posts. I may do something like that soon... Significant power gains?

 

[prosnap]

Prosnap - not quite ready for a carb swap-out but I'll check out your posts. I may do something like that soon... Significant power gains?

after i mounted it on and adjusted as needed, i took it down to my favorite spot and got on it.,, i was blown away. i will never go back to those crappy carbs ever again. i struggled like just about everybody with those factory carbs.

 

[MaxMidnight]

Thanks. Would a stuck float on the left, rear carb prevent the other carbs from getting gas since that carb is where the main fuel line is attached? Would it not at least fire if not run on the other three carbs?

No, that is only where the fuel is distributed.
Petrol does not need to enter the carb to go to the other three.

I don't ever recall seeing any dyno charts from Mr Prosnap.

 

[407Jlew]

MaxMidnight - the main fuel line goes into a "T" which feeds the that back left carb but I agree that carb does not impede the flow to the other carbs. Which is why I'm surprised that the other cylinders are not firing, even if that one has a float issue. I'm not getting any firing. Just keeps turning over until that vent line start spewing gas...
I'll swap the carbs from my other Vmax this weekend. If it fires up then its a carb issue. If not, then I'll have to keep searching for the problem...
I'll check to make sure the plugs are producing a spark. Prolly should keep those two tests separate from each other!!!

 

[sdt354]

Some heads up roll on video with an OEM carb'd Vmax would rock.

 

[MaxMidnight]

Have you checked that you have sparks at each plug?

 

[407Jlew]

MaxMidnight - Funny you mention that! So I swapped the carbs from a running VMax and no more gas gushing out but still would not fire up. Next I checked the plugs and found no spark. So I swapped the plugs out of the running VMax and it fired up! Then I put the original carbs back on and it fired up and ran but was still gushing gas so I think it was running on just the three carbs. To sum it up I have two problems, bad plugs and a stuck float. Purchased new plugs and will be opening up the carbs this weekend. I'll update this thread once the carbs are clean but I believe I see a light at the end of this particular tunnel!

On another topic - when I got it running I noticed that oil was leaking onto the exhaust and burning up. I haven't investigated that yet but if anyone has any ideas on what that could be (or common places where a VMax leaks oil) I would love to hear them. I'll search this issue on the forum as well...

 

[[email protected]]

Probably need a little more description of where the oil is hitting the exhaust to get some good suggestions.

 

[407Jlew]

I'll dig into it in a few days and provide better detail.

 

[jdeitz1979]

after i mounted it on and adjusted as needed, i took it down to my favorite spot and got on it.,, i was blown away. i will never go back to those crappy carbs ever again. i struggled like just about everybody with those factory carbs.

I’m curious about your set up. If they’re not much bigger as said by another member here in another post, then what makes them perform? I believe that was said they aren’t true 40mm and are 36mm and being just about stock size one would question the need. I mean, factory carbs can be a big pain in the ass, but they can produce really good numbers.
I also looked at your carb and intake pics, I’m not sure about the whole epoxy deal. I think this could create a weak point as far as vacuum, and cause air suction from outside the intake. Besides that, is it even fuel resistant epoxy? I don’t think gorilla glue will work on this application. It seems like gas will sit in the landings and eventually eat away or weaken the epoxy.
Are you running vboost on your set up as well? I would think that vboost wouldn’t be of much use if these are to perform so much better then stock carbs. I’ve seen these on YouTube on a ton of bikes.. but no vmax’s.

 

[407Jlew]

Final update - Pulled carbs apart, cleaned carbs, put carbs back together, went for a ride!