Carbs flooding...

[slavia631]

Just when I thought everything was going fine with my 400, I encountered a brand new problem:  The carbs are flooding.

I just finished putting new O-rings and pilot jet covers on too.  Whenever I try to start the bike, it starts up for a moment and then the carbs flood up and start dripping, and of course the engine begins to flood too.  I have inspected the carbs inside and out, and they are clean as a whistle.  It seems to be the middle two carbs that flood.  These carbs are definitely in need of a sync, but this shouldn't be the reason for flooding should it?  The floats should still cut off the fuel when the bowls get too full right? 

The only problem I can see is that the little nipple on the bottom of the needle valves (opposite the cones) are stuck on two carbs(they don't spring in and out with float-pressure, they are stuck out.)  Odd thing is, that the needle valve springs work just fine on the carbs that seem to be flooding up (middle two).

What could be the problem, and what should I try?

[slavia631]

PS:  It seems to me that they dripping/leaking is coming from the air/fuel mixture screws (the anti-tamper plugs are still on).  With this in mind, I did a little research and came up with this:

its always the idle circuit. Check the jets of course, to make sure they are clear, but its usually the transition ports, which are the tiny holes under the butterfly. You have to remove the mixture screws and idle jets, and flush it both directions. MUST have a solid stream coming out of all the transition ports or it'll still run like poo

So should I start here^ or somewhere else?...

[Chris H]

I'd start with the float as this should shut off the fuel.

[tabby]

Also, check out my earlier thread, just in case you changed the float needles too.

http://forums.banditalley.net/index.php?topic=12422.0

[slavia631]

Thanks for the link!  I did not replace the needles but they do have the little clips on them.  Is this not a stock component?  I wonder if I accidentally deformed them during cleaning or something, and now they are preventing the needles from seating up properly.  This is the first thing I'm gonna check out this weekend... 

[slavia631]

Had some spare time so I took the carbs back apart.  Needles are all seating/sealing just fine.  The only other thing I can think of is that the bowl gaskets need to be replaced.  I inspected them, and the gasket on the most leaky carb seems to be the one in the worst condition, so there could be a corellation.  It is especially worn between the bowl and the transition port area.  So I am thinking the problem may not be carb flooding, but rather that excess fuel is being drawn out of the bowl and through the transition ports. 

I guess I will replace the bowl gaskets and see if that fixes it.  If not, then I am at a total loss...

[905teg]

I guess I will replace the bowl gaskets and see if that fixes it.  If not, then I am at a total loss...

Did you ever fix this problem?

I have a similar problem. My bike has been running perfect for about 4000kms, today I start the bike and it died after 1-2mins idling. Now it won't start.

Things I've tried:

1. Checked for spark (all 4 cyl. have spark)
2. drained the fuel in all 4 bowls (some dirt came out, very little)

After performing #2 the bike started and ran on all 4 cyl's, rode it around the block and then bike loses power and starts running on 2-3 cyl's before dying, won't start and there is a strong gas smell. I look at the carb's and i see fuel dripping from carb #3.

I rechecked all the drain screws, there all tight and secure. I looks like the outside of bowl #3 it's wet with fuel. Can fuel leak from the drain with the screw tight? or is it possibly leaking from the bowl gasket? Are there any other areas fuel can leak (from bottom area of carbs)

After letting the bike sit for 20-30mins, It started up fine after a few attempts. So i go around the block again, it ran smooth for a few mins before its started to run on 2-3 cy's. I pulled over and the bike died as I let off the throttle. Again carb bowl#3 was dripping fuel. I wiped it and started it up, bike started up fine. I rode it again and it was fine, then again it started to run on 2-3 cy's. But this time it kicked back to all 4 cyl's.

note: the carbs do not leak when the bike is off, it only leaks when I ride it for 2-3 mins.

It's late now,so im going to take the bike for a spin tomorrow and see what happens.

My guess is that that carb is not getting enough fuel in the bowl to reach the jets when its leaking, therefore running on 2-3 cyl's. The reason it fires up after 20mins is because the bowl is full or fuel again, until i ride and the bowls start to leak, causing that cyl to cut out.

Any ideas? input?

Thanks

[slavia631]

Hey guy,

I replaced the bowl gaskets and it fixed the problem 100%.  I guess the carbs were not actually flooding; just leaking.
I used the Keyster kit that I found on eBay, which included 4 new bowl gaskets and needle valves.  Worked like a charm.

Good luck!

[905teg]

Today no leaks around the carbs from sitting overnight, I took it for a 20 min ride, no problems whatsoever 

no leaks, no dripping fuel!!

Now if it was the gaskets leaking, why would it be fine today?

I guess I'll have to wait until the problem reoccurs before trying to fix it.

How hard is removing carbs from this bike? anyone have any links to diy removing carbs? any tips when removing carbs on this bike?

[slavia631]

Removing the carbs isn't difficult at all.  Just loosen the intake boots and the carbs slide right off.  The hardest thing is disconnecting the throttle cable from the butterfly.  But it really just takes some fiddling around.  A flathead screwdriver might prove useful.

[PitterB4]

First - it sounds as if you both may have faulty fuel taps.  There should not be fuel coming out of the tank unless there's vacuum. 

Removing the carbs isn't 'hard', it is a major pain, though.  FWIW, I very, very rarely removed the throttle cable.  I did find that to be difficult.  I would just pull the carbs off the intakes and work on them while still connected via the cable.  You'll need to put something like a towel on the frame to keep it from getting beat up but I always found that far easier than dicking around with that stupid cable! 

[slavia631]

My fuel tap ended up being fine.  My bowls were just leaking (after the carbs had filled due to running the bike).