Gas leaking from carburetor - '05 Ninja 250

[smilingthai]

Have taken my carbs apart twice to remedy this issue to no avail. This last time I replaced the float valves, pilot screw and float gasket; it's still leaking, although, not as bad as it was before. Any thoughts and/or suggestions would be greatly appreciated. I love my bike...I don't love my carburetor right now.

[xXecuterXx2]

Originally Posted by smilingthai

Have taken my carbs apart twice to remedy this issue to no avail. This last time I replaced the float valves, pilot screw and float gasket; it's still leaking, although, not as bad as it was before. Any thoughts and/or suggestions would be greatly appreciated. I love my bike...I don't love my carburetor right now.

first thing is to identify where the leak is coming from, it may just be your bowl drain screws.

[choneofakind]

Float bowl seals. When mine were old, the bowls would leak the first time I put gas in them after being put away and/or drained for work. After a while, they'd swell up and seal again, but it would take a few hours of contact with gas to seal and they would drip once in a while.

Got new seals and the problem has been gone since.

[Ghostt]

As the others have already said, you must find out where the leak is coming from, it could be a number of causes.

I suggest PM @ducatiman for all your carburetor needs, he's very affordable.

https://www.ninjette.org/forums/showthread.php?t=226815

[Motofool]

Welcome, Linda !!!

The seats (orifices in the aluminum body) of the float valves may have some hard deposits that interfere with the proper seal of the soft tip (neoprene) of the part that you replaced.

If that is true, a cotton tip, a drill and some dental paste could help.

[smilingthai]

Thanks for the warm welcome! Really makes one feel the love!
Thanks for all of the suggestions too! I haven't started my bike again since yesterday but from what I remember the leak seems to be coming from somewhere at/around the carb stay plate/throttle screw area. I will try starting it again tonight when I get home and update but I'm pretty sure that's where it is. At first I did think it was from the drain screw or overflow area but realized it was dripping from somewhere higher up.

@choneofakind - is the float seal the same as the float chamber 0-ring? If so, I changed that as well. Actually, that was one of the things my bike mechanic did before I pulled the carb off the first time months ago. Just put two new ones in this time because they came with the repair kit.
@Motofool - how do I go about this cleaning with toothpaste, drill, and cotton swab? I'll definitely try it; at this point I'll try anything.

[csmith12]

Welcome Linda!

Good luck with your leak.

[Ghostt]

@smilingthai

Did you set the float height?

[choneofakind]

Originally Posted by smilingthai

@choneofakind - is the float seal the same as the float chamber 0-ring? If so, I changed that as well. Actually, that was one of the things my bike mechanic did before I pulled the carb off the first time months ago. Just put two new ones in this time because they came with the repair kit.

Float bowl seal/o-ring/gasket/whatever you want to call them. Yeah, they're likely the same thing.

[liquidnine]

I was in the same boat this summer, taking the carbs apart twice trying to pinpoint the leak. In my case, it was torn tubing in between the two carbs. It was hard to see, given the location, even with the carbs off the bike. I had to use tweezers to remove the tiny hose clamp. I trimmed the tube down to excise the tear and reconnected the hose.

[smilingthai]

Originally Posted by liquidnine

I was in the same boat this summer, taking the carbs apart twice trying to pinpoint the leak. In my case, it was torn tubing in between the two carbs. It was hard to see, given the location, even with the carbs off the bike. I had to use tweezers to remove the tiny hose clamp. I trimmed the tube down to excise the tear and reconnected the hose.

Thanks for sharing this. Would have never thought to look there. Did this fix work for you

[liquidnine]

Originally Posted by smilingthai

Thanks for sharing this. Would have never thought to look there. Did this fix work for you

Yep! To go in to a little more detail, when the bike was running it looked as if the leak was coming from the float bowl gasket area. I had a flash light out, looking as closely as I could trying to find where the leak was coming from. When I turned off the petcock, the leak would stop pretty much right away. I figured it was a bad gasket (replaced twice) or a float problem. I was ready to give up and take the carbs to a shop before I found that little torn hose.

I changed my oil after the leak was fixed, just in case the dripping gas contaminated the oil.

[smilingthai]

Originally Posted by liquidnine

Yep! To go in to a little more detail, when the bike was running it looked as if the leak was coming from the float bowl gasket area. I had a flash light out, looking as closely as I could trying to find where the leak was coming from. When I turned off the petcock, the leak would stop pretty much right away. I figured it was a bad gasket (replaced twice) or a float problem. I was ready to give up and take the carbs to a shop before I found that little torn hose.

I changed my oil after the leak was fixed, just in case the dripping gas contaminated the oil.

This is exactly what was happening to my bike. I really hope this is my fix as well! Thanks again

[MasterCylinder]

I know this is an old thread but which hose exactly did yall have to replace? Can you post pics?

I have the same issue and still haven't resolved it.

[ducatiman]

if not bowl orings leaking, possible the orings on the fuel crossover tube?

(yours will be black nylon, example pic from an older 250)

and vacuum hoses between carbs do not carry fuel

Note carbs will need to be split to replace the fuel tube orings.

[liquidnine]

Originally Posted by MasterCylinder

I know this is an old thread but which hose exactly did yall have to replace? Can you post pics?

I have the same issue and still haven't resolved it.

I used DucatiMan's image since it shows the hose that gave me problems. I had a tear where the arrow indicates. It was a tiny tear. When it leaked when the bike was running, the gas appeared to come from the top of the float bowls. I trimmed that hose a little to get rid of the tear and had enough left where it could be reconnected without pinching or kinking anywhere. I had to use tweezers to get the hose back on...it's cramped in there!

[HoneyBadgerRy]

Originally Posted by liquidnine

I used DucatiMan's image since it shows the hose that gave me problems. I had a tear where the arrow indicates. It was a tiny tear. When it leaked when the bike was running, the gas appeared to come from the top of the float bowls. I trimmed that hose a little to get rid of the tear and had enough left where it could be reconnected without pinching or kinking anywhere. I had to use tweezers to get the hose back on...it's cramped in there!

I believe that hose delivers fuel to the coasting enrichener. Just do down to your local hardware store, buy some gas line, and replace it.

You might want to replace the rest of your fuel and vacuum lines on your carbs where your in there. Also replacing the JIS screws with stainless steel allens so next time your carb work is less of a headache.

[ducatiman]

the hose marked in red is a vacuum hose

[HoneyBadgerRy]

Originally Posted by ducatiman

the hose marked in red is a vacuum hose

Don't vacume lines have to be after the throttle plate? What causes the vacuum if there is no restriction to open air?

[RacinNinja]

Originally Posted by HoneyBadgerRy

Don't vacume lines have to be after the throttle plate? What causes the vacuum if there is no restriction to open air?

No.

That's in the venturi and subject to the effects it creates. IE, vacuum.

[RacinNinja]

It turns out one of the drillings for that passage is on the intake side of the butterfly. So, it looks like it's both yes and no.

To compensate for this there's an air jet in the lower diaphragm chamber that transfers ambient pressure to one side of the coasting enricher's spring-loaded cut off valve. The excess vacuum in front of the butterfly valve is transferred to a drilling that leads to the other side of the cut off valve. This sucks it open, allowing the pilot jet to feed more fuel to the engine, preventing an overly lean condition. (Pop. Pop. Pop.)

[HoneyBadgerRy]

Originally Posted by RacinNinja

It turns out one of the drillings for that passage is on the intake side of the butterfly. So, it looks like it's both yes and no.

To compensate for this there's an air jet in the lower diaphragm chamber that transfers ambient pressure to one side of the coasting enricher's spring-loaded cut off valve. The excess vacuum in front of the butterfly valve is transferred to a drilling that leads to the other side of the cut off valve. This sucks it open, allowing the pilot jet to feed more fuel to the engine, preventing an overly lean condition. (Pop. Pop. Pop.)

I wonder how necessary the coasting enrichener is. Many carbureted bikes don't have one. (Not saying it's a good idea to remove it at all.) However, It kinda makes me think it was more of a thing because due to emissions the bikes were jetted lean from the factory.

[RacinNinja]

Originally Posted by HoneyBadgerRy

I wonder how necessary the coasting enrichener is. Many carbureted bikes don't have one. (Not saying it's a good idea to remove it at all.) However, It kinda makes me think it was more of a thing because due to emissions the bikes were jetted lean from the factory.

On my wife's first pre-gen, the diaphragm was rotten so I just deleted the whole thing. Didn't have any issues. Didn't pop on decel but I tuned it....

[HoneyBadgerRy]

Originally Posted by RacinNinja

On my wife's first pre-gen, the diaphragm was rotten so I just deleted the whole thing. Didn't have any issues. Didn't pop on decel but I tuned it....

I always run my needles and below a hair on the rich side, so I'm sure my bike would be fine. That said, there really is no need to delete it.

[RacinNinja]

Originally Posted by HoneyBadgerRy

I always run my needles and below a hair on the rich side, so I'm sure my bike would be fine. That said, there really is no need to delete it.

No, there is not.

That said.....Have you priced that diaphragm? $60 bucks, and that's not from Kawasaki......

Not joking. That was the reason for my delete.

[ducatiman]

i'd think they added the enrichener to compensate for super lean (EPA) pilot screw settings...as racinninja stated he deleted> tuned them> no issues.

It would be interesting to take a stock 250, pilot screws untouched from factory (still capped)
and bypass/plug off the enrichener...I wonder if or how bad it would pop. That would then reveal Keihins motives as to using it at all. As it added manufacturing expense....my guess would be its addition was mandatory to both make the bike behave, meanwhile satisfy the EPA.

[MasterCylinder]

Holy balls! For the life of me I couldn't figure out how to split the carbs when I originally did my rebuild and just assumed it couldn't be taken apart. Now that I figured it out I'm going to pick up some o-rings (hopefully) today to replace these horrible excuses of fuel sealing capabilities since apparently none of the 3 rebuild kits I bought came with the replacement o-rings. Good catch ducatiman!

[ducatiman]

Normal commercially available "carb kits" fail to supply rail (upper vent and lower fuel supply) orings... as the standard "carb clean" not requiring a split. As these bikes are ageing...instances arise where spilt does become necessary. Don't even contemplate a split without orings in your hand....

i stock fuel and vent rail orings within kit form, if you (or any other member) need.

Note the link bar JIS phillips heads are gonna be *real* tight....use a hand impact driver to smack them loose. "Persuasion" is necessary.
When reassembling a split, the choke spring, center spring and throttle lever spring, inner hoses...all tricky to get together in one shot.

Have fun!

[MasterCylinder]

Originally Posted by ducatiman

Normal commercially available "carb kits" fail to supply rail (upper vent and lower fuel supply) orings... as the standard "carb clean" not requiring a split. As these bikes are ageing...instances arise where spilt does become necessary. Don't even contemplate a split without orings in your hand....

i stock fuel and vent rail orings within kit form, if you (or any other member) need.

Note the link bar JIS phillips heads are gonna be *real* tight....use a hand impact driver to smack them loose. "Persuasion" is necessary.
When reassembling a split, the choke spring, center spring and throttle lever spring, inner hoses...all tricky to get together in one shot.

Have fun!

Indeed! I don't think it was that bad. The part that made it bad was the new o-rings on the overflow tube. Just did not wanna go back together even with lube (vaseline). Everything else just fell into place.

You were right about the crossover pipe...

New on the left and old on the right.




I'll put it on my bike sometime later but I'm fairly positive that is going to be the cause of my leak based on proximity. Thanks a ton!

[smilingthai]

Sorry, I haven't followed up. After having my carburetor off my bike more times than I wanted trying to figure out from where the gas leak was coming, I finally found the problem and fixed it. It ended up being this little tube (part #92005B) with 2 gaskets on it that runs/connects between the 2 carbs. Since I had the carbs apart I went ahead and replaced part #92005A as well and one of the vacuum hoses since that was a suggestion as well. And I'm more than thrilled to report that there is NO MORE gas leak and I pretty much have a nicely, overhauled carburetor
Thanks for all the help and suggestions. Now I need to get cables tightened

[CaliGrrl]

Glad you figured it out!