This is the second time this happened. First time it was at work. The bike started to leak fuel out of the car and refused to start.

Took me quite some time to get it started, i changed the oil, the sparkplugs, and opened the carb and re adjusted the carb floats. And it started working. For about 200 miles.

Today, i was as a stop sign and the bike died. I tried to start it, but it refused. It cranked fine. And with more cranking came a strange noise from the engine. Only sometimes this would happen. I parked it and trailered it home.

Looking for ideas on wht could be. I removed the car and the carb float seems to be the same. 300 miles isnt much to go bad i think. The bike rode amazingly well, plenty of power and just railed until it stopped.

Any ideas?

...........Any ideas?

One or both float's valves is (are) leaking due to one or more of three things that may be happening:

1) Punctured/dislocated float, worn needle or worn seat.

2) Debris stuck between the needle and the seat.

3) Tank developing pressure due to increasing temperature and defective vent.

.... The bike started to leak fuel out of the car and refused to start.



Leaking with the bike running or sitting still?
Have you checked the petcock?

sounds like stuck float valve and then overflowing out the top

sounds like stuck float valve and then overflowing out the top

Was there gas in the crankcase oil after the bike sat for a while? Is this happening after the bike sits for a while?

I’m liking Blue’s suggestion of the vacuum-operated valve on the fuel petcock going bad. You can confirm that by turning the petcock to “Off” immediately after shutting off the bike. If the carb(s) stop leaking after that, then you know you need to replace or rebuild the petcock.
(Are rebuild kits available for these petcocks?).

Was there gas in the crankcase oil after the bike sat for a while? Is this happening after the bike sits for a while?

I’m liking Blue’s suggestion of the vacuum-operated valve on the fuel petcock going bad. You can confirm that by turning the petcock to “Off” immediately after shutting off the bike. If the carb(s) stop leaking after that, then you know you need to replace or rebuild the petcock.
(Are rebuild kits available for these petcocks?).

even with no petcock and constant fuel provided to the carbs, properly working float valves regulate the level of fuel inside the carbs. for it to leak out like that while it is off, it needs to go past the petcock and the float valves. the float valves are not properly controlling the level in the carbs. that is the primary problem here. the petcock is secondary but its probably also a good idea to take care of that too huh

even with no petcock and constant fuel provided to the carbs, properly working float valves regulate the level of fuel inside the carbs. for it to leak out like that while it is off, it needs to go past the petcock and the float valves. the float valves are not properly controlling the level in the carbs. that is the primary problem here. the petcock is secondary but its probably also a good idea to take care of that too huh

True. You are correct!

But if the bike is running well, and it only occurs after the bike has been sitting awhile (that is, if it is a really really slow leak at the float-controlled needle valve in the carb, and it otherwise doesn’t adversely affect things when the bike is running)… It’s an excellent philosophical question as to which is the worse problem: the carb needle valve or the vacuum-operated petcock valve.

If it were me, I would first fix the petcock. If there were no further observable problems, I’d let sleeping dogs lie. And the bad needle valve in the carb might clear itself if it was due to a hair or other tiny piece of debris. But we’d never really know because we fixed the petcock. Hmmm. A koan…

Each of us must determine our own level of what imperfections we live with.

True. You are correct!

But if the bike is running well, and it only occurs after the bike has been sitting awhile (that is, if it is a really really slow leak at the float-controlled needle valve in the carb, and it otherwise doesn’t adversely affect things when the bike is running)… It’s an excellent philosophical question as to which is the worse problem: the carb needle valve or the vacuum-operated petcock valve.

If it were me, I would first fix the petcock. If there were no further observable problems, I’d let sleeping dogs lie. And the bad needle valve in the carb might clear itself if it was due to a hair or other tiny piece of debris. But we’d never really know because we fixed the petcock. Hmmm. A koan…

Each of us must determine our own level of what imperfections we live with.

according to OP:

Today, i was as a stop sign and the bike died.


so it would seem that even while running, the floats are flooding the carbs. we know that while the bike is running, the petcock (vacuum operated valve) should be open with fuel free-flowing to the carbs fuel inlet. i'm making the assumption that the two problems are related which they might not be. maybe it actually died because of some CDI issue or some other random thing. but because we only know a limited amount about the situation we gotta make some assumptions right?

about which is more important... if the float valves worked perfectly but the petcock was stuck open, it would not have any issues because the float valves are the main control of the fuel level in the carbs. fuel level would remain correct, and nothing would leak because the carbs are not overflowing.

if the petcock vacuum valve was working correctly but the float valves didn't work, it would not hardly run at all because the fuel level would never be correct. it would either never fill the carbs or simply keep the valve open and flood the carbs. if the petcock worked correctly it should not be leaking while off. (should not be able to supply extra fuel while the vacuum valve is closed)

the float valves are the primary mechanism for controlling fuel height in the carbs. the petcock valve is simply an extra measure to try to put less stress on the float valves while it sits there doing nothing. and fuel height in the carbs is a very important thing for them to work correctly.

The bike stops leaking when i switch the pet cock to off. But i replaced the petcock on it the last time as i had a spare.

The bike leaks even if its off. If i start cranking it and pull the choke then it leaks even more.

I bought a rebuild kit, and replaced the plungers in the carbs. But not anything else. I set the floats and it ran fine for a while.

There was gas all over the crank case and in the oil when i changed the oil. More gas was in the first time this happeed since it sat for a long time in a parking lot when i was at work.

The bike stops leaking when i switch the pet cock to off. But i replaced the petcock on it the last time as i had a spare.

The bike leaks even if its off. If i start cranking it and pull the choke then it leaks even more.

I bought a rebuild kit, and replaced the plungers in the carbs. But not anything else. I set the floats and it ran fine for a while.

There was gas all over the crank case and in the oil when i changed the oil. More gas was in the first time this happeed since it sat for a long time in a parking lot when i was at work.

Alex S is correct! (A tip of the hat).

So have you/will you replace the float valves in the carbs?

The float valves were replaced.

What is the correct height of the floats? 17.5mm?

The float valves were replaced.

What is the correct height of the floats? 17.5mm?

Good question for Alex S.

The reason I suggested checking the petcock was, Op said he adjusted the floats and "the bike rode amazingly well, plenty of power and just railed until it stopped."
He does not mention leaking during the period it ran well.
Also IIRC OP has had an issue with his battery and his CDI as well (replaced it), even though he does not mention it here. This could also be a possible reason for unexplained cut off.

Bummer we're spread out across the country and can't look at or lay hands on the bike.

But way cool we can discuss it real time. Amazing time to be alive!

Its nice to get this much help on a forum. I got some things to work with that is for sure. And luckly racerx is close to me, so he will know exacly what is wrong. But id like to fix it myself and learn in the process :)

What is the correct height of the floats? 17.5mm?

Float Height= 17 +/-2mm (0.67 +/-0.08 in.)

maybe there's nasty stuff in the gas tank and its sending crap through the carbs and gumming up the works... does the bike have a fuel filter?

i would check the gas tank... maybe try washing it out or something?? fresh gas and a carb clean and a fuel filter... the petcock may have been replaced but if it lets it leak when its off, it means its stuck open. so it needs to be fixed

maybe there's nasty stuff in the gas tank and its sending crap through the carbs and gumming up the works... does the bike have a fuel filter?

i would check the gas tank... maybe try washing it out or something?? fresh gas and a carb clean and a fuel filter... the petcock may have been replaced but if it lets it leak when its off, it means its stuck open. so it needs to be fixed

The petcock in the off position does stop the carb from leaking.

I did put fresh gas the last time this happened. I don't have a fuel filter, so this is something i will add to the bike this time.

thank you for the suggestions and i will keep you updated.

The petcock in the off position does stop the carb from leaking.



Scorch, which one of your Ninjas are you talking about? The 2008 & up petcocks have RUN & PRI positions, the pre-gens have ON, OFF & RES.

Scorch, which one of your Ninjas are you talking about? The 2008 & up petcocks have RUN & PRI positions, the pre-gens have ON, OFF & RES.

The 08. When i mean off, is i switch to rotate horizantal position.

apparently the diapgram in the top of the carb is ripped on the edges and im told this is the cause of the problem. I am buying used carbs on ebay and going to install it and hopefully will take care of the issue.

the float bowls were okay and everthing seemed okay.

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this is a view of the carbs and the ripped diaphram

The diaphrams don't look too ripped, and only on the side. Could this be causing it?

Scorch, having the petcock in the run position, gas should not flow. As you know, it should only flow when the engine is running. The diaphragm doesn't look that bad, however if for some reason one or both are getting stuck or not moving properly (leaking), your bike will run like crap starting at 1/4 throttle (approx 3k rpm). I'd revisit your float valves & petcock to make sure it's closing 100% of the time. Also have Burton take a good look at this thread (http://www.ninjette.org/forums/showthread.php?t=44054&highlight=petcock)and a potential petcock defect.

If the carbs are flooding with fuel, and you spin the starter you can hydro lock/bend the rod.

Find the cause of the bowls overflowing and what made the noise in the engine. It might be a doorstop at this point. Torn diaphragm will not cause the fuel over flow.

Describe the noise it made.

I'd start with zero fuel in carbs, and a compression test. Then if OK, tear down the carbs and rebuild everything including the float needle/seat.

The noise it made seems consitent with the hydro lock noise. Or at least what i think it might be. it felt as if the piston got stuck. But then after i cranked it again it cranked fine. Just didnt start.

i ordered a new carb, and will replace it with this one.

The petcock ill have to look into it as well. ill put in the carb and then look into the petcock.

A friend's DRZ did just that, bent the rod and required a full rebuild. Hopefully that isn't the issue but it is possible. You can't get/borrow a compression tester? Try a Auto Zone for a rental/loaner or a simple push in style with the rubber tip, they are cheap.

Pull the tank and the spark plugs. You might as well know what the condition of the engine is. If the rod is bent it should be low on compression. No carb swap will fix that.

Hopefully i wont need a rebuild. I think about 5k miles ago racerx checked my compression and he said it was good. I doubt the compression is bad. If the compression is bad, shouldnt the power of the bike also be bad? Its not the case, the bike has tons of power and rides really well.

Hopefull i can get this bike running. Luckly i have 2 250's to ride.

Hopefully i wont need a rebuild. I think about 5k miles ago racerx checked my compression and he said it was good. I doubt the compression is bad. If the compression is bad, shouldnt the power of the bike also be bad? Its not the case, the bike has tons of power and rides really well.

Hopefull i can get this bike running. Luckly i have 2 250's to ride.

If the noise you heard was a failure of a part, your compression could have been great just before that but would be bad now. What is was 5k miles before is not important, but nice to know. What it is now is relevant to your issues and how to proceed. You may have a cracked piston, a bent valve or rod, jumped timing? A comp test will tell you if there is a failure in the top end.

I bought a set of carbs from ebay. Got them yesterdaay, and today i installed it. The bike started up no prob. But now i realize that a few pieces are missing from the carb. a screw holding the top, and a cable for the choke.

The bike has started, but again it started befoe after i adjusted the valves. Hopefully there is something up with the other carb and wont do this again.

Ill keep you guys updated, still got a day or so of work putting it together.

I also changed the oil, the oil was super clean.

So i put on the new carb and it didnt work. It only worked when it was on full choke.

Then burton told me to clean the main jets etc.. I took it apart and put the main jet and pilot jet etc.. from the old carb and into the new one.

After putting it together it started up. still was not running right. But now when i gave it throttle it would not die which was good. Adjusted the idle and now it idles perfectly.

So hopefully ill ride her tommorow and it wont spew gas anymore. Ill keep everyone posted.

How many miles that thing got now?

Ive been stuck at 80,000 . I think i only put 4k miles on it last year because of these probs.

80K on an 08. that's an impressive number of miles... I only have 55K on the car I purchased in 2009.

Ive been stuck at 80,000 . I think i only put 4k miles on it last year because of these probs.

Same original engine?

Still the same engine. But with the problems with the fuel leaking etc... i might be shopping around for a new engine soon enough. I hope i can get a few more miles out of this one.

Here is a video of theninja with a new carb and new manuam cam tensioner installed.

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