Ninjette is having fueling issues

[AncientTV]

I recently bought a 2007 250 for a song because the PO couldn't get it running right, and now, neither can I

As it sits, the carbs are being constantly drowned in gas; the vacuum that actuates the petcock never ceases for whatever reason. I've done the following:

cleaned the carbs (meticulously, several times, and through every hole and jet imaginable)
rebuilt the petcock
checked the float valves
checked my floats
verified floats are at 17mm

Now, I'm not sure what else there is to do. I tested it by putting a little bit of gas in the float bowls and letting the bike idle with the petcock off (no extra fuel), and the bike ran great. Well, it ran great until I then flipped the petcock to ON, at which point it subsequently flooded the float bowls in gas again.

I've tested it by filling the float bowls up to what should be "full", detaching the fuel line from the carbs, and watching the line shoot out a constant stream of gas, even when the floats should be doing their thing and shutting off the vacuum.

I just want to ride the poor thing

edit: Just did a more direct check method. I took the bowls off the carbs with the carbs still on the bike, and as I cranked it, I either let the floats hang open, or I closed them with my hand. In the open position, they flowed fuel perfectly, and in the (supposedly) closed position, it flowed at about half the open rate. Obviously a seal isn't being created properly somewhere, but I have no idea where to check.

[kkim]

your float valve(s) aren't closing properly. take the float valve needles out of the float valve and check the tapered part of the valve for any rough edges. It should be perfectly smooth down the tapered side. Also, make sure you don't have crud/debris holding that valve open. It can also be the seat portion of the valve (where the tapered portion sits), but usually it's one of the two mentioned problems that keep those valves from closing properly.

[AncientTV]

That was my deduction as well, but the rubber stoppers, along with the rest of the carbs, look brand new. I also couldn't see any obvious stoppages in their seats, but I cleaned and compressed-air'd them for good measure. I'll have to check again tomorrow seeing as it's nearly midnight here.

[kkim]

well, to check them, I've connected a fuel source to the carbs and removed the float bowls so you can lift the floats by hand. When raised up, gas should stop running through that float valve. does it? if not, the valve is bad and needs to be replaced.

check the tapered part of the valve needle carefully. even a visual "ring" that you can't feel can cause that valve to leak.

btw, does you petcock operate as it should??? no gas runs out the fuel line with no vacuum applied, correct?

[AncientTV]

Originally Posted by kkim

well, to check them, I've connected a fuel source to the carbs and removed the float bowls so you can lift the floats by hand. When raised up, gas should stop running through that float valve. does it? if not, the valve is bad and needs to be replaced.

Originally Posted by AncientTV

edit: Just did a more direct check method. I took the bowls off the carbs with the carbs still on the bike, and as I cranked it, I either let the floats hang open, or I closed them with my hand. In the open position, they flowed fuel perfectly, and in the (supposedly) closed position, it flowed at about half the open rate. Obviously a seal isn't being created properly somewhere, but I have no idea where to check.

Yup, did that. The weird thing is, (here's another stupid test) I just went out and blew into the fuel line so air was moving into the carbs just as fuel would, and when my carbs were right side up, floats open, air would pass through. If I turned them upside down, floats closed, no air moved at all. I went blue in the face and it was sealed.

Originally Posted by kkim

check the tapered part of the valve needle carefully. even a visual "ring" that you can't feel can cause that valve to leak.

btw, does you petcock operate as it should??? no gas runs out the fuel line with no vacuum applied, correct?

My petcock was dribbling regardless of vacuum, but I already fixed that. The fuel line is dry as a bone if no vacuum is applied.

[kkim]

Originally Posted by AncientTV

Yup, did that. The weird thing is, (here's another stupid test) I just went out and blew into the fuel line so air was moving into the carbs just as fuel would, and when my carbs were right side up, floats open, air would pass through. If I turned them upside down, floats closed, no air moved at all. I went blue in the face and it was sealed.



My petcock was dribbling regardless of vacuum, but I already fixed that. The fuel line is dry as a bone if no vacuum is applied.

well, unless you ride upside down and use air instead of gasoline, I'd say the valve isn't working properly. do both carbs leak like this or only one?

had to be sure about the petcock as a leaky petcock coupled with a leaky needle valve can lead to a bottom end full of gasoline... not a good failure combo to have.

good source for needle valves... cheaper than a dealer.
http://www.jetsrus.com/needle_valve_...ki_street.html

[AncientTV]

Originally Posted by kkim

well, unless you ride upside down and use air instead of gasoline, I'd say the valve isn't working properly. do both carbs leak like this or only one?

Fair enough, I was just trying to emulate the conditions
I believe it's just the one, but that's really something I'll have to wait until tomorrow to test. Living in a crowded neighborhood does not bode well for nighttime maintenance.

Thanks for all the input, I'll make sure to post an update tomorrow morning.

[kkim]

well, I'm gonna be sleeping then, but I'll check for your findings once I'm up.

[AncientTV]

Well, I'm nearly at wits end. I took the bowls and floats off again, carbs still on the bike, and just pushed the valves up with my hand.

The fuel flow stopped /

Put everything back together, and it's doing the same damn thing as before. Too much gas, bogs down, and eventually dies unless I regulate the petcock manually. It looks like only the left one is doing it as well, but I can't tell exactly where the gas is coming out of, so I can't be sure.

[kkim]

try rotating the float needle valves half a turn and see if the fuel flow changes. it could be the taper not seating fully at some positions???

also, you could try swapping the fuel needles and see if the problem follows the needles or stay consistent with the seats.

[AncientTV]

So I think I might have found my problem. I was poking around in my carbs again today, and I went to go take apart the little valve thing on the left hand side of the left carb and found something a little discerning.

This thing:
http://www.bikebandit.com/houseofmot...10043sch452885
#14024, the air cut valve

I'm not exactly sure what the purpose of it is, but when I opened mine up, I found this:


If you can't see it, the spring seat is bent to hell. I have no idea how it happened, but an entire side is lifted up. Could this be the cause of my woes (please say yes)?

[kkim]

I believe that's the COASTING ENRICHER???

http://faq.ninja250.org/wiki/How_a_c...a_Closed_Mouth

[AncientTV]

That headline is intense. If it's bent though, wouldn't that mean it's "open" all the time, and making the bike run hilariously rich all the time, and not just when it needs it?

[kkim]

sorry, can't help you there. never have had to play with one of those before.

what you say makes sense, though. But, what if the bend is there on purpose to preload the spring? is it easy to bend or is like a spring steel sort of material where it keeps it's shape nicely?

[AncientTV]

Originally Posted by kkim

sorry, can't help you there. never have had to play with one of those before.

what you say makes sense, though. But, what if the bend is there on purpose to preload the spring? is it easy to bend or is like a spring steel sort of material where it keeps it's shape nicely?

Agh, it feels super solid. Is there anything I could be cleaning in between the carbs? I've yet to separate the two.
This is me right now

[kkim]

did you try my needle swap trick to troubleshoot?

[AncientTV]

Originally Posted by kkim

did you try my needle swap trick to troubleshoot?

Oh, right. I did, and it still seals while I'm holding it, but not when they're being actuated by the floats. My floats are at 17mm, but could I possibly have to lower the fuel level using them?

[kkim]

Originally Posted by AncientTV

Oh, right. I did, and it still seals while I'm holding it, but not when they're being actuated by the floats. My floats are at 17mm, but could I possibly have to lower the fuel level using them?

both sides do it?

[AncientTV]

Can't tell with the bowls on, but it looks like gas is just dripping from the left one.

[kkim]

you need to remove the bowls to test this. I really think you have a bad float needle jet. It's not passing the test.

[AncientTV]

The marathon thread continues haha, til tomorrow.

[kkim]

Originally Posted by AncientTV

The marathon thread continues haha, til tomorrow.

[AncientTV]

So I'm checking the valves again today, and so far it is looking like they're bad. I've taken them off the floats and, even though I'm holding them there with my hands, the vacuum line continues to sucksucksuck. Not sure what happened with that one fluke a few posts back, but it didn't work this time.

Quick question though. I tried sealing the holes just by putting my fingers over them, and that did diddly squat. Should that've worked, and if so, do I potentially have a leak elsewhere?

edit: As for the brass tubes that the valves seat it, is it possible for those to leak around the edges? I remember when I was cleaning them out, fluid started to seep out around it.

[kkim]

the float valve seats are usually threaded or pressed into the carb body. looking at a parts diagram, it looks like the seats are pressed in on our bikes. I suppose they could leak if not pressed in correctly, but I have never seen this happen before.

May I suggest another test method? Connect the fuel line to the carbs, connect the vacuum gun to the back port on the fuel petcock. as you apply vacuum to the fuel petcock, fuel will flow.

then, test the float valves with actual gas flowing through the carbs. yes, it will get messy while testing one and the other flowing gas out the float valve, but at least this way you are using gas instead of air to test the float valves' ability to stop gas flow. also, if you have a bad seat, you will be able to see it leaking around the edges as you hold the float valve closed.

one other thing... on the float valve itself, the pin that sticks out the back of the needle valve should be spring loaded. are you getting that pin to spring back out after it's been pushed in?

you have a PM.

[AncientTV]

Originally Posted by kkim

May I suggest another test method? Connect the fuel line to the carbs, connect the vacuum gun to the back port on the fuel petcock. as you apply vacuum to the fuel petcock, fuel will flow.

one other thing... on the float valve itself, the pin that sticks out the back of the needle valve should be spring loaded. are you getting that pin to spring back out after it's been pushed in?

Spring pins are good, and it passed this test with flying colors. No gas got passed the valves when they were in the closed position (on the floats, and being held up by me). I got understandably excited and put the bike back together, but it's still being bitchy
The bottom of the left carb is still wet with gas as well.

[kkim]

float level okay? also, you may need to check the floats to see if they still have the proper buoyancy.

[AncientTV]

That's really all it could be now, right? They're at 17mm (if I'm measuring it correctly, float valve seated, float tang just touching the spring but not compressing it). I'll go through all the troubleshooting in the manual.

If not, I'm almost ready to call it quits I'm afraid.

edit: This may be from left-field, but if my carbs are horribly unsynchronized, could that be playing a part in this?

[AncientTV]

Before I let this die, can someone please take a picture of the internals of their coasting enricher? It's the tiny circular piece screwed into the left side of the left carb. It's accessible without having to remove the carbs, and there are just two screws holding the cover on.


Sorry for the crappy picture. The two screws I've circled are the two that hold the cover on.

Careful, there's a decently strong spring that's compressed by the cover, so remove it slowly. All I need to know is if the metal spring seat is supposed to be bent or flat all the way around. A picture would be best though.

Thanks in advance, this would be extremely helpful, seeing as I can't find any pictures of it online.

[kkim]

[AncientTV]

Saw that one, but it doesn't clearly show if mine's abnormal or not :\