Ninja dying at idle / dying when throttle / trouble starting

[heatdeath]

Hi everyone, I just bought a 05 ninja 250 with 6300 miles on it. Rode it the first 100 miles fine. It started dying at idle at stop lights, and then would have trouble starting or not start at all. I did a couple of things: brand new battery, carb refurbish/clean by a professional with high tech ultrasound equip with new rubber parts, new spark plugs, oil/oil filter change, adjusted the clutch cable because it had too much slack, fresh 89 octane gas.

After I replaced/fixed these things I am still having issues:

It takes ~7-10 seconds of me holding down the starter button before the engine kicks in and takes over (with choke all the way on), I'm afraid if this continues Ill blow my starter.

When it finally turns over it revs to 5K RPM, seems a little high.

It has a tendency to die as I pull in clutch and roll off throttle to downshift and come to a stop. When I try to get it going again, it will only go with choke all the way on, even though it should be warm enough (after 5 minutes of riding), and then I started having the problem where I get it to start, pull the clutch out while giving it throttle and the RPM tanks and dies. So I try it in neutral, give it throttle and it dies again. This problem will continue until I eventually flood my engine/carbs and give up.

If that doesnt happen, my bike usually idles at 2K, but will slowly drop until it dies, and I have to blip the throttle at idle to make sure it wont die.

Any ideas would be much appreciating, I am at the end of my rope.

[Ram Jet]

Originally Posted by heatdeath

Hi everyone, I just bought a 05 ninja 250 with 6300 miles on it. Rode it the first 100 miles fine. It started dying at idle at stop lights, and then would have trouble starting or not start at all. I did a couple of things: brand new battery, carb refurbish/clean by a professional with high tech ultrasound equip with new rubber parts, new spark plugs, oil/oil filter change, adjusted the clutch cable because it had too much slack, fresh 89 octane gas.

After I replaced/fixed these things I am still having issues:

It takes ~7-10 seconds of me holding down the starter button before the engine kicks in and takes over (with choke all the way on), I'm afraid if this continues Ill blow my starter.

When it finally turns over it revs to 5K RPM, seems a little high.



It has a tendency to die as I pull in clutch and roll off throttle to downshift and come to a stop. When I try to get it going again, it will only go with choke all the way on, even though it should be warm enough (after 5 minutes of riding), and then I started having the problem where I get it to start, pull the clutch out while giving it throttle and the RPM tanks and dies. So I try it in neutral, give it throttle and it dies again. This problem will continue until I eventually flood my engine/carbs and give up.

If that doesnt happen, my bike usually idles at 2K, but will slowly drop until it dies, and I have to blip the throttle at idle to make sure it wont die.

Any ideas would be much appreciating, I am at the end of my rope.

When your engine starts you should roll back the choke lever a little bit to get it to settle to a 2,000 R,P.M. idle.

You may have a vacuum leak somewhere of a vacuum hose mis-connected.

Bill

[heatdeath]

The bike will start with full choke, rev to 5K. If I pull the choke back half-way or even a quarter it will die... seems like its 5K or nothing, maybe I need to finesse it a little more.

As far as the vacuum goes, the vacuum hose is firmly connected petcock to carb and seems fine. I have a CA bike so the coasting enricher vacuum hose that connects the two carbs also connects to this weird black cylinder that also connects to the tank (my tank has 3 lines coming out of it, rather than 1 which ive seen mostly on the internet for this bike). I dont know what its for, but it is also firmly connected

[spent_too_much]

I have read many times to use 87 octane fuel. Perhaps the 89 is part of the issue?

https://faq.ninja250.org/wiki/What_k...hould_I_use%3F


Are you running out of fuel? Do you have it on reserve? Have you serviced the pet cock?

https://faq.ninja250.org/wiki/Rebuil...tcock/fuel_tap


Have you been able to set the idle adjustment to around 1,500 RPMs?

What about the built in fuel filter ( if it has one )? It is recommended to remove it, and replace it with an aftermarket one.

https://faq.ninja250.org/wiki/How_do...fuel_filter%3F

[heatdeath]

Originally Posted by spent_too_much

I have read many times to use 87 octane fuel. Perhaps the 89 is part of the issue?

https://faq.ninja250.org/wiki/What_k...hould_I_use%3F


Are you running out of fuel? Do you have it on reserve? Have you serviced the pet cock?

https://faq.ninja250.org/wiki/Rebuil...tcock/fuel_tap


Have you been able to set the idle adjustment to around 1,500 RPMs?

What about the built in fuel filter ( if it has one )? It is recommended to remove it, and replace it with an aftermarket one.

https://faq.ninja250.org/wiki/How_do...fuel_filter%3F

Sorry I meant to say 87 octane gas. It was running fine the other day, but now it wont start at all so I cannot adjust the idle. I am not sure if the petcock is the problem because it was running fine, but now it isnt. I check the fuel line and there is fuel in there so I'm assuming the petcock is at least allowing fuel to pass. Also checked the filter and it is clean.

[Ram Jet]

Originally Posted by heatdeath

Sorry I meant to say 87 octane gas. It was running fine the other day, but now it wont start at all so I cannot adjust the idle. I am not sure if the petcock is the problem because it was running fine, but now it isnt. I check the fuel line and there is fuel in there so I'm assuming the petcock is at least allowing fuel to pass. Also checked the filter and it is clean.

You might try removing a float bowl drain screw. Drain the carburetor and crank the engine over to see if fuel runs out of the float bowl drain wnile it's turning over. At least you'll know if fuel is getting to the carburetors.

Bill

[jkv45]

It may be worth draining the tank completely and refilling with fresh gas. If there was any old gas or condensation in the tank, adding fresh on top of it isn't going to make it better.

Did you check all of the electrical connections, battery voltage, and grounds?

[DannoXYZ]

Bill’s onto something here! Yes, test fuel flow to carbs.

I had this exact problem on my race bike last year. Took a lot of cranking to start. Would die at low-speeds or idling. Turned out I had a kinked vacuum hose going to petcock. It would only let enough vacuum through when engine was revving. At low speeds and idle, kink would limit vacuum and petcock would close up. Leading to dying engine within 20-30 seconds.

[Ghostt]

Could also be a bad fuel shutoff, is there a fuel filter in use?

[heatdeath]

Originally Posted by JacRyann

Bill’s onto something here! Yes, test fuel flow to carbs.

I had this exact problem on my race bike last year. Took a lot of cranking to start. Would die at low-speeds or idling. Turned out I had a kinked vacuum hose going to petcock. It would only let enough vacuum through when engine was revving. At low speeds and idle, kink would limit vacuum and petcock would close up. Leading to dying engine within 20-30 seconds.

Yes I just did what Bill suggested. Even though the bike was running before, it seems now there is no fuel going to the carbs (opened the drains and cranked it, nothing came out), also no fuel in the fuel line to the carb. The inline fuel filter is clean as a whistle.

The vacuum line looks fine but Ill go ahead and replace it anyway.

I checked my battery and it is reading 12.8 Volts before cranking, and about 11.xx volts while cranking. I checked all my fuses and they are intact, and followed the connections, everything seems proper. There is a little corrosion/rust over a bolt connecting to the 30 Amp fuse. Before my bike broke down, I thought it was my battery that wasnt holding a charge (before I replaced the battery in my multimeter and actually checked it), because my friend was following me and he said that my tail light was flickering. My battery was good thou, to be sure I hooked it up to a brand new one but it still wouldnt start (but maybe because of the issue of getting fuel to the carbs).

[jkv45]

Originally Posted by heatdeath

Yes I just did what Bill suggested. Even though the bike was running before, it seems now there is no fuel going to the carbs (opened the drains and cranked it, nothing came out), also no fuel in the fuel line to the carb. The inline fuel filter is clean as a whistle.

Disconnect the fuel line from the carbs, open the fuel filler on the tank, and apply vacuum to the petcock. Be ready to catch the gas. If it doesn't flow you know you have an issue with the petcock not opening under vacuum.

[heatdeath]

Originally Posted by jkv45

Disconnect the fuel line from the carbs, open the fuel filler on the tank, and apply vacuum to the petcock. Be ready to catch the gas. If it doesn't flow you know you have an issue with the petcock not opening under vacuum.

How do I apply a vacuum to the petcock? Would a siphon rig work?

[Ram Jet]

Originally Posted by heatdeath

How do I apply a vacuum to the petcock? Would a siphon rig work?

Just hook up a piece of hose to your petcock and draw on it like a soda straw. The petcock doesn't require a-lot of vacuum.

Bill

[ducatiman]

veterinary or human

[Ghostt]

Might I add you only need to apply the vacuum once, if you have to keep the vacuum up, then your petcock is bad, and need to be rebuilt.

[DannoXYZ]

Originally Posted by heatdeath

How do I apply a vacuum to the petcock? Would a siphon rig work?

I use one of these vacuum pump & gauge combos. Really handy for troubleshooting like this because you can connect a T to petcock and measure actual vacuum levels.

1. IF you have low vacuum < 10 in.Hg., vacuum hose is leaking or kinked
2. IF you have high vacuum > 15 in.Hg, but still no fuel-flow, then petcock is bad and not opening enough

Simple diagnosis process with minimal time spent and no replacing of perfectly good parts with brand-new perfectly good parts. Also works great for bleeding brakes too.

[heatdeath]

Originally Posted by Ram Jet

Just hook up a piece of hose to your petcock and draw on it like a soda straw. The petcock doesn't require a-lot of vacuum.

Bill

So I did that and yes, after applying vacuum with petcock in ON position no fuel came out. I tried it with petcock on reserve and fuel did come out. Theoretically I can ride on reserve? Does that mean the whole petcock is broken and I need to get a new one, or something may be clogged that I can just clean it?

[DannoXYZ]

Are you sure you're not low on fuel in tank?

[Ram Jet]

Originally Posted by heatdeath

So I did that and yes, after applying vacuum with petcock in ON position no fuel came out. I tried it with petcock on reserve and fuel did come out. Theoretically I can ride on reserve? Does that mean the whole petcock is broken and I need to get a new one, or something may be clogged that I can just clean it?

The vacuum petcock on my Honda can be rebuilt but I don't know about the Kawasaki. I dumped the vacuum petcock on my Honda and replaced it with a manual. Since the replacement petcock for the Ninja is so expensive I might consider doing the same. On the Honda you simply have to remove the spring on the diaphragm and move it to the opposite side of the diaphragm, cap the vacuum port on the intake manifold and the problem is fixed. I've never had the Kaw petcock apart so I don't know if it can be done on the Ninja. You might be able to disassemble the petcock and clean it.

Bill

[heatdeath]

The bike runs fine on reserve. I guess the issue is the petcock. I just took it on a spin and there was no dying at idle. I sprayed some carb cleaner around the boots/carb/vac lines to see if there was any change in the tach, and there was not, so the vac issue must be happening in the petcock. Im still not sure about why my taillight was flickering that day when my friend followed me, the battery is fine and connections look good. Ill have him follow me again later when it gets dark to see if it still is happening, i dont know how it could be related to the petcock but we'll see.

[spent_too_much]

Rebuling the petcock is easy. And now, there is one kit that contains all of the parts. I did it myself in this thread. Post #16.

https://www.ninjette.org/forums/showthread.php?t=271929

Instructions here:
http://faq.ninja250.org/wiki/Rebuild...tcock/fuel_tap

[ducatiman]

Originally Posted by heatdeath

The bike runs fine on reserve. I guess the issue is the petcock. I just took it on a spin and there was no dying at idle. I sprayed some carb cleaner around the boots/carb/vac lines to see if there was any change in the tach, and there was not, so the vac issue must be happening in the petcock. Im still not sure about why my taillight was flickering that day when my friend followed me, the battery is fine and connections look good. Ill have him follow me again later when it gets dark to see if it still is happening, i dont know how it could be related to the petcock but we'll see.

Yaaaaay!

The petcock problem is on the delivery side (front end) ...not the vacuum side (back end).

Regardless, will need eventual removal, disassembly, cleaning, new oring and valve rubber. Good idea to have the parts on hand before going forward.

[Triple Jim]

Originally Posted by Ghostt

Might I add you only need to apply the vacuum once, if you have to keep the vacuum up, then your petcock is bad, and need to be rebuilt.

I'm probably misunderstanding you, but as soon as vacuum is released, the petcock will close. Maybe you mean that if you have to keep moving the syringe's plunger, for example, the diaphragm has a leak.

[Ghostt]

Originally Posted by Triple Jim

I'm probably misunderstanding you, but as soon as vacuum is released, the petcock will close. Maybe you mean that if you have to keep moving the syringe's plunger, for example, the diaphragm has a leak.

Yes, if you need to keep applying the vacuum, then the diaphragm is bad. I had this happen to Serenity last season, as I was testing the petcock with my hand vacuum pump, I noticed the vacuum gauge dropped. Ordered the rebuilding kit, problem solved.

UPDATE by Ghostt: K&L SUPPLY now makes a complete kit for 88-07 models, according to their own 2016 catalog, Part # 18-2702.

[heatdeath]

I found a cheap new petcock on ebay ~$50, replaced it on the tank and the bike fired right up, ive put 400 miles on it since. Thanks guys for all the help!

[Ghostt]

Glad to hear that

[ducatiman]

me too

petcock failures are quite common on these