EX250 shuts off at highway speeds.

[BlueGirl]

I recently bought a 2003 Ninja 250, California model, with 840 original miles. It has been sitting up for about 8 years. Starting this baby up has been loads of fun. The carbs were gummed up, gas tank was rusted out, fuel petcock was a goner.

Carbs have been cleaned twice and lightly tuned, gas tank derusted, petcock replaced, spark plugs changed twice, the air box has been knocked out and replaced with a K&N air filter. After some trials, it's up and running enough to try taking it out for a ride longer than around the block.

The most current issue (on the second ride out, yesterday), the engine cuts off while at highway speeds. It won't restart once it's cut off. It's running lean-ish, but was running really well after the carbs were lightly tuned. It died on the highway after the tune. After about an hour it cranked fine, and after 2 more miles down the road, it died again. It took about another hour and a half, and a rolling start, to get it cranked again.

We're not entirely sure if it is running lean or not. It ran fine before the air box was taken out. It ran better after it was tuned. We're not sure what is wrong. We haven't dug into it yet since it died

Suggestions?

[Alex]

Did you try popping the tank cap open when starting? If it immediately starts at that point, it could be a clogged tank vent line, causing a vacuum and not allowing the carb bowls to refill.

[thisisbenji]

It still amazes me that people have so much money to blow that they can buy a vehicle and then just let it sit in the garage until it's no good.

Anyways, best of luck with your little Ninja.

[Motofool]

Originally Posted by BlueGirl

.......Suggestions?

Welcome to Ninjette.org, Jessica !!!

Tell us more about you.

It seems to me that what you believe that is clean and functional is not.

Don't use the bike in traffic until is working properly; it is extremely dangerous otherwise.

[BlueGirl]

Originally Posted by Alex

Did you try popping the tank cap open when starting? If it immediately starts at that point, it could be a clogged tank vent line, causing a vacuum and not allowing the carb bowls to refill.

It's been ridden about three or four times at much longer distances, so unlikely to be a line. This new issue came directly after shimming the needle and backing out the pilot screws on the carbs. It was ridden for about 20 minutes, at 90+ mph, when it cut off.

[jkv45]

Originally Posted by BlueGirl

It's been ridden about three or four times at much longer distances, so unlikely to be a line. This new issue came directly after shimming the needle and backing out the pilot screws on the carbs. It was ridden for about 20 minutes, at 90+ mph, when it cut off.

As noted, check for a vacuum issue with the gas tank. Running wide-open, or close to it, for that long would require the tank to vent freely.

The Ninja may use some oil (into the airbox) when run hard for extended periods, so look at the airbox and see what it looks like.

Make sure to keep an eye on the oil level if you are consistently running in that range.

[BlueGirl]

Originally Posted by jkv45

As noted, check for a vacuum issue with the gas tank. Running wide-open, or close to it, for that long would require the tank to vent freely.

The Ninja may use some oil (into the airbox) when run hard for extended periods, so look at the airbox and see what it looks like.

Make sure to keep an eye on the oil level if you are consistently running in that range.

There is no airbox. It was yanked out and a K&N R-0990 was installed in its place.

Oil level seems fine. There is no consistency with this bike yet. It gets run around the corner, it gets run an hour away. A handful of rides and every time something else crops up. The first shut down required a spark plug change, they melted. This second shut down we can't figure out. I will have the vacuum checked again, but we don't believe that is it.

[JasonJ]

if your plugs melted, you must be running very lean.. that takes a lot of heat to melt a plug.

I would revert it as much as possible back to stock.. factory settings for everything, carbs, airbox, etc.. get it running properly the normal way and THEN start swapping in your mods and parts.

If it is running that lean, perhaps there is an issue with vapor lock where the float bowls are filling with gasoline vapor instead of liquid fuel.. but also, as mentioned twice, pop the fuel cap at the next shutdown and see if perhaps the tank is not venting properly.. that will indeed cause a vacuum condition inside the tank that will prevent any fuel from being delivered down the lines and to the carbs.

[BlueGirl]

Originally Posted by JasonJ

if your plugs melted, you must be running very lean.. that takes a lot of heat to melt a plug.

I would revert it as much as possible back to stock.. factory settings for everything, carbs, airbox, etc.. get it running properly the normal way and THEN start swapping in your mods and parts.

If it is running that lean, perhaps there is an issue with vapor lock where the float bowls are filling with gasoline vapor instead of liquid fuel.. but also, as mentioned twice, pop the fuel cap at the next shutdown and see if perhaps the tank is not venting properly.. that will indeed cause a vacuum condition inside the tank that will prevent any fuel from being delivered down the lines and to the carbs.

The plugs were Champions. They melted because they were the incorrect heat range; found out later that Champion has the incorrect cross reference. The bike started and ran fine after swapping back to the stock NGK plug.

[Hero Danny]

It may be possible that the bike is over heating? Did you by chance glance at the temp gauge?

[BlueGirl]

Originally Posted by Hero Danny

It may be possible that the bike is over heating? Did you by chance glance at the temp gauge?

Temperature gauge said the bike was not overheating at the time.

[DaBlue1]

Originally Posted by BlueGirl

......the air box has been knocked out and replaced with a K&N air filter.

...... It's running lean-ish, but was running really well after the carbs were lightly tuned.

When the airbox was removed, were the main jets changed in size?
What other intake mods do you have on the bike?

If you were/are running lean, you may experience other symptoms.

Typical Lean Conditions:

- Poor acceleration; the engine feels flat.

- The engine won't respond when the throttle is snapped open, but it picks up speed as the throttle is closed. (A too-large main jet also mimics this symptom.)

- The engine runs hot, knocks, pings and overheats.

- The engine surges or hunts when cruising at part-throttle.

- Popping or spitting through the carb occurs when the throttle is opened. Or popping and spitting occurs through the pipe on deceleration with a closed throttle.

- The engine runs better in warm weather, worse in cool.

- Performance gets worse when the air filter is removed.

I'd take a look at your float valves to see if they are properly adjusted and possibly being stuck when the engine shuts off and you have to wait to be able to start it again. Also make sure your fuel lines are plumbed correctly and that you have no impediments such as an improper external fuel filter that can't keep up with fuel flow demand.

[BlueGirl]

Originally Posted by DaBlue1

When the airbox was removed, were the main jets changed in size?
What other intake mods do you have on the bike?

If you were/are running lean, you may experience other symptoms.

Typical Lean Conditions:

- Poor acceleration; the engine feels flat.

- The engine won't respond when the throttle is snapped open, but it picks up speed as the throttle is closed. (A too-large main jet also mimics this symptom.)

- The engine runs hot, knocks, pings and overheats.

- The engine surges or hunts when cruising at part-throttle.

- Popping or spitting through the carb occurs when the throttle is opened. Or popping and spitting occurs through the pipe on deceleration with a closed throttle.

- The engine runs better in warm weather, worse in cool.

- Performance gets worse when the air filter is removed.

I'd take a look at your float valves to see if they are properly adjusted and possibly being stuck when the engine shuts off and you have to wait to be able to start it again. Also make sure your fuel lines are plumbed correctly and that you have no impediments such as an improper external fuel filter that can't keep up with fuel flow demand.

The K&N air filter is the only intake mod at the moment. The jetting has not been changed. The needle was shimmed and the pilot screws were backed out.

We're in the beginnings of a midsouth summer, with temps between 87-93 degrees F and humidity between 60-80%. There is no "cool" right now unless you consider high 70/low 80 cool. Otherwise, after the carbs were adjusted, throttle response seems fine, idle is fine, hasn't run hot since the stock NGK spark plugs were replaced, and does not run any worse at night than during the day. The shut down did occur on the way home, after 7 pm, after the carbs were adjusted.

There is a clear fuel filter on the line between the petcock and the carb, but it is full and allowing fuel to flow. Lines should be plumbed correctly.

[agentbad]

The carbs needs to be jetted for the added airflow of the pod filter like DaBlue1 suggested. 110's with a couple shims seems like a pretty popular setup in the jetting database. I run 112's mains with no shims with that same pod filter and 40 pilots. Fuel screws 2.75 out. At the very least you need to up the main jet size. I used www.jetsrus.com to build my own kit because it's cheaper.

Jetting Database:
https://www.ninjette.org/forums/show...t=jet+database

[DaBlue1]

Originally Posted by BlueGirl

....The K&N air filter is the only intake mod at the moment. The jetting has not been changed. The needle was shimmed and the pilot screws were backed out.

Increasing the main jet size is almost mandatory when going from an airbox to pods. Changing the pilot jet depends on other factors (elevation, exhaust etc) Shimming mainly affects the 1/4 - 3/4 throttle range.

Originally Posted by BlueGirl

....There is a clear fuel filter on the line between the petcock and the carb, but it is full and allowing fuel to flow. Lines should be plumbed correctly.

As long as it looks like this....



and not this....



You should be good.

[BlueGirl]

Originally Posted by DaBlue1

Increasing the main jet size is almost mandatory when going from an airbox to pods. Changing the pilot jet depends on other factors (elevation, exhaust etc) Shimming mainly affects the 1/4 - 3/4 throttle range.




As long as it looks like this....



and not this....



You should be good.

We plan on changing the jets, knew it would be required after tossing the airbox, and we were going to get one of the kits with multiple sizes to play around with and see which the carbs took to best.

It ran okay after the airbox was removed and the K&N was put in, we assumed it was running lean because of the extra air flow, but it was running seemingly without issues. That's when the Champion spark plugs burned out. Replaced them with NGK's and it rode for a 20 minute ride just fine. That was Saturday/Sunday. Monday morning it took an hour ride just fine. Then the carbs were adjusted, it sounded better, and on the second hour ride on Monday, it died after 20 minutes. We don't know if it was the carbs being adjusted without the new jetting that caused it to die, or something else. That's what we're trying to figure out.

My fuel filter looks like both? We have the longer hose (temporarily!) behind the filter going to the carbs because we are taking the tank on and off so much, but the filter is full and with no huge air bubble. I have a Primeline filter on there now as a quick catch for the tank and any crap it had floating around because it was rusted out. I have a Wix to change it out with when it's done settling.

[alex.s]

champions are known to be terrible.

it sounds like you are having fuel supply issues. maybe the tank is building up vacuum or your float valves in the carbs are gummy/stuck. you can confirm it by checking the carb fuel level when its having the issue. it should show low.

its a terrible idea to ride more than a few minutes when it is as lean as you are making it by swapping out the airbox for pods. you are surely overheating your valves. it probably contributed to the champion burning out. this is not a "oh i'll deal with it later" thing. you are doing real damage to your valves. put the airbox back or jet the bike correctly. it could easily be that you are overheating your valves running it at that highway speed up in the rev range where it is much leaner and you are losing compression because of it.

since you probably did damage to the valves running it hot like that you should check your valve clearances.

and no, the water temperature would probably not overheat just because the valves were overheating from a lean fuel flow. so the fact that you haven't seen the temp light go on means nothing.

[jkv45]

I would pull the new plugs and see how they look.

Post a photo and we'll tell you if it looks correct or you need to make mixture adjustments.

Burning up a plug, even if it is the wrong plug, is never a good thing.

[InvisiBill]

It seems pretty common for Kawasaki's tank vents to fail - it's been a fairly common issue on the VN700 and EX500 I've owned. The rubber hardens up and keeps air from flowing properly, causing a vacuum seal in the tank and preventing fuel from properly flowing out to the carbs. It acts just like running out of gas, since the carbs actually do run out of gas, despite the tank being full. The easiest way to check for this condition is to simply pop the cap open when it happens, as already suggested.

I also find it interesting that so many people here suggest adding an external fuel filter instead of using the standard rail filter (49019-1092). The EX500 doesn't come with any filter (other than the petcock screens), and everyone rejoiced when a rail filter was discovered that fit our carbs, so we could get rid of those stupid inline filters that always seemed to cause line routing issues or just have inherent flow problems.

[BlueGirl]

Originally Posted by alex.s

champions are known to be terrible.

it sounds like you are having fuel supply issues. maybe the tank is building up vacuum or your float valves in the carbs are gummy/stuck. you can confirm it by checking the carb fuel level when its having the issue. it should show low.

its a terrible idea to ride more than a few minutes when it is as lean as you are making it by swapping out the airbox for pods. you are surely overheating your valves. it probably contributed to the champion burning out. this is not a "oh i'll deal with it later" thing. you are doing real damage to your valves. put the airbox back or jet the bike correctly. it could easily be that you are overheating your valves running it at that highway speed up in the rev range where it is much leaner and you are losing compression because of it.

since you probably did damage to the valves running it hot like that you should check your valve clearances.

and no, the water temperature would probably not overheat just because the valves were overheating from a lean fuel flow. so the fact that you haven't seen the temp light go on means nothing.

Thank you, I'll have them checked. When the Champions burned out, the fluid wasn't overheated at all. I'm not 100% on the second shutdown, but I don't think it was hot then either, especially since the gauge implied it wasn't over heating.

[BlueGirl]

Originally Posted by InvisiBill

It seems pretty common for Kawasaki's tank vents to fail - it's been a fairly common issue on the VN700 and EX500 I've owned. The rubber hardens up and keeps air from flowing properly, causing a vacuum seal in the tank and preventing fuel from properly flowing out to the carbs. It acts just like running out of gas, since the carbs actually do run out of gas, despite the tank being full. The easiest way to check for this condition is to simply pop the cap open when it happens, as already suggested.

I also find it interesting that so many people here suggest adding an external fuel filter instead of using the standard rail filter (49019-1092). The EX500 doesn't come with any filter (other than the petcock screens), and everyone rejoiced when a rail filter was discovered that fit our carbs, so we could get rid of those stupid inline filters that always seemed to cause line routing issues or just have inherent flow problems.

When I got the bike, the carbs weren't even on it. I got them in a box with the tank and fairing bolts. There was no mini line filter, any where. We checked for it, and decided to use an inline because the petcock was shot. And the gas tank was a total rust bucket. The old gas cap had been pryed off and the tank left open. Im not even sure that the new gas cap that came with the bike when I bought it even properly seals as fuel has spilled out already.

The first time we had it started, we were using fuel out of a universal coolant reservoir. It needed a filter, period. It took three hours to get started the first time. This bike has not been a cake walk, but I knew that when I bought a project.

[BlueGirl]

Originally Posted by InvisiBill

*** BlueGirl, I'm not your mom and I'm not paying for your parts, so do whatever you want with your own bike. ***

Mommy, my bike can end up with the many car engines collectively scattered across my house. It will be rebuilt. It will not be stock. I am looking for solutions to a current problem. Be helpful or bite it.

[Alex]

(I think someone has run into their first [ you ] tag experience)

[BlueGirl]

I need a thumbs up or like button or something..

[InvisiBill]

Originally Posted by Alex

(I think someone has run into their first [ you ] tag experience)

[BlueGirl]

Turns out that one of the pilots does nothing when it is adjusted, no matter which way it is adjusted. The bike needs to idle at 4-5000 rpm's to stay running. Carbs to be completely torn down, soaked, cleaned, and we'll try again.

[agentbad]

Originally Posted by BlueGirl

Turns out that one of the pilots does nothing when it is adjusted, no matter which way it is adjusted. The bike needs to idle at 4-5000 rpm's to stay running. Carbs to be completely torn down, soaked, cleaned, and we'll try again.

When you say pilots you mean fuel mix screws right.

[skrymir69]

I just had this same problem. I ended up rebuilding the carbs 2 times and replacing the petcock. It was dying due to flooding. There was a huge piece of crap under one one the float needles, and both of the rubber o rings on the mixture screws were destroyed. Mine has the stock air filter and 3 turns out seems to be what my bike likes. I am not sure what jets are in mine though. Mines a 2003 cali smog bike also. PO let it rust up also.