Oil rapidly filling airbox, won't run without choke.

44chart · March 28th, 2011, 11:55 AM

Hi everyone!

I am a new member and have read similar posts but need some help. I bought a 2003 Ninja 250 that has not been started for a couple of years. It was winterized and stored with about 5,000 miles on the bike. I drained and filled the tank with new gas, changed the oil, checked the plugs, fluids, gas filter, etc. Bike started pretty easily but would not run without choke. Decided to take it for a ride on a somewhat warm day with the choke on about half way and about half a can of seafoam in the tank. As the engine warmed up oil started to run out of the airbox very rapidly. I immediately went home, still needed choke on. Assuming that the engine was starving for fuel, I checked all the hoses, tank, removed inline fuel filter, and tested petcock. All seemed fine to me. Still had the problem so I pulled the carbs and replaced the main jet, pilot jet, needle, float, and ring gasket. Under the black cover, all looked good. I was careful to reassemble the clean carb correctly. Unfortunately I still cannot run without choke. I disconnected the crankcase overflow from the airbox to watch for oil and as soon as the engine revs at all, oil literally pours out of the hose.

I can't think of anything else to do except test valves, rings etc. I'm not sure how to do that, so would like to see if there is anything else I may have missed before bringing the bike in to the nearest $80 an hour shop. Any suggestions?

Jesse8931 · March 28th, 2011, 12:03 PM

How much oil did you put in the motor sounds like you put way to much

44chart · March 28th, 2011, 12:08 PM

I think I did over fill a little but not more than a half a quart. The problem is, no matter how much I oil I put in, it will literally drain it all out of the overflow hose when the motor is hot.

kkim · March 28th, 2011, 12:10 PM

how are you checking your oil level?

44chart · March 28th, 2011, 12:16 PM

I started out by draining the oil, replaceing the filter, and watching the window on the crankase with the bike sitting level. I had a bottle with 4 quarts of 10w-40 and estimate that the first time, I put in just a little over half (two quarts). I can literally watch two quarts of oil run through the hose in 5 minutes and the little round window goes from full to empty.

Jesse8931 · March 28th, 2011, 12:17 PM

Quote:

Originally Posted by 44chart

I think I did over fill a little but not more than a half a quart. The problem is, no matter how much I oil I put in, it will literally drain it all out of the overflow hose when the motor is hot.

thats alot for that bike. make sure you are holding the bike strait up not on the middle stand and that u look at the sight glass and it is not filling the whole glass.

kkim · March 28th, 2011, 12:20 PM

how does the bike run? starts okay?

have you pulled the plugs?

44chart · March 28th, 2011, 12:26 PM

Bike idles great with choke on about half way, until you twist the throttle. Too much throttle and rpms go down instead of up.

44chart · March 28th, 2011, 12:29 PM

I checked the plugs before the first time running the bike but not since the carb rebuild. Plugs were pretty clean and gapped correctly.

kkim · March 28th, 2011, 12:33 PM

you might have a leaking main crank seal. As far as I know, that's the only way the crankcase can get pressurized enough to push oil out the crankcase overflow tube if you have the correct amount of oil in the engine.

how about your cooling system??? any oil in your radiator or water mixed with your crankcase oil?

44chart · March 28th, 2011, 12:39 PM

You might be right on that. Radiator looks normal but I noticed some light brown bubbly or foamy residue in the leaking oil at first. I wonder if that is coolant. I assumed it was a little gas/blowby mixture. So if that's the case, I would have to pull the jugs. How would I confirm that is the problem?

BTW, thank you so much for your help!

kkim · March 28th, 2011, 12:50 PM

well, if you have coolant in your crankcase oil, I know this seems odd, but count your blessings as it doesn't sound like a leaking crankshaft seal is the problem.

Confirm you coolant leak suspicions by draining and refilling the oil and recheck the oil for continued leaking coolant. Leaking coolant into crankcase will usually make the crank oil look like chocolate milk. If it persists, tracking down the leak source is the next step. Most times it's the head gasket leaking. You might want to try and check the head bolts for proper tightness.

has the bike ever been overheated due to lack of coolant?

DaBlue1 · March 28th, 2011, 01:21 PM

Quote:

Originally Posted by 44chart

I started out by draining the oil, replaceing the filter, and watching the window on the crankase with the bike sitting level. I had a bottle with 4 quarts of 10w-40 and estimate that the first time, I put in just a little over half (two quarts). I can literally watch two quarts of oil run through the hose in 5 minutes and the little round window goes from full to empty.

If the engine is running, you will not see oil in the sight glass. Start with the oil at the lower level of the sight glass with the bike off the center stand.. if your oil if being pushed out the breather tube with force, your oil pump may be clogged or the filter may be clogged. I noticed you said, "I drained and filled the tank with new gas, changed the oil, checked the plugs, fluids, gas filter, etc." Does the etc. include oil filter?
Being that you have an older bike, the last thing would be blowby. You may have some piston ring damage. The piston rings are no longer effectively sealing the combustion chamber. Combustion gases are leaking past them, pressurizing the crankcase. This can cause some problems; seals leak, gaskets fail and, because the pistons are forced to compress the excess air on the downstroke, horsepower can be lost, but not necessarily right away. Checking the cylinder compression will tell you if the rings are bad.
If you are having that much oil come thru the filter, no doubt some of it is being sucked back thru the carbs. If you see whitish or grayish, milky looking foam or film in the oil, oil cap or sight glass, chances are you have a coolant leak or water in the oil.
From what you are saying about throttle response as well as the oil problem would indicate some bad valves, cylinder or ring problems. All of it is definitely something to have looked at by a dealer if you can not do it your self.

choneofakind · March 28th, 2011, 01:36 PM

just a tidbit of info. The manual says the bike needs between 1.6 and 1.9 liters of oil. 1.9 liters = barely less than 2 quarts

44chart · March 28th, 2011, 02:25 PM

Thank you all again for the great tips! The bike has not overheated to the best of my knowledge. Yes I did replace the oil filter, but didn't check the oil pump.

If it is internal, I might swap engines with my parts bike. But it is even older than this one so I would like to rule out all other options before bringing it in for a compression check.

Let me ask this...if there was coolant in the oil, meaning possibly a bad gasket somewhere, would that cause it to only run with the choke on? And stall when opening the throttle?

Also, I've read that when the bike is starving for gas, it will only run with the choke on, which creates pressure in the crank, causing the blowby or oil to shoot up the breather. It would be nice if were as easy as that but I can't seem to find any restricted gas flow.

I guess i'm coming to the conclusion that the first thing to rule out is the rings/low compression. If I can feel good pressure out my exhaust, would that mean my compression is good or do you really need to have it professionally measured?

kkim · March 28th, 2011, 02:31 PM

when you had the carbs apart for cleaning and changed the jets, did you blow/clean out out the passages in the carb body as well???? (the passages the jets screw into)

44chart · March 28th, 2011, 02:40 PM

I just sprayed carb cleaner in the passages, and blew out with compressed air.

kkim · March 28th, 2011, 02:51 PM

and did you get any type of flow through them when you did that?

any smoke out the exhaust when the bike is running?

DaBlue1 · March 28th, 2011, 03:00 PM

Quote:

Originally Posted by 44chart

Let me ask this...if there was coolant in the oil, meaning possibly a bad gasket somewhere, would that cause it to only run with the choke on? And stall when opening the throttle?

Also, I've read that when the bike is starving for gas, it will only run with the choke on, which creates pressure in the crank, causing the blowby or oil to shoot up the breather. It would be nice if were as easy as that but I can't seem to find any restricted gas flow.

I guess i'm coming to the conclusion that the first thing to rule out is the rings/low compression. If I can feel good pressure out my exhaust, would that mean my compression is good or do you really need to have it professionally measured?

Coolant in the oil will not affect the gas in the carb and exhaust pressure is not a measure of compression in the cylinders. They need to be measured.
If your carbs sat up for 2 years, they probably need to be completely taken apart and all the jets cleaned especially the pilot jet. If there was moisture in the cylinders, it is possible you could have some stuck rings. Hard to say without looking though. Getting the carbs in order first, is an easier first step in getting it running right

kkim · March 28th, 2011, 03:05 PM

Quote:

Originally Posted by DaBlue1

Getting the carbs in order first, is an easier first step in getting it running right

I agree. it sounds like you have 2 unrelated problems.

44chart · March 28th, 2011, 09:05 PM

Well I opened up the carb again, blew out everything including every hose. Opened up the needle too 2 1/2 instead of 2. Put it back together. Started it up and it up and after a cloud of smoke and a few sputters it started to run better. After a few minutes it was fixed. Thank you all so much for your help.

kkim · March 28th, 2011, 09:13 PM

glad you got it fixed, but mind telling me what the problem was and what fixed it? I'm confused???

so, it now idles and runs great and you no longer have oil dumping out the crank vent tube?

March 28th, 2011, 11:55 AM	#1
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	Oil rapidly filling airbox, won't run without choke. Hi everyone! I am a new member and have read similar posts but need some help. I bought a 2003 Ninja 250 that has not been started for a couple of years. It was winterized and stored with about 5,000 miles on the bike. I drained and filled the tank with new gas, changed the oil, checked the plugs, fluids, gas filter, etc. Bike started pretty easily but would not run without choke. Decided to take it for a ride on a somewhat warm day with the choke on about half way and about half a can of seafoam in the tank. As the engine warmed up oil started to run out of the airbox very rapidly. I immediately went home, still needed choke on. Assuming that the engine was starving for fuel, I checked all the hoses, tank, removed inline fuel filter, and tested petcock. All seemed fine to me. Still had the problem so I pulled the carbs and replaced the main jet, pilot jet, needle, float, and ring gasket. Under the black cover, all looked good. I was careful to reassemble the clean carb correctly. Unfortunately I still cannot run without choke. I disconnected the crankcase overflow from the airbox to watch for oil and as soon as the engine revs at all, oil literally pours out of the hose. I can't think of anything else to do except test valves, rings etc. I'm not sure how to do that, so would like to see if there is anything else I may have missed before bringing the bike in to the nearest $80 an hour shop. Any suggestions?

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March 28th, 2011, 12:03 PM	#2
Jesse8931 ninjette.org guru Name: Jesse Location: Ann arbor mi Join Date: Mar 2011 Motorcycle(s): 2007 ninja 250r Posts: 374	How much oil did you put in the motor sounds like you put way to much

March 28th, 2011, 12:08 PM	#3
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	I think I did over fill a little but not more than a half a quart. The problem is, no matter how much I oil I put in, it will literally drain it all out of the overflow hose when the motor is hot.

March 28th, 2011, 12:10 PM	#4
kkim Join Date: Nov 2008 Posts: Too much.	how are you checking your oil level?

March 28th, 2011, 12:16 PM	#5
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	I started out by draining the oil, replaceing the filter, and watching the window on the crankase with the bike sitting level. I had a bottle with 4 quarts of 10w-40 and estimate that the first time, I put in just a little over half (two quarts). I can literally watch two quarts of oil run through the hose in 5 minutes and the little round window goes from full to empty.

March 28th, 2011, 12:20 PM	#7
kkim Join Date: Nov 2008 Posts: Too much.	how does the bike run? starts okay? have you pulled the plugs?

March 28th, 2011, 12:26 PM	#8
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	Bike idles great with choke on about half way, until you twist the throttle. Too much throttle and rpms go down instead of up.

March 28th, 2011, 12:29 PM	#9
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	I checked the plugs before the first time running the bike but not since the carb rebuild. Plugs were pretty clean and gapped correctly.

March 28th, 2011, 12:33 PM	#10
kkim Join Date: Nov 2008 Posts: Too much.	you might have a leaking main crank seal. As far as I know, that's the only way the crankcase can get pressurized enough to push oil out the crankcase overflow tube if you have the correct amount of oil in the engine. how about your cooling system??? any oil in your radiator or water mixed with your crankcase oil?

March 28th, 2011, 12:39 PM	#11
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	You might be right on that. Radiator looks normal but I noticed some light brown bubbly or foamy residue in the leaking oil at first. I wonder if that is coolant. I assumed it was a little gas/blowby mixture. So if that's the case, I would have to pull the jugs. How would I confirm that is the problem? BTW, thank you so much for your help!

March 28th, 2011, 12:50 PM	#12
kkim Join Date: Nov 2008 Posts: Too much.	well, if you have coolant in your crankcase oil, I know this seems odd, but count your blessings as it doesn't sound like a leaking crankshaft seal is the problem. Confirm you coolant leak suspicions by draining and refilling the oil and recheck the oil for continued leaking coolant. Leaking coolant into crankcase will usually make the crank oil look like chocolate milk. If it persists, tracking down the leak source is the next step. Most times it's the head gasket leaking. You might want to try and check the head bolts for proper tightness. has the bike ever been overheated due to lack of coolant?

March 28th, 2011, 01:36 PM	#14
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	just a tidbit of info. The manual says the bike needs between 1.6 and 1.9 liters of oil. 1.9 liters = barely less than 2 quarts

March 28th, 2011, 02:25 PM	#15
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	Thank you all again for the great tips! The bike has not overheated to the best of my knowledge. Yes I did replace the oil filter, but didn't check the oil pump. If it is internal, I might swap engines with my parts bike. But it is even older than this one so I would like to rule out all other options before bringing it in for a compression check. Let me ask this...if there was coolant in the oil, meaning possibly a bad gasket somewhere, would that cause it to only run with the choke on? And stall when opening the throttle? Also, I've read that when the bike is starving for gas, it will only run with the choke on, which creates pressure in the crank, causing the blowby or oil to shoot up the breather. It would be nice if were as easy as that but I can't seem to find any restricted gas flow. I guess i'm coming to the conclusion that the first thing to rule out is the rings/low compression. If I can feel good pressure out my exhaust, would that mean my compression is good or do you really need to have it professionally measured?

March 28th, 2011, 02:31 PM	#16
kkim Join Date: Nov 2008 Posts: Too much.	when you had the carbs apart for cleaning and changed the jets, did you blow/clean out out the passages in the carb body as well???? (the passages the jets screw into)

March 28th, 2011, 02:40 PM	#17
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	I just sprayed carb cleaner in the passages, and blew out with compressed air.

March 28th, 2011, 02:51 PM	#18
kkim Join Date: Nov 2008 Posts: Too much.	and did you get any type of flow through them when you did that? any smoke out the exhaust when the bike is running?

March 28th, 2011, 09:05 PM	#21
44chart ninjette.org member Name: Craig Location: White Bear lake MN Join Date: Mar 2011 Motorcycle(s): 2003 Ninja EX250 Posts: 10	Well I opened up the carb again, blew out everything including every hose. Opened up the needle too 2 1/2 instead of 2. Put it back together. Started it up and it up and after a cloud of smoke and a few sputters it started to run better. After a few minutes it was fixed. Thank you all so much for your help.

March 28th, 2011, 09:13 PM	#22
kkim Join Date: Nov 2008 Posts: Too much.	glad you got it fixed, but mind telling me what the problem was and what fixed it? I'm confused??? so, it now idles and runs great and you no longer have oil dumping out the crank vent tube?