96 ninja keeps dying?

rich3389 · April 8th, 2012, 07:25 AM

I bought a 96 ninja 250 w/ 12k miles. It ran perfect for a few days then it would randomly die when warmed up. I had the carb rebuilt and changed the spark plugs and the problem still persists...

Problem: runs fine until warmed up, then will stall at idle, idle is set at 1500-2000 rpms, no amount of throttle will keep it running. And will not start until cooled down.
Also noticed that the left carb seems to leak gas into the head when bike sits a while off, even after the carb rebuild, related problem maybe?

Motofool · April 8th, 2012, 08:39 AM

Welcome to the site!

Did you rebuild the carbs?

Crack open the gas tank after it dies and see if the engine re-starts and works normally.

If so, the tank ventilation is compromised and gas can't flow down.

The second easy thing to do is to verify the level of the fuel inside the bowl of each carb by connecting a transparent hose (U-shape) to the drain nipple, open it and checking the level while the engine is working.

rich3389 · April 8th, 2012, 10:49 AM

Quote:

Originally Posted by Motofool

Welcome to the site!

Did you rebuild the carbs?

Crack open the gas tank after it dies and see if the engine re-starts and works normally.

If so, the tank ventilation is compromised and gas can't flow down.

The second easy thing to do is to verify the level of the fuel inside the bowl of each carb by connecting a transparent hose (U-shape) to the drain nipple, open it and checking the level while the engine is working.

I did rebuild the carbs

I also tried the opening the gas cap trick with no results...

The problem seems to occur once the engine is warmed up, it will start to spit and sputter then die.

Motofool · April 8th, 2012, 07:51 PM

It could also be valves out of adjustment, which changes with temperature.

A mix that is good for a cold engine may be bad after it warms up.

It seems that the mix is over-rich for low rpm's, unless it also happens at higher rpm's.

Are you sure that the choke is fully releasing the carb's plunge when off?

choneofakind · April 8th, 2012, 08:37 PM

Running fine at start-up and then having issues when warm is a classic symptom of rich mix. Also, carb cleanings do wonders on carb'd bikes.

rich3389 · April 9th, 2012, 04:53 PM

UPDATE: I took the bike out today and it seems that if I keep the throttle low, the problem seems to be non existent, it when I give it 60%+ throttle when it starts to hesitate and die.

choneofakind · April 9th, 2012, 05:05 PM

Check your intake for leaks.

basically, at idle, spray various parts of the intake with WD40, and if the idle shoots up momentarily, that part that you just sprayed is sucking in unfiltered air.

April 8th, 2012, 07:25 AM	#1
rich3389 ninjette.org newbie Name: Rich Location: FL Join Date: Mar 2012 Motorcycle(s): Ninja 250 Posts: 9	96 ninja keeps dying? I bought a 96 ninja 250 w/ 12k miles. It ran perfect for a few days then it would randomly die when warmed up. I had the carb rebuilt and changed the spark plugs and the problem still persists... Problem: runs fine until warmed up, then will stall at idle, idle is set at 1500-2000 rpms, no amount of throttle will keep it running. And will not start until cooled down. Also noticed that the left carb seems to leak gas into the head when bike sits a while off, even after the carb rebuild, related problem maybe?

April 8th, 2012, 08:39 AM	#2
Motofool Daily Ninjette rider Name: Hernan Location: Florida Join Date: Mar 2011 Motorcycle(s): 2007 Ninja 250 Posts: A lot. MOTY - 2016, MOTM - Dec '12, Jan '14, Jan '15, May '16	Welcome to the site! Did you rebuild the carbs? Crack open the gas tank after it dies and see if the engine re-starts and works normally. If so, the tank ventilation is compromised and gas can't flow down. The second easy thing to do is to verify the level of the fuel inside the bowl of each carb by connecting a transparent hose (U-shape) to the drain nipple, open it and checking the level while the engine is working. __________________________________________________ *Motofool* *.................................Never ride faster than your guardian angel can fly* "Mankind is composed of two sorts of men — those who love and create, and those who hate and destroy. Love is the bond between men, the way to teach and the center of the world." - José Martí

April 8th, 2012, 07:51 PM	#4
Motofool Daily Ninjette rider Name: Hernan Location: Florida Join Date: Mar 2011 Motorcycle(s): 2007 Ninja 250 Posts: A lot. MOTY - 2016, MOTM - Dec '12, Jan '14, Jan '15, May '16	It could also be valves out of adjustment, which changes with temperature. A mix that is good for a cold engine may be bad after it warms up. It seems that the mix is over-rich for low rpm's, unless it also happens at higher rpm's. Are you sure that the choke is fully releasing the carb's plunge when off? __________________________________________________ *Motofool* *.................................Never ride faster than your guardian angel can fly* "Mankind is composed of two sorts of men — those who love and create, and those who hate and destroy. Love is the bond between men, the way to teach and the center of the world." - José Martí

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April 8th, 2012, 08:37 PM	#5
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Running fine at start-up and then having issues when warm is a classic symptom of rich mix. Also, carb cleanings do wonders on carb'd bikes.

April 9th, 2012, 04:53 PM	#6
rich3389 ninjette.org newbie Name: Rich Location: FL Join Date: Mar 2012 Motorcycle(s): Ninja 250 Posts: 9	UPDATE: I took the bike out today and it seems that if I keep the throttle low, the problem seems to be non existent, it when I give it 60%+ throttle when it starts to hesitate and die.

April 9th, 2012, 05:05 PM	#7
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Check your intake for leaks. basically, at idle, spray various parts of the intake with WD40, and if the idle shoots up momentarily, that part that you just sprayed is sucking in unfiltered air.