ninjette.org - View Single Post - 2007 Ninja 250 dies and wont start when warm

jkv45 · September 19th, 2018, 06:37 AM

What did you set the Idle Mixture screw to? The "factory" settings aren't exactly right. You want to be in the range of 2.5 turns out.

Have you looked at the plug color? That will tell you if it's running way too rich or running out of gas.

Have you tried opening the throttle as you are cranking?

It may be a fuel flow or venting problem also. When it wants to quit, try opening the gas filler and listen for air rushing in. That would tell you it's not venting.

Check the petcock to make sure it flows gas by applying vacuum and watching it flow (with the fuel line disconnected). Also check the condition of the vacuum line to the carb.

Check the condition of the fuel filter located inside the fuel line at the carb as well as the screens inside the tank.

Have you drained the tank? Old or bad gas can cause odd problems. That's usually the first thing I do if I'm unsure about the age or quality of the gas. If someone had dumped "winter gas" into the tank it could cause a "vaporlock" condition as the lines and carbs heat up. Winter blend gas vaporizes easier than summer blend.

I had an old Honda that started and ran fine, but would not run at WOT. Changed the old gas out and it fixed the problem.

September 19th, 2018, 06:37 AM	#5
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	What did you set the Idle Mixture screw to? The "factory" settings aren't exactly right. You want to be in the range of 2.5 turns out. Have you looked at the plug color? That will tell you if it's running way too rich or running out of gas. Have you tried opening the throttle as you are cranking? It may be a fuel flow or venting problem also. When it wants to quit, try opening the gas filler and listen for air rushing in. That would tell you it's not venting. Check the petcock to make sure it flows gas by applying vacuum and watching it flow (with the fuel line disconnected). Also check the condition of the vacuum line to the carb. Check the condition of the fuel filter located inside the fuel line at the carb as well as the screens inside the tank. Have you drained the tank? Old or bad gas can cause odd problems. That's usually the first thing I do if I'm unsure about the age or quality of the gas. If someone had dumped "winter gas" into the tank it could cause a "vaporlock" condition as the lines and carbs heat up. Winter blend gas vaporizes easier than summer blend. I had an old Honda that started and ran fine, but would not run at WOT. Changed the old gas out and it fixed the problem.