Won't start after pulling carbs

Insan3guy · July 14th, 2013, 02:10 PM

I took the airbox and carbs off yesterday to check them, the airbox was dirty as hell but the carbs were nice and clean. I removed the float bowl covers to check them and then put them back on; I didn't touch any of the parts inside.

I also put a new air filter in (old one was nearly completely disintegrated) and put everything back together and went for a ride. I drove 10 miles, came home, stopped the engine and tried to start it again but it wouldn't catch.

Now it won't start, except for one thing: When I turn the petcock to OFF, it starts right up, revs nicely for a couple seconds, and then dies about 4-5 seconds after starting it. Once or twice after doing one of those, it'll catch just a little bit and then die.

I don't know much about engines (yet) and my uncle says it could be that the air filter has too much oil in it (I already got as much as I could possibly get out, out) so I don't know.

Any ideas?

update: I have the gas tank off right now, and every time I let it sit for about 5 minutes it'll do the same thing as turning off the petcock mentioned above

jkv45 · July 14th, 2013, 03:10 PM

Have you tried opening the throttle slightly as you crank it? Did you remove the covers from the idle mixture screws when you had the carbs off? You may need to make an adjustment to the idle mixture or idle speed.

Take the air filter out completely and see if it starts.

Check the vacuum hose to the petcock. Try it on reserve. How much fuel do you have in the tank, and how old is it?

Insan3guy · July 14th, 2013, 04:30 PM

tried opening the throttle 1/4, 1/2, 3/4, and full with no results.
idle mix screws have been set to 2.5 turns as per the instructions here http://faq.ninja250.org/wiki/How_do_...dle_mixture%3F

air filter in or out, no results
fuel in the tank is 2 days old, half full
petcock on res/on/off off is the only one that gives any results

update: pic of spark plugs attached

Rollingmenace · July 15th, 2013, 06:30 AM

Looks like it is a little rich to me hard to tell but that's what it looks like I'd throw a new set of plugs in there and see if it will fire...
Also just keep in mind that when you pull and check plugs for spark even a fouled plug will fire outside cylinder... But once under compression it will not fire in cylinder......

jkv45 · July 15th, 2013, 06:45 AM

It's getting too much fuel for some reason - float level is too high, something stuck under the needle, or possibly the slides and diaphragm are hanging-up.

Look inside the carb throats and confirm the slides are sitting down all the way (not running). Take your finger and gently lift them and check that they rise and drop properly.

Also confirm that the enrichener ("choke") isn't stuck or hanging up in the "on" position.

Insan3guy · July 15th, 2013, 11:58 PM

Took off the carbs again, found this clear hose had been melted shut by the exhaust. What does it do/how could it affect the engine?
I also got a pair of new spark plugs (may as well), cr8hsa.

Insan3guy · July 16th, 2013, 09:14 PM

Well, that seemed to fix it. Runs like new, plus a new set of plugs and air filter.

I'm curious though, what purpose does that hose serve? ninja250.org calls it a "fuel overflow"

Rollingmenace · July 16th, 2013, 09:16 PM

The melted hose is just your carb vent.. Just cut the end off that's melted it's basically just an overflow for your carbs... I'd double check everything in the carbs.. Float height.. Air screw .. And jetting to make sure everything is good in there

Rollingmenace · July 16th, 2013, 09:19 PM

I'd deffinitly check your jetting and float height.. There is a reason those plugs are so black

Insan3guy · July 16th, 2013, 09:26 PM

Did all of that while I had them off the bike. clean as a whistle.

jkv45 · July 17th, 2013, 07:12 AM

Good to hear you got it solved!

July 14th, 2013, 02:10 PM	#1
Insan3guy ninjette.org member Name: Patrick Location: Coronado, CA Join Date: Jun 2013 Motorcycle(s): 2015 zx6r Posts: 176	Won't start after pulling carbs (solved!) I took the airbox and carbs off yesterday to check them, the airbox was dirty as hell but the carbs were nice and clean. I removed the float bowl covers to check them and then put them back on; I didn't touch any of the parts inside. I also put a new air filter in (old one was nearly completely disintegrated) and put everything back together and went for a ride. I drove 10 miles, came home, stopped the engine and tried to start it again but it wouldn't catch. Now it won't start, except for one thing: When I turn the petcock to OFF, it starts right up, revs nicely for a couple seconds, and then dies about 4-5 seconds after starting it. Once or twice after doing one of those, it'll catch just a little bit and then die. I don't know much about engines (yet) and my uncle says it could be that the air filter has too much oil in it (I already got as much as I could possibly get out, out) so I don't know. Any ideas? update: I have the gas tank off right now, and every time I let it sit for about 5 minutes it'll do the same thing as turning off the petcock mentioned above Last futzed with by Insan3guy; July 17th, 2013 at 11:21 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Won't start	Espinoza07	1986 - 2007 Ninja 250R Tech Talk	6	September 14th, 2014 08:07 PM
Won't start... :( HELP!	deeno415	1986 - 2007 Ninja 250R Tech Talk	59	August 31st, 2013 05:53 PM
Bike won't start, cleaned carbs, new gas, backfires whats next?	Runeknight95	2008 - 2012 Ninja 250R Tech Talk	7	July 26th, 2013 09:53 PM
2002 Ninja 250 - issues (spark pugs, dirty carbs, won't idle, etc?)	Pocket Sprocket	1986 - 2007 Ninja 250R Tech Talk	12	May 17th, 2013 11:13 AM
Won't start	Momaru	2008 - 2012 Ninja 250R Tech Talk	15	August 9th, 2009 09:48 PM

July 14th, 2013, 03:10 PM	#2
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	Have you tried opening the throttle slightly as you crank it? Did you remove the covers from the idle mixture screws when you had the carbs off? You may need to make an adjustment to the idle mixture or idle speed. Take the air filter out completely and see if it starts. Check the vacuum hose to the petcock. Try it on reserve. How much fuel do you have in the tank, and how old is it?

July 15th, 2013, 06:30 AM	#4
Rollingmenace ninjette.org member Name: Zach Location: Colorado Springs Join Date: Mar 2011 Motorcycle(s): 96 Ninja 250EX , 87 CBR 1000, 86 TRX 260R, 86 KXT 250, 84 ATC 200X, 82 ATC 250R (w/CR480) Posts: 134	Looks like it is a little rich to me hard to tell but that's what it looks like I'd throw a new set of plugs in there and see if it will fire... Also just keep in mind that when you pull and check plugs for spark even a fouled plug will fire outside cylinder... But once under compression it will not fire in cylinder......

July 15th, 2013, 06:45 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	It's getting too much fuel for some reason - float level is too high, something stuck under the needle, or possibly the slides and diaphragm are hanging-up. Look inside the carb throats and confirm the slides are sitting down all the way (not running). Take your finger and gently lift them and check that they rise and drop properly. Also confirm that the enrichener ("choke") isn't stuck or hanging up in the "on" position.

July 16th, 2013, 09:14 PM	#7
Insan3guy ninjette.org member Name: Patrick Location: Coronado, CA Join Date: Jun 2013 Motorcycle(s): 2015 zx6r Posts: 176	Well, that seemed to fix it. Runs like new, plus a new set of plugs and air filter. I'm curious though, what purpose does that hose serve? ninja250.org calls it a "fuel overflow"

July 16th, 2013, 09:16 PM	#8
Rollingmenace ninjette.org member Name: Zach Location: Colorado Springs Join Date: Mar 2011 Motorcycle(s): 96 Ninja 250EX , 87 CBR 1000, 86 TRX 260R, 86 KXT 250, 84 ATC 200X, 82 ATC 250R (w/CR480) Posts: 134	The melted hose is just your carb vent.. Just cut the end off that's melted it's basically just an overflow for your carbs... I'd double check everything in the carbs.. Float height.. Air screw .. And jetting to make sure everything is good in there

July 16th, 2013, 09:19 PM	#9
Rollingmenace ninjette.org member Name: Zach Location: Colorado Springs Join Date: Mar 2011 Motorcycle(s): 96 Ninja 250EX , 87 CBR 1000, 86 TRX 260R, 86 KXT 250, 84 ATC 200X, 82 ATC 250R (w/CR480) Posts: 134	I'd deffinitly check your jetting and float height.. There is a reason those plugs are so black

July 16th, 2013, 09:26 PM	#10
Insan3guy ninjette.org member Name: Patrick Location: Coronado, CA Join Date: Jun 2013 Motorcycle(s): 2015 zx6r Posts: 176	Did all of that while I had them off the bike. clean as a whistle.

July 17th, 2013, 07:12 AM	#11
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	Good to hear you got it solved!