Running on one cylinder. Not electrical?

Kygirl · May 13th, 2012, 02:02 PM

Just like the title says, my 08 ninja is only running on one cylinder. The plug looks good (light brown, not wet or oily or carbon fouled) and has good spark when laid on the cylinder head with the bike running, so I think the plug, plug wire, and coil are ok. Carbs were just taken out last month and were clean. There is gas in the bowl of the non working side. I pulled the air filter out and it looks good and clean, can't see anything blocking air from the airbox side. Any other ideas or anything else to check before I take the carbs out again?

Bueller999 · May 13th, 2012, 03:58 PM

the diaphragm on the non running side is leaking, I had this problem when I pulled my slide one time. Small spot in sealing surface was leaking air.

LoD575 · May 13th, 2012, 09:14 PM

If the plug is not wet means no fuel is entering the cylinder.

Diagphram is a good place to start.

alex.s · May 14th, 2012, 01:07 PM

not sure why you think its the diaphram but you can check it by raising the floats all the way and releasing them. if one falls faster, its broken

might want to check compression

Kygirl · May 15th, 2012, 01:38 PM

Thanks for the help! I pulled the carbs and the floats seem to be fine and there are no holes or tears in the diaphragm. It also seemed to be seated/sealed well, but I guess I won't know for sure til I put them back in? Compression is good. Nothing jumps out or is obviously wrong. Going to check the jets to make sure they aren't clogged. Anything else you can think of? I appreciate the help!

alex.s · May 15th, 2012, 01:45 PM

this might be a silly question but are you sure its not firing?
maybe the carbs are so far out of sync the one carb is completely off?
does the cylinder fire with WOT? does it ever fire?

Kygirl · May 16th, 2012, 12:50 PM

I just synchronized the carbs with a Pro motion mercury stick sync tool about a month ago so they should have still been in sync. I took them out, no visible problems, put them back in, and now it runs on both cylinders. I'm still not completely sure why, but it works. Only thing I can think is that there was some small obstruction that I dislodged, or an airleak I didn't see that I resolved when I put the back in. Thanks for all the help guys!

May 13th, 2012, 02:02 PM	#1
Kygirl ninjette.org member Name: Sarah Location: Kentucky Join Date: Apr 2012 Motorcycle(s): 2008 ninja 250R 1979 SuzukiGS425E Posts: 94	Running on one cylinder. Not electrical? Just like the title says, my 08 ninja is only running on one cylinder. The plug looks good (light brown, not wet or oily or carbon fouled) and has good spark when laid on the cylinder head with the bike running, so I think the plug, plug wire, and coil are ok. Carbs were just taken out last month and were clean. There is gas in the bowl of the non working side. I pulled the air filter out and it looks good and clean, can't see anything blocking air from the airbox side. Any other ideas or anything else to check before I take the carbs out again?

May 13th, 2012, 03:58 PM	#2
Bueller999 Oldie but a goodie Name: David Location: Aurora, CO Join Date: Nov 2010 Motorcycle(s): 08 Ninja 650r, 06 SV 650 race, 08 250r race, 03 Buell XB9s, 01 KTM 300 EXC Posts: 131	the diaphragm on the non running side is leaking, I had this problem when I pulled my slide one time. Small spot in sealing surface was leaking air. __________________________________________________ ABRacing

May 14th, 2012, 01:07 PM	#4
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	not sure why you think its the diaphram but you can check it by raising the floats all the way and releasing them. if one falls faster, its broken might want to check compression __________________________________________________

May 15th, 2012, 01:45 PM	#6
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	this might be a silly question but are you sure its not firing? maybe the carbs are so far out of sync the one carb is completely off? does the cylinder fire with WOT? does it ever fire? __________________________________________________

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May 13th, 2012, 09:14 PM	#3
LoD575 ninjette.org sage Name: Steve Location: Valdosta GA, US Join Date: Jul 2011 Motorcycle(s): 2012 Ninja 250, 2006 Ninja ZX6R-636 Posts: 661	If the plug is not wet means no fuel is entering the cylinder. Diagphram is a good place to start.

May 15th, 2012, 01:38 PM	#5
Kygirl ninjette.org member Name: Sarah Location: Kentucky Join Date: Apr 2012 Motorcycle(s): 2008 ninja 250R 1979 SuzukiGS425E Posts: 94	Thanks for the help! I pulled the carbs and the floats seem to be fine and there are no holes or tears in the diaphragm. It also seemed to be seated/sealed well, but I guess I won't know for sure til I put them back in? Compression is good. Nothing jumps out or is obviously wrong. Going to check the jets to make sure they aren't clogged. Anything else you can think of? I appreciate the help!

May 16th, 2012, 12:50 PM	#7
Kygirl ninjette.org member Name: Sarah Location: Kentucky Join Date: Apr 2012 Motorcycle(s): 2008 ninja 250R 1979 SuzukiGS425E Posts: 94	I just synchronized the carbs with a Pro motion mercury stick sync tool about a month ago so they should have still been in sync. I took them out, no visible problems, put them back in, and now it runs on both cylinders. I'm still not completely sure why, but it works. Only thing I can think is that there was some small obstruction that I dislodged, or an airleak I didn't see that I resolved when I put the back in. Thanks for all the help guys!