Ninja starting issue and throttle issue

Ryan Small · January 1st, 2024, 11:42 AM

Hi all, this is my first post on here. I have a 2010 ninja 250r I bought as a project. It did t run when I got it so I took the carbs apart, replaced hers with new OEM ones and put a fresh battery in the bike. Reassembled everything and now she runs. It’s tough to start and sometime takes sone starter fluid to get going but once it’s running it idles well. The carbs are clean but when I twist the throttle I have to do so slowly or it will big and die. It also seems to stick a little and slowly return to idle. It seems as though it’s running too lean. Do I have to pull the carbs off to adjust the idle mixture screws or is there a way to do this while on the bike? I’ve heard they have caps on them but haven’t taken a look on my own yet! I have attached a video below.

Thanks in advance!

trim.53350DF2-40E2-4A4A-942D-C85B89CAF3DD.MOV

Triple Jim · January 1st, 2024, 12:41 PM

Hi Ryan, welcome! @ducatiman should be along shortly. He's the go-to carb guy here.

Until then, this page might help. In the first sentence it has a link to uncovering the idle mixture screws.

https://faq.ninja250.org/wiki/How_do...dle_mixture%3F

ducatiman · January 1st, 2024, 04:06 PM

I'd be concerned with idle jets/passages being totally clean.

I opt to drill the EPA caps, followed by levering them out. Just use care to not create damage where it doesn't exist. Note carb idle screws (caps removed) can be adjusted while installed, however some bodywork may need removal prior.

Best o' luck, just post if any further info needed.

Ryan Small · January 2nd, 2024, 11:57 AM

Sounds good, I was hoping I wouldn’t have to pull the carbs again but ohh well. At least I got lots of winter months still! I’ll pull them drill the caps and then reinstall. Also should have noted I shimmed the needles up two washers so that may have thrown off the air fuel ratio. The other thing I didn’t realize till after as well was that the needles in the left and right carb were different so I’ll try to make sure I install those in the proper carbs. Thanks for all the help @ducatiman I’ll try to update in a few weeks!

ducatiman · January 2nd, 2024, 02:38 PM

factory needle placement as such.................. N9VU in left carb and N9VW needles in right carb, they are lightly marked up at the top of each needle

Triple Jim · January 2nd, 2024, 04:03 PM

Just for reference, when I got Ducatiman to restore my carbs to new condition, the bike immediately ran like new with no needle shims and all stock jets. All I had to do was adjust the idle mixture a little.

January 1st, 2024, 11:42 AM	#1
Ryan Small ninjette.org newbie Name: Ryan Location: Canada Join Date: Jan 2024 Motorcycle(s): Ninja 250, KX 250f Posts: 6	Ninja starting issue and throttle issue Hi all, this is my first post on here. I have a 2010 ninja 250r I bought as a project. It did t run when I got it so I took the carbs apart, replaced hers with new OEM ones and put a fresh battery in the bike. Reassembled everything and now she runs. It’s tough to start and sometime takes sone starter fluid to get going but once it’s running it idles well. The carbs are clean but when I twist the throttle I have to do so slowly or it will big and die. It also seems to stick a little and slowly return to idle. It seems as though it’s running too lean. Do I have to pull the carbs off to adjust the idle mixture screws or is there a way to do this while on the bike? I’ve heard they have caps on them but haven’t taken a look on my own yet! I have attached a video below. Thanks in advance! trim.53350DF2-40E2-4A4A-942D-C85B89CAF3DD.MOV

January 1st, 2024, 04:06 PM	#3
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	I'd be concerned with idle jets/passages being totally clean. I opt to drill the EPA caps, followed by levering them out. Just use care to not create damage where it doesn't exist. Note carb idle screws (caps removed) can be adjusted while installed, however some bodywork may need removal prior. Best o' luck, just post if any further info needed. __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com

January 2nd, 2024, 02:38 PM	#5
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	factory needle placement as such.................. N9VU in left carb and N9VW needles in right carb, they are lightly marked up at the top of each needle __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com

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January 1st, 2024, 12:41 PM	#2
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	Hi Ryan, welcome! @ducatiman should be along shortly. He's the go-to carb guy here. Until then, this page might help. In the first sentence it has a link to uncovering the idle mixture screws. https://faq.ninja250.org/wiki/How_do...dle_mixture%3F

January 2nd, 2024, 11:57 AM	#4
Ryan Small ninjette.org newbie Name: Ryan Location: Canada Join Date: Jan 2024 Motorcycle(s): Ninja 250, KX 250f Posts: 6	Sounds good, I was hoping I wouldn’t have to pull the carbs again but ohh well. At least I got lots of winter months still! I’ll pull them drill the caps and then reinstall. Also should have noted I shimmed the needles up two washers so that may have thrown off the air fuel ratio. The other thing I didn’t realize till after as well was that the needles in the left and right carb were different so I’ll try to make sure I install those in the proper carbs. Thanks for all the help @ducatiman I’ll try to update in a few weeks!

January 2nd, 2024, 04:03 PM	#6
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	Just for reference, when I got Ducatiman to restore my carbs to new condition, the bike immediately ran like new with no needle shims and all stock jets. All I had to do was adjust the idle mixture a little.