2004 250R Burning Through Gasoline

madmaxjb · August 26th, 2024, 04:37 PM

Hello all,

My 2004 Ninja 250R is getting about 30MPG, which is odd because it is supposed to get 60MPG. I replaced the carburetor recently with one from Amazon, and I believe the jets were size 125 in that carb, when the default jets are 105. Would that really reduce the MPG that much? That would be the only thing I can think of. Also, could I adjust the fuel mixture screws instead of replacing the jets? Thank you guys.

Triple Jim · August 26th, 2024, 05:25 PM

Once you install aftermarket carburetors, all bets are off. The jet numbers are not the same as real Keihin jets, and I'm sure there are other non-trivial differences.

But yes, small differences in jet sizes can make significant changes in fuel consumption. Since most fuel is used at mid-throttle, it's likely that your needles and needle jets are at fault.

Only the idle mixture is adjustable with screws.

madmaxjb · August 26th, 2024, 07:44 PM

Quote:

Originally Posted by Triple Jim

Once you install aftermarket carburetors, all bets are off. The jet numbers are not the same as real Keihin jets, and I'm sure there are other non-trivial differences.

But yes, small differences in jet sizes can make significant changes in fuel consumption. Since most fuel is used at mid-throttle, it's likely that your needles and needle jets are at fault.

Only the idle mixture is adjustable with screws.

Alright, I'll look into replacing the jets, thanks.

Triple Jim · August 27th, 2024, 05:25 AM

Quote:

Originally Posted by madmaxjb

Alright, I'll look into replacing the jets, thanks.

I have a feeling that getting stock needles and needle jets into aftermarket carbs is not going to be easy. If you have the original carbs it would probably be best to get them into decent condition.

ducatiman · August 27th, 2024, 07:59 AM

"aftermarket" carbs are a great unknown.....agree a resto of the original carbset is the wtg.

August 26th, 2024, 04:37 PM	#1
madmaxjb ninjette.org newbie Name: Maximus Location: Florida Join Date: Aug 2024 Motorcycle(s): 2004 Ninja 250 Posts: 4	2004 250R Burning Through Gasoline Hello all, My 2004 Ninja 250R is getting about 30MPG, which is odd because it is supposed to get 60MPG. I replaced the carburetor recently with one from Amazon, and I believe the jets were size 125 in that carb, when the default jets are 105. Would that really reduce the MPG that much? That would be the only thing I can think of. Also, could I adjust the fuel mixture screws instead of replacing the jets? Thank you guys.

August 27th, 2024, 07:59 AM	#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	"aftermarket" carbs are a great unknown.....agree a resto of the original carbset is the wtg. __________________________________________________ Custom Carb Service
	1 out of 1 members found this post helpful.

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August 26th, 2024, 05:25 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	Once you install aftermarket carburetors, all bets are off. The jet numbers are not the same as real Keihin jets, and I'm sure there are other non-trivial differences. But yes, small differences in jet sizes can make significant changes in fuel consumption. Since most fuel is used at mid-throttle, it's likely that your needles and needle jets are at fault. Only the idle mixture is adjustable with screws.