Thread: Carb woes
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Old July 1st, 2021, 09:35 PM   #1
marshallsmith27
ninjette.org member
 
Name: Marshall
Location: Tuscaloosa, AL
Join Date: Jun 2021

Motorcycle(s): 2007 Ninja 250 and 2006 Triumph America

Posts: 171
Carb woes

To start I pulled this bike out from under the tarp it's been under for the last 8 years or so put a jump box on the battery leads and sprayed some ether and it turned over instantly. I was excited so I pulled the carbs off and spent half the day getting them absolutely spotless. I then ordered all new o-rings and gaskets. Someone almost hit me 8 years ago and I had no choice but to ride down into a deep holler and it really uglied up the fairings and popped the rear tire. The bike never ran very well before so I just put it up. It was a hit and miss if it would ever start before the wreck anyway.

So I have currently:

•110 Mains (Genuine Keihin Jets) 115 was too rich
•38 idle (Stock) also tried genuine 42 idle jets but that made no difference
•All 5 vacuum nipples on the carbs capped
•Carb bodies in sync
•Stock needles but have shimmed to 1mm, 2mm, 3mm trying to even the idle
•2 Brand new float valves
•Floats set to 17mm
•Tried 2 to 5 turns on the AF screw
•Removed the enricher/tried it with the enricher. ran worse with the enricher and it is in good condition
•Running it currently off of an auxiliary fuel bottle. shouldn't make a difference since the vacuum ports are capped with actual vacuum caps
•It's firing on both cylinders

It revs fine but its the return to idle and the actual consistent idle that is SO bad.


It starts up and runs but surges soon as you give it gas and then takes forever to return to idle which it rarely returns to a nice consistent idle. usually returns to around 500 rpm and nearly dies.

The intake boots are not cracked. I am running velocity stacks on it right now so thats one of the reasons I tried the 115 jets was to see if I could match all the extra air coming in.


The only other things I can think of is that it doesn't like running off of the jump box which it seems to not mind the jump box, theres something wrong with the igniter which I doubt or the carbs being tuned more sporty like this doesn't work with the stock exhaust?

The surging of the rpms seems like a lean thing (but how could it be lean with 110/42 jets? or a vacuum leak. I sprayed starter fluid all over the carbs and intake boots and nothing happened so I don't think it's that.

Help me out here please!

What am I missing here?
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