ninjette.org - View Single Post - Shimming the Carb Needles... Is it for You?

jkv45 · September 15th, 2016, 02:42 PM

From what you described, I don't think shimming the needles is going to help. Setting the idle mixture screws to 2.5 turns out usually gets you very close, so it's odd that it won't idle decent. How old is the gas? Air filter good?

A couple things you can do before removing the carbs would be to sync them and check for a vacuum leak in the manifolds that connect the carbs to the engine. I might also drain the floatbowls and look at what comes out. If you have condensation in the gas, or it's bad, no amount of adjusting is going to make it run right.

Sounds like you might need to remove the carbs and go through them. The idle circuit (Pilot Jets and passages for the idle mixture screws) may be partially blocked. Cleaning the carb and jets properly isn't easy (read-up on it before you take things apart - http://faq.ninja250.org/wiki/Intake) , but you'll never get it to run right unless everything is spotless and properly adjusted.

September 15th, 2016, 02:42 PM	#83
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	From what you described, I don't think shimming the needles is going to help. Setting the idle mixture screws to 2.5 turns out usually gets you very close, so it's odd that it won't idle decent. How old is the gas? Air filter good? A couple things you can do before removing the carbs would be to sync them and check for a vacuum leak in the manifolds that connect the carbs to the engine. I might also drain the floatbowls and look at what comes out. If you have condensation in the gas, or it's bad, no amount of adjusting is going to make it run right. Sounds like you might need to remove the carbs and go through them. The idle circuit (Pilot Jets and passages for the idle mixture screws) may be partially blocked. Cleaning the carb and jets properly isn't easy (read-up on it before you take things apart - http://faq.ninja250.org/wiki/Intake) , but you'll never get it to run right unless everything is spotless and properly adjusted.