250 bandit carb issues

[Mad_Sunday]

Hi, I am trying to sort what I believe are carb issues with my wife's 250. I have stripped the carbs and cleared the jets/airways following tips found via this site. The bike has had a problem since we got it. It starts first time (well it does now I freed the choke cable off) and runs fine until it get hot. Once above 4000 rpm it's smooth and runs up to 16,000+ rpm sweetly. Below 4000 it is best described as "iffy". Sometimes it's fine, sometimes it misses on 1 cylinder, sometimes 2 and sometimes just dies. I'm beginning to suspect a problem with the fuel cock because when balancing the carbs with the tank feeding fuel from the bench and in the prime position, it appears to run fine (I only thought about this after putting it in the garage tonight) and I'm thinking the vacuum diaphragm might be leaking? I'm going to try riding the bike on the prime position tomorrow. I've found data on the "sunnyside" website and all the jets seem to be the correct ones. One thing that bothers me is the needle clip position. The data states that the needle is a 5CF9-3. The needle is a 5CF9 but what does the -3 refer too? I thought that it might be the clip ring position, if so is it 3 up from the bottom or 3 down from the top (of the 5 possible grooves). The clip is actually 2 up from the bottom!

Anyone into 250's? Or know about carbs?

Regards, Pete

p.s. picture in the "introduce" section.

[Chris H]

Hi Pete,
The last number is reference to the clip groove as you say and the number is from the top, so number one would be the weakest. 3 will be as your carbs, so two from bott.
Chris.

[pmackie]

and runs fine until it get hot. Once above 4000 rpm it's smooth and runs up to 16,000+ rpm sweetly. Below 4000 it is best described as "iffy"

So...if I understand correctly, the bike runs fine when cold at all revs, then runs poorly at low revs once hot? If so, this would indicate that the air mixture screws/pilot jet circuit are likely too rich. Try adjusting the air screws 1/4 turn at a time and see if it makes a difference. I am unsure if the air screws on the carbs on the 250 control the air or the fuel, so I don't know which way to turn them. Maybe even try 1/2 turn at a time as see what the difference is, then adjust by 1/8s or 1/4s as you dial it in.

The needle jet and needle could have impact, but they basically handle the fueling from 1/4 throttle to 3/4 throttle opening.

[Red01]

Dumb question... how's the air filter? 
A dirty one will make it run rich.

Just trying to attck problems at their simplest level.