yes, another jetting question
 

My friends GP 300 is on stock carb setting, except that the main jet is a 170 instead of the standard 175. I checked the float height and reduced it a bit as it was set too high and the carb spilled gas as soon as you leaned it over 20? degrees.

So the current set up is:

N1EF needle in the third groove, main jet 170, pilot jet 42, AS 2 turns out.
Altitude: 660 to 1200 feet
Temperature: 88 F
Premix: 60:1 Silkolene Fuchs Titanium Oil

Surprisingly the bike runs very well with the N1EF only burbles a bit down low. Its mostly ridden on the pilot jet, normally does not get high revs. Its overly rich and always has much spooge on the exhaust.

I have a NECW needle on the shelf and would like to try it. I do believe it would work very well with the current jets but I don't want to ruin his bike. If it was mine I would not hesitate a second and try it.

Can anyone tell me the differences between the two needles. I know the NECW is leaner than the N1EF but I don't know much about the N1EF. I expect the bike to run leaner everywhere without the danger of seizing.

I can't ride behind my buddy because his GG smells like its spraying pure gas out of the exhaust. I had a headache last time I followed him...

When I changed to the NECW alone, it felt a lot cleaner though most of the range. Nothing to substantial but I could definitely tell by the seat of the pants.

My bike also runs best at around 2 turns out on the mixture screw but I am running 1 1/2 till I get it sorted.....I don't want to lean the sucker.

My bike is still running fat and burbling up top, sometime this week I'm changing from a 172/42 down to 170/40 to see what happens.

If your 2 turns out on the pilot, maybe drop it down to a 40 and try to get the mixture screw to around 1 turn.

All that said, my bike is an ec not a gp.

NECW has a longer and thicker straight section. Much leaner off idle.. That is where most of the difference is.. 0-1/4 throttle range. Find the clip position that gives best feel from 1/4 upwards... Main will be comparable.

Many thanks rodent! Are you on the NECW right now? I will try the NECW in his bike with the 170 and 42 jets then see how its running, if necessary reduce the pilot to a 40.

I see, that's probably why people recommend it when they have the well known "low down burble".

Many thanks Jakobi !