1 pilot jetsize equils how many pilot screw turns

[mattlloyd50]

hi im riding a 2005 ec250 in the u.k about 300m to 500m above sea level with 50-1 fuel mix and it was running rich on the pilot circuit, bogging on idle to 1/4 throttle and lots of spooge.
i found the best response was with the pilot screw 3 1/2 turns out with a #40 jet.
i fitted a #38 pilot jet but i still need the screw about 2 1/2 to 3 turns out for crisp running.

i was expecting the jet change to make more of a difference than about 1/2 a turn of the pilot screw.

is this normal? if so im going to try another size leaner.

thanks for any advice and help
matt

 

[Jakobi]

If you are using the stock needle (N1EF) it has a really short straight section and a really rich first taper. Also if the idle screw is turned in a lot (lifting the slide quite high) then you could be all but bypassing the pilot circuit and find that having the AS out so far is just working to lean off the first taper of the needle a bit. If this is the case you'll find the air screw has a very limited effect. The general consensus is that the stock needles are crap.

Check the jetting DB to compare against others with similar conditions and vintage bikes. The later ones use different carbs requiring different setups.

 

[mattlloyd50]

ok thanks il check the jetting db and look into the needle