PDA

View Full Version : air screw settings / jets ??????


Banshee_370
09-07-2008, 08:11 PM
ok guys, my 400ex ran ok but i spoke to colby at c&d racing and he suggested to lean out the main a little (iwas running a 155 dynojet) and richen the pilot (i was a stock 38).

installed everything, needle on 3rd clip from top (dynojet needle) and i cant seem to get it to run good at anything below 1/3 throttle. wot seems good but when i stay at constant throttle in the lower rpms it likes to bog and pop and almost die.

i have tried all air screws combos from 1 and 1/2 all the way to 3 and 1/2 out and still cant get it. i noticed it after about 45 minutes of riding when we got to a certain part of the trail we decided to just coast on instead of riding hard. when i got back home i also noticed that one of the screws to hold the float bowl is missing...perhaps there is an air leak? i sprayed it with carb cleaner while the bike was idling and head no rpm gain so i dont think it is the problem.

can anyone please help? my mods are a white bros slip on, k&n filter with outer wear, lid on and choke plate removed.

thanks
drew416ex
09-07-2008, 08:20 PM
what size pilot? Did you change it out when you changed the main?
Banshee_370
09-07-2008, 08:32 PM
im sorry i thought i put that in there....its a 42 pilot
drew416ex
09-07-2008, 08:40 PM
im not sure. I would have said put the 42 pilot in also. Go back to the 38 and see what changes and we can go from there. Maybe where you ride a 38 is just fine.
Banshee_370
09-07-2008, 09:16 PM
i had alot of poppingon decel with the 38 and it woulnd idle so great until it was 100 percent warm...choke or not....

i also took the lid off to get some more air in there and see if i was rich and it still made no difference.....is it bad to run only 3/4 or 1 turn out on the mixture screw?
drew416ex
09-08-2008, 03:44 PM
I dunno. Maybe try a 40. It doesnt make sense.
01440ex
09-08-2008, 06:40 PM
popping on decel is because of your mixture screw....it should be around 3.5 to 4 turn out....jets have nothing to do with the popping on decel
drew416ex
09-08-2008, 08:22 PM
Originally posted by 01440ex
popping on decel is because of your mixture screw....it should be around 3.5 to 4 turn out....jets have nothing to do with the popping on decel

The pilot jet does. The mixture screw fine tunes the pilot. If you are 3.5 - 4 turns out, your pilot is too lean.
Banshee_370
09-08-2008, 09:54 PM
ive read about the idle drop method to tune your pilot and air screw. i just order a tach so i will hook it up and see if that helps.