can you guys get me close on my jetting?

[badbandit69]

I just bought a 1999 400ex and it had been sitting for about 4 years. The guy i bought it off of bought it just to sell it and he said he cleaned the carb and what not. Its got the popping and snapping on the decel and whenever you let off the throttle all the way. The bike has a k&n and no airbox lid and a white bros. slipon. I messed a lil with the pilot mix screw and it didn't seem to change at all. also the bike doesn't like to idle when cold at all. and it seems to high idle when its warm. So i think im just gonna take the carb off and clean it all really good make sure the jets are clear and what not. But while i have it off i want to make sure the jetting is close. can you guys give me a close guesstimate on what i should be at at about 660ft above sea level?

[drew416ex]

The pilot should be a 40-42, and the main should probably be between a 150-160.

[badbandit69]

thanks for the help. btw what are the stock jet sizes?

[brusif]

148 main, 38 pilot and needle 3rd clip is stock...

[chayes627]

im at about the same height as you and same mods except i keep my airbox lid on and im at 152 main and 40 pilot

[badbandit69]

thanks for all the help guys! btw what part number sparkplugs do the 400's take? also i was told you have to take the gas tank off to get the sparkplug out is this true?

[Speedy 400ex]

Originally posted by badbandit69
thanks for all the help guys! btw what part number sparkplugs do the 400's take? also i was told you have to take the gas tank off to get the sparkplug out is this true?

I the part number i have is for the is plug NKG 4730dpr8z. I thinks thats it.

As for getting the plug out, You dont need to take the gas tank off. But you do need just the right size socket, and one of those bending ratichet attichments that alow you to angle the ratichet.

Thats how i did it.