Need 416ex jetting help ASAP

[FastHonda400ex]

I've got a JE 10.8 to 1 piston, a Stage 2 Hotcams cam, a Big Gun Race Series pipe with a quiet core, and essentually no airbox lid. It has Dyno Jet Stage 2 jetting kit in the carb with a 165 main, and a 40 pilot jet. Right now the temp outside is 28* and I noticed my headpipe glowing just a little while warming it up. I'm assuming I'm running a little lean and need to put in the DJ170 main, or do I just need to richen the air mix screw a little more? It does pop a little bit on deceleration too. Big Gun recommends a DJ170 main and 40 pilot under 3000 feet elevation. Please reply ASAP so I can get it dialed in tonight.

Thanks very much,
Doug:D

[pnut420]

If you are running lean while idling then you need to up the pilot jet, you may need to go bigger on the main jet also, I would up the pilot jet and main jet and maybe even the clip.

[WhiteBros400ex]

i agree with pnut420 i just got my 400 back and its a 416 not with a 11 to 1 compression and stage 2 hot cam and i run a 165 and idk what polit lol i 4 get but go with what he said

[speedy400]

well, my mods are below, my jetting is-
175 dynojet(from ds650 kit)
48pilot
3 turns out
DJ needle 3rd clip from top with washer under it
-darren

[cals400ex]

Originally posted by FastHonda400ex
I've got a JE 10.8 to 1 piston, a Stage 2 Hotcams cam, a Big Gun Race Series pipe with a quiet core, and essentually no airbox lid. It has Dyno Jet Stage 2 jetting kit in the carb with a 165 main, and a 40 pilot jet. Right now the temp outside is 28* and I noticed my headpipe glowing just a little while warming it up. I'm assuming I'm running a little lean and need to put in the DJ170 main, or do I just need to richen the air mix screw a little more? It does pop a little bit on deceleration too. Big Gun recommends a DJ170 main and 40 pilot under 3000 feet elevation. Please reply ASAP so I can get it dialed in tonight.

Thanks very much,
Doug:D

try turning your fuel skrew out some before buying a new pilot jet. this should fix your glowing header problem at idle.

[FastHonda400ex]

Thanks for the replies:)

I decided to install the DJ170 main jet in the carb, and I adjusted the air/mix screw out to 3 1/2 turns. It runs great now for the colder temps outside(snow:D ), and it didn't pop on deceleration anymore. There's a faint glow from the header pipe for a little bit, but I think it's because of the hot air going through the header pipe when the pipe is cold. After it was fully warmed up, it didn't glow anymore and I ran it wide open down the road out of town to test it. I think I'll buy a 42 pilot jet tomorrow just in case I need to richen the idle circuit some more, because of the 3 1/2 turns out on the mixture screw. I don't remember what the max turns out from seated on the mixture screw is?:huh

Thanks for the help,
Doug

[cals400ex]

Originally posted by FastHonda400ex
Thanks for the replies:)

I decided to install the DJ170 main jet in the carb, and I adjusted the air/mix screw out to 3 1/2 turns. It runs great now for the colder temps outside(snow:D ), and it didn't pop on deceleration anymore. There's a faint glow from the header pipe for a little bit, but I think it's because of the hot air going through the header pipe when the pipe is cold. After it was fully warmed up, it didn't glow anymore and I ran it wide open down the road out of town to test it. I think I'll buy a 42 pilot jet tomorrow just in case I need to richen the idle circuit some more, because of the 3 1/2 turns out on the mixture screw. I don't remember what the max turns out from seated on the mixture screw is?:huh

Thanks for the help,
Doug


actually, i don't think you are suppose to go out a full 3.5 turns. however, if you do it will work just fine. were your headers glowing when you were at complete idle or did they glow when you were hitting the gas with 1/8 throttle or more? also, i think your too big on the main.

[cals400ex]

Originally posted by cals400ex
actually, i don't think you are suppose to go out a full 3.5 turns. however, if you do it will work just fine. were your headers glowing when you were at complete idle or did they glow when you were hitting the gas with 1/8 throttle or more? also, i think your too big on the main.


i would think you should be rich enough with your pilot/fuel skrew. with a 42 in my built motor, i have it set at 2 turns out. also, the backfiring stopped because you richened up your fuel skrew. it was not because of the larger main probally.

[FastHonda400ex]

i would think you should be rich enough with your pilot/fuel skrew. with a 42 in my built motor, i have it set at 2 turns out. also, the backfiring stopped because you richened up your fuel skrew. it was not because of the larger main probally.

Cals400ex,

You're correct on the fuel screw, I richened it up a little bit and the popping went away. I put the 170 main in to see if it acted differently, and I think it's a little too rich myself even though it seemed to run okay. The header pipe faintly glowed at around 1/8 throttle or a little more when I was just lightly revving the motor and then letting it idle again(doing this several times). I think I had the fuel mix screw set at 2 3/4 -3 turns out with the 40 pilot before I adjusted it out to 3.5 turns out, and it was popping on deceleration a little bit before the adjustment. I'll pick up a 42 pilot tomorrow if you think I should bump up the pilot jet? Let me know.

Thanks,
Doug

[cals400ex]

i wouldn't buy a larger pilot yet. i would get the bike up to full temperature and ride it around a bit. then, let the bike sit and idle for 2 or 3 minutes. don't give it any gas, just let it idle. then shut it off and check the plug. see what color it looks. if it is white, you should get a larger pilot. if it is tan or gray, you should be pretty close. if it is black, your too rich.

if it is glowing at 1/8 throttle or so, your too lean on your needle. if you run a dynojet needle, i think you can make adjustments by 1/2 the notches in the needle by using the washer in the kit. for example, if you have the needle in the 3rd clip position, you could leave the needle in that position and put the washer under the needle. if you already have the washer under the needle, you could put the clip i the 4th position and take the washer out. if that still too lean, you could leave the clip in the 4th position and put the washer under the needle. etc