still need some 400 ex jetting advice.

[casey_lamm]

Please give some advice if you can.

Ill start by saying I don't want to run my bike lean. I would rather go rich and not worry about damaging the engine.

The bike 07 400 ex. Mods HMF exhaust, K&N stage 1 power kit.


The way the bike is setup.

I upped the pilot to a 140...awesome! STARTS LIKE A DREAM.

I followed the direction for the kit...which setup as a dj146 main jet.

fuel mixture out 3.5 turns from seated.

Again exactly as the directions state from dynojet for my alt.

The bike runs great...

My only concern is that it might be too lean. How can I tell that? Both by pulling the plug...but I want to know what to look for when im on the bike to indicate this. It seems to have great power.

When Im up high in 3rd or 4th gear and let off the gas... I may get a slight grumble or hickup out the pipe...but its not a full backfire at all...i would better describe it as a "burp"...and it doesn't happen on every decel...

My reason for concern is that the engine does get pretty hot... I do not sit and let the bike idle...only for the 5 min warmup...Im running 10w40 honda oil...going to use 20w50 but they were out. Also the slight grumble im talking about. ...I don't know if its enough to worry about.


So give me some advice so I can dial this thing in perfectly...if there is such a thing! :)

Instructions I followed:

"STAGE ONE INSTRUCTIONS
1. Remove top carb plate. Remove the slide lift arm screw and the two
needle plate screws. Flip the linkage forward and remove the slide
(Fig. A).
2. Install Dynojet needle on groove# 3 for applications below 5000 feet,
groove #2 for above 5000 feet, using all stock spacers. Install the Dynojet
washer above the E-clip.
3. Remove stock main jet. Replace with the Dynojet Main Jet Adapter
(DJA001). Screw the Dynojet main jet provided into the Main Jet Adapter.
If you are running the stock exhaust use the DJ142 below 3000 feet,
DJ138 from 3000 to 6000 feet and DJ134 above 6000 feet. If you are
running an aftermarket exhaust, use the DJ146 below 3000 feet, DJ142
from 3000 to 6000 feet and DJ138 above 6000 feet. Be sure that the jet
you are changing is the main jet.
4. Locate the Fuel Mixture Screw (Fig.B). For 2005 models ONLY use the
tool provided (DT008) to adjust the mixture screw. For 1999-2004
models, use a flat blade screwdriver. Turn the mixture screw clockwise
until it seats, then turn out 3.5 turns below 5000 feet or 3 above 5000 feet."

[CarGuy7a]

the things i listen for when riding is when you stab it full throttle (i usually wait till second gear to hit it good) go through a couple gears at full throttle and let it wind out. if it boggs out it's too rich. if it makes a popping sound then it's lean. if it doesn't make either then you have it close. the only real way to tell is do some testing one day when you have plenty of time to change some jets. go one size bigger and see how it runs. go one size smaller and see how it runs.

i know the directions say to turn it out like 3 to 3.5 turns out that is the limit on the fuel screw. usually anything over 3 turns there is no noticable difference. if it seems a little lean on the bottom end (idle to half throttle) you might bump your pilot to a #40. i had to put the 40 when i put the modded air box lid on b/c the 38 was too lean at 3 turns, it wouldn't even start at full choke.

hope that helps

[casey_lamm]

it does. perhaps one reason I don't seem to be having many problems is that i did the #40 from the get go...just because I knew it would be easier to start in the winter.


It doesn't bog out for sure... as for a popping sound...I really don't remember any...but im not sure I know what that sound would be....

Perhaps a video with sound is in order... unfortantely with the newborn, I won't get to ride for 2-3 more weeks. It stinks be 5 hrs away from the bike. Im trying to talk the wife into a truck, so I can bring it up here. right now I only get to ride when I go back to our cabin...


Thanks for the advice...as far as spark plug....i pulled it and it looks pretty good. i would say im darn close...in fact if I can prove its slightly rich right now, I would leave it alone... I have a feeling if anything it might be just a tad lean... though again, im not hearing a popping sound.




Originally posted by CarGuy7a
the things i listen for when riding is when you stab it full throttle (i usually wait till second gear to hit it good) go through a couple gears at full throttle and let it wind out. if it boggs out it's too rich. if it makes a popping sound then it's lean. if it doesn't make either then you have it close. the only real way to tell is do some testing one day when you have plenty of time to change some jets. go one size bigger and see how it runs. go one size smaller and see how it runs.

i know the directions say to turn it out like 3 to 3.5 turns out that is the limit on the fuel screw. usually anything over 3 turns there is no noticable difference. if it seems a little lean on the bottom end (idle to half throttle) you might bump your pilot to a #40. i had to put the 40 when i put the modded air box lid on b/c the 38 was too lean at 3 turns, it wouldn't even start at full choke.

hope that helps

[Sparky_20]

i leave my jetting slightly rich and i have a little pop on decel, its no big deal. Just ride and enjoy the power.

[CarGuy7a]

yeah some popping on engine decel is very normal. if it's really bad it's either an exhaust leak problem which is an easy fix b/c there really is only 2 places for leakage. where the muffler slips on the head pipe and the exhaust gaskets at the head.

mine popped quite a bit until i found the leak at the head pipe and put a clamp on it.

as far as the popping sound under hard accel. you will hear it rev up then start like cutting out. it kind of sounds like when you bang the rev box only alot sooner.

but yeah it sounds like you are pretty much spot on your jetting if it's doing neither. the way i've learned is just through trial and error. it's kind of hard getting it exactly close with a dynojet kit b/c they don't give you the in between jets. they go in like increments of 5's like 150 155 160. i think there are a couple in my kit that are like 146 and 142 or something like that.

[casey_lamm]

im going to take some videos of it with sound this weekend.



Originally posted by CarGuy7a
yeah some popping on engine decel is very normal. if it's really bad it's either an exhaust leak problem which is an easy fix b/c there really is only 2 places for leakage. where the muffler slips on the head pipe and the exhaust gaskets at the head.

mine popped quite a bit until i found the leak at the head pipe and put a clamp on it.

as far as the popping sound under hard accel. you will hear it rev up then start like cutting out. it kind of sounds like when you bang the rev box only alot sooner.

but yeah it sounds like you are pretty much spot on your jetting if it's doing neither. the way i've learned is just through trial and error. it's kind of hard getting it exactly close with a dynojet kit b/c they don't give you the in between jets. they go in like increments of 5's like 150 155 160. i think there are a couple in my kit that are like 146 and 142 or something like that.

[CarGuy7a]

sweet. hey i was playin with the jetting today in mine and i went up from a 160DJ to a 165DJ main and i did notice a little heat difference on my legs. it didn't feel as hot. and it actually ran pretty close to the same as the 160 but you could tell it was a hair richer. but i'm also running a vented airbox lid so that's why i run that big of a jet.

you might try goin up one size. it wouldn't hurt to try it.

[casey_lamm]

Thats the plan...the main jet isnt that hard to get too...

I think ill but in the next one up and see what happens..


Originally posted by CarGuy7a
sweet. hey i was playin with the jetting today in mine and i went up from a 160DJ to a 165DJ main and i did notice a little heat difference on my legs. it didn't feel as hot. and it actually ran pretty close to the same as the 160 but you could tell it was a hair richer. but i'm also running a vented airbox lid so that's why i run that big of a jet.

you might try goin up one size. it wouldn't hurt to try it.