Got my HMF Slip-on

[LazeR]

Well it finally came today! I think the jetting is pretty close.... i did a 42 pilot, 2 turns out on the fuel screw. and a 165 DJ main. Its backfiring a tiny but on decel when it revs down. So i know its not the main, i think its the needle... Would raising my needle (lowering the e-clip) most likely solve my problem ? Also i'm running with my air lid off and i have a K&N filter

[jcs327]

I am running a 155 main, 42 pilot, left the needle clip and air screw alone for west tn area and it runs awesome with K&N with outerwaers and no lid with my hmf slip on. HMF rocks. it will really wake the 400 up.

[LazeR]

What is your elevation ? Im at like 400 feet! My bike seems to run really good...Very suprised with the power gains! I love HMF!

[nosliw]

ive got a slip on with a kn filter, no airbox lid, and im running a 152 mj, 42pj, 2 1/2 turns out on fuel screw

[cals400ex]

turn the fuel screw out another 1/2 turn or so and see if that fixes your backfiring problem.

[LazeR]

Originally posted by cals400ex
turn the fuel screw out another 1/2 turn or so and see if that fixes your backfiring problem.

I think im going to try that tomorrow after work. thanx

i'll let you know how it turns out

[TRXRacer1]

That 165 main is robbing a little power from you(rich). Drop it to a 155.

[LazeR]

Originally posted by TRXRacer1
That 165 main is robbing a little power from you(rich). Drop it to a 155.

I'm gonna wait till i can do some 4th and 5th gear runs with it....right now i can't get outa 3rd gear. it pulls second strong all the way to the rev limiter though and top end of 3rd is strong as well.... I'll see, prolly won't really be able to do anything until tomorrow since i have to work today!

Thanx for the tip though,

[meanyellow03ex]

I too just installed a HMF slip-on, filter, modded airbox lid. I didn't want to guess at jetting so I had mine dyno tuned. With a 155 main jet, it was too lean between 16:1 and 18:1 at higher rpms. It took a 170 keihin jet to correct the air/fuel ratio to around 13:1 - 14:1 at high rpms. Most tell me I'm too rich but the numbers show it's right and both dyno graphs were pretty close so by judging by seat of the pants, it would be impossible to tell what is going on, even if you were running a tad lean. Your 165 dynojet shoulf be close to my 170 keihin jet. You should be close.. maybe back out the screw a half turn..

[LazeR]

Originally posted by meanyellow03ex
Your 165 dynojet shoulf be close to my 170 keihin jet. You should be close.. maybe back out the screw a half turn..

The fuel screw and main jet don't have anything to do with each other :confused:

[LazeR]

Originally posted by cals400ex
turn the fuel screw out another 1/2 turn or so and see if that fixes your backfiring problem.

it was raining so i haven't had a chance to test it out yet... but what do you think about my main jet cals ? You seem to be really good at starting ppl off with jetting... Does a dj 165 sound a lil rich ? Hopefully Sunday the weather will be better

[TRXRacer1]

I've got a T-4 slip on with dyno jet/K&N kit and I've got a 148 main and it runs great. I tried the 155 and lost a little.

[LazeR]

Originally posted by TRXRacer1
I've got a T-4 slip on with dyno jet/K&N kit and I've got a 148 main and it runs great. I tried the 155 and lost a little.

How many turns out on your fuel screw ? and what pilot jet ?

[cals400ex]

Originally posted by LazeR
it was raining so i haven't had a chance to test it out yet... but what do you think about my main jet cals ? You seem to be really good at starting ppl off with jetting... Does a dj 165 sound a lil rich ? Hopefully Sunday the weather will be better

you can do what you want. i go by plug readings on my bike. i do also take feel into consideration. i like the smaller ones because you will get more top speed. the larger ones will usually slow you down a bit but may make the bike run cooler. i have read dyno's that showed a piped 400ex needing around 165-170 and i have seen other dynos showing a built 416 needing around a 152-155. it is just hard to tell. the dynos tend to vary quite a bit from what i see. ewalker, a member on this site, has messed with dynojets quite in depth and he feels a dynojet 150 was about perfect for a piped 400ex. however, elevation and temperature matter too. if it was me, i would start with the 155 dynojet and go from there. good luck

[LazeR]

Well i turned the fuel screw out another ½ turn and dropped the main from a 165 to a 160, and it made a world of difference. I took out my plug and it was a light-medium brown color. and it runs awesome! Also turning the fuel screw out another half turn took away the little popping it had.



Thanx for everyones help

[TRXRacer1]

Originally posted by LazeR
How many turns out on your fuel screw ? and what pilot jet ?
Stock pilot jet and 2 1/2 turns out.

[JDiablo]

sweet....when did you order it?do you have the quiet core?

[LazeR]

Originally posted by 300exrida
sweet....when did you order it?do you have the quiet core?

I ordered it about 2 weeks ago, and recieved it thursday. I do have the quiet core, it quiets it down tremendously! Within minimal power loss! I'm very impressed with my HMF!

[JDiablo]

thats sweet....how much louder then stock would you say it is?

[LazeR]

Originally posted by 300exrida
thats sweet....how much louder then stock would you say it is?

a lot, its prolly at like 103db or so

thats without the quiet core....quiet core is suposed to bring to around 94-96 db which im sure it does

[JDiablo]

man so i bet a full system is a lil louder then,o well...i think a stock without that stupid spark arrestor thing is like what 92?93db's?

[LazeR]

I don't know.... i left my stock pipe alone. I doubt the full system is much louder, it sounds good. Its loud but it doesn't hurt my ears or anything. With the quiet core, it doesn't really sound that much louder than a stock pipe, but its definately louder! On the dunes here the db limit is 93... so im hopin with the quiet core it doesnt sound loud enough to check me

[TRXRacer1]

A full system shouldn't be louder.

[LazeR]

Originally posted by TRXRacer1
A full system shouldn't be louder.

I wasn't sure, i didnt really think it would be. But there is always the possibility :confused:

[JDiablo]

idk i thought you have a bigger headpipe,i didnt mean like 5 db's louder i meant a lil louder like 1db if even

[TRXRacer1]

Same motor, same silencer and you won't flow much more with an oversized pipe.

[hondarider2006]

Originally posted by LazeR
I don't know.... i left my stock pipe alone. I doubt the full system is much louder, it sounds good. Its loud but it doesn't hurt my ears or anything. With the quiet core, it doesn't really sound that much louder than a stock pipe, but its definately louder! On the dunes here the db limit is 93... so im hopin with the quiet core it doesnt sound loud enough to check me

93 db....man I hope you have your stock pipe when I come down. Running that TC shorty I am well over 105...:devil:

[Abrab916Ex]

yo.....HMF sounds great, but do the they have a full system for the 400ex (ceramic coated)?...........or a silencer with a ceramic coated header?and...what site should i get it off..........thanks........prolly ganna get this pipe, sounds hot!

[hondarider2006]

Originally posted by Abrab916Ex
yo.....HMF sounds great, but do the they have a full system for the 400ex (ceramic coated)?...........or a silencer with a ceramic coated header?and...what site should i get it off..........thanks........prolly ganna get this pipe, sounds hot!

Yes they offer a full system for the 400ex. I'm not sure if its ss or ceramic coated, but I do know they will powder coat the silencer. They will also shorten the silencer for you if you want it for mx;)

[muddy400EX]

hey LazeR, wered you order your HMF from and how long did it take. im just wonderin cuz im wantin to get an HMF for mine and im wonderin whats the best place to buy from. and do you have any pics:)

[LazeR]

Originally posted by muddy400EX
hey LazeR, wered you order your HMF from and how long did it take. im just wonderin cuz im wantin to get an HMF for mine and im wonderin whats the best place to buy from. and do you have any pics:)

I ordered it from C&D racing (site sponsor) and they order from HMF, it took a little less than 2 weeks, and i was told it will take a week or 2 because HMF is really busy this time of year i guess. Great service from C&D, when its time for new parts i will order from C&D. No pics right now. Its all dusty, i have a black powdercoated silencer.