400ex hmf slipon ers

[ny300exrider]

what main jet do you guys run with an hmf slip and and an airfilter. im going to put a 42 pilot but i got a 175, 180 and 185 main with the pipe so do you think one of these will work or do i have to buy others. thanks, i know this topic is discussed too much but i know everyones pipe/jetting specs are different..thanks guys

btw im almost positve hmf recomends a 175 but ill take your advice too

[speedy400]

well, check out my sig for mods but I'm running-
Dynojet 175MJ(from DS650 kit)
DJ needle at 3rd position with clip under the E clip.
45 pilot
fuel screw 3 1/2
-darren

[ny300exrider]

crap, you run a 175 with all those mods and i was thinking my stock 400ex with the hmf slip on would be good with a 175...hmm thanks for the info though, anyone else

[Doibugu2]

I'm running a 142 DJ with no other motor mods. Airbox lid on.

I think you don't even have to change the main jet if you still have the air box lid on.

im runin what it says but i didnt move the clip all the way down and im runnin a 165 normal jet no dynojets. And its still rich.

[livealatimmy]

When i had a HMF slip on i was runing a 148 main DJ with the air fuel screw 2-1/2 turns out and air box lid off. I tried a 155 main but it was too rich on the bottom and seemed like it leaned out on the top end .

[ny300exrider]

well when i get the pipe im going to put it on but leave everything there like the airbox lid and stock jets. if it runs good ill leave it for alittle bit until i go get some smaller jets and do some airbox mods because i was recomended 175 180 and 185 mains so i ordered them but it looks like there will be no need to use them . if it doesnt run good, even with the lid and everything still on im just going to drill holes in the lid then jet it to those mods

[PHIL_B54]

are those the jets they recomend? my jetting is in my sig. and i dont think im that far off. good luck

[ny300exrider]

well on the site it recomends the 175mj 3.5 turns on the air/fuel mixture screw and raise the needle to first clip but for some reason it seems like everyones is alittle lower. im gonna see what it does with stock jets and airbox lid on and if it runs like crap ill drill some holes in the lid, get some smaller main jets to mess with, and just try to do it right.


btw i got my pipe tonight in the mail and boy its perty. im going to wait to put it on until after christmas though.

[MNTNMAN]

I settled on a 150 MJ, 3 turns out on the screw, stock air box w/ K&N. It's a little rich on the bottom end, but good on top. Thats at 2000 feet. At the coast I go to a 160 MJ.

[2001400ex]

I'm using a 155 main jet - I'm in NJ. 3-1/2 turns out. Stock pilot jet; I need a 42 pilot jet now because mine won't start.

[ny300exrider]

Originally posted by 2001400ex
I'm using a 155 main jet - I'm in NJ. 3-1/2 turns out. Stock pilot jet; I need a 42 pilot jet now because mine won't start. im on long island so my jetting is problably going to be closest to yours. thanks for the imput. all your guys replys are so helpful thanks again

[2001400ex]

No problem man.

[cals400ex]

first off, we need to mention that dynojets are not the same as keihin jets. so a 155 keihin is NOT a 155 dynojet. i assume you ordered keihin jets. depending on temperature and altitude, i bet a 152 keihin jet should be pretty close to what you need given that all you have is the pipe. DON"T buy smaller keihin jets. you will be really lean. these people running smaller numbered jets are using dynojets. these smaller numbered jets, like a 146 dynojet are actually larger than a stock 148 keihin jet. as the temp gets colder, you will use larger jets. so, in really cold weather you might want a 155. in really really hot weather you might want a 150. in the months in between, you might use a 152. if you don't want to go through the trouble, you probally can't go wrong with just the 152 or 155. just remember, bigger doesn't mean better when it comes to jetting. hmf's specs are just a little rich. jetting rich with the 175 will make the bike run a little cooler, but it won't have as much performance either. i actually run a 155 in the hot months and a 160 in the really cold months for my 11 compression 406, stage 2 cam, full pipe, etc. good luck

[ny300exrider]

thanks so much that was really helpful. the only reason i need some smaller jets is becasue i only have 175 180 and 185 which dont look very helpful. ill get like 150 to 165 mains and see how they work if the 175 is too rich or if it doesnt run with the stock jets and lid on. thanks again for all the help

btw i do know that the dj are different then the keihn but thanks for explaining that

[PHIL_B54]

good point cal's...mine are keihn jets(i think)

[cals400ex]

Originally posted by ny300exrider
thanks so much that was really helpful. the only reason i need some smaller jets is becasue i only have 175 180 and 185 which dont look very helpful. ill get like 150 to 165 mains and see how they work if the 175 is too rich or if it doesnt run with the stock jets and lid on. thanks again for all the help

btw i do know that the dj are different then the keihn but thanks for explaining that

your bike will probally run fine with both the 148 and 175 in. you will just be lean with the smaller one and rich with the 175. you will probally notice that with the 175 in, the bike doesn't want to pull really hard up top. 2 or 3 sizes too big is enough for me too tell a difference. it won't want to pull up top like it should. buying all of the jets isn't a bad idea. i actually have every keihin jet from 150 to 165. it is helpful if you jet your bike several times a year like myself. good luck

[sickyellow400ex]

did u get a mainjet with your hmf cuz i didnt

i didnt get one either.

[sickyellow400ex]

cuz it sed in that little booklet thing it comes with that its suppose to come with one and mine didnt

[cals400ex]

Originally posted by sickyellow400ex
cuz it sed in that little booklet thing it comes with that its suppose to come with one and mine didnt

i would be calling them up and telling them you want one. :D

[Out_Sider]

with my 330 im running a 155 main and 45 pilot. Everything seems to be aight..but the headpipe turns cherry red if it idles for too long :huh

[2001400ex]

I'm preety sure that means you're running too lean.

[BSTURDIVANT]

The HMF works good with 160 main, stock pilot 3 turns out on air screw, stock clip location.
Should never need more than 165 main with a stock carb.

Also something we learned the hard way leave choke in- it sraightens the airflow and increases bottom end throttle response!

[sickyellow400ex]

would it matter if i got it from a store instead of direct from hmf?

[cals400ex]

Originally posted by sickyellow400ex
would it matter if i got it from a store instead of direct from hmf?

oh no, you can get it from a store. however, if you contact hmf they will send one for free if they were suppose to in the first place. ;)

[cals400ex]

Originally posted by Out_Sider
with my 330 im running a 155 main and 45 pilot. Everything seems to be aight..but the headpipe turns cherry red if it idles for too long :huh


if it turns a little red at JUST idle, i would turn your fuel skrew out a little bit. if it does it at 1/8 to 3/4 throttle, i would raise your needle one position. :)

[400exrapes]

For just an hmf slip n this is what im doing in a few days either 152 main jet or 155 and 42 pilot or slow jet and the 152 will be a little lean and the 155 will be a little rich either way you'll be good im gonna go with the 152 and ill let you all know whats all happenin

[xtullyx16]

hey man this thread is over 4 yrs old! lol :blah:

[400exrapes]

WAHHHHHHHHHH no comment.