HMF PIPE & jet kit

[joe0899]

I have a 02 400ex. I have been looking into a pipe and I think I am going to go with a HMF slip-on. They also sell a jet kit pretty cheap. The web-site says to go with a 175 main jet and move the clip up one slot. I need to know if this works because 175 sounds a little big.

[YZROOSTINYA]

look at my sig

I run a 155

:rolleyes:

[Castor-426ex]

dont listen to hmf they have no clue

i just slapped a full system on my 426 and they reccomended a 200 main

im running a 165
with the needle in the middle
and a 42 pilot

[knighttime]

Originally posted by Castor-426ex
dont listen to hmf they have no clue

i just slapped a full system on my 426 and they reccomended a 200 main

im running a 165
with the needle in the middle
and a 42 pilot

i thought yours popped on decel?:confused: :eek2:

[Pappy]

i run a 160 and its still a bit rich with the air lid on....ill tinker with the airscrew and it should be fine:)

[Castor-426ex]

Originally posted by knighttime
i thought yours popped on decel?:confused: :eek2:

it does...

screw it

it runs awesome besides that

Originally posted by Castor-426ex
it does...

screw it

it runs awesome besides that


MIght be chitty gas too castor....:ermm: never really thought of that. I know you've had a nightmare dealin with the full HMF exhuast.. :mad:

[joe0899]

I live in southwest ohio and the only other mod I will do is an UNI-Filter. Other than that I need to Know what jet(s) to get. I would like to hear from someone with the same set up and see what they recomend. I really only want to have to re-jet once and not keep tearing into the carb.

[Pappy]

joe....if all your doing is a uni and still running the airbox lid you shouldnt have to rejet.

[Doibugu2]

I have the HMF slip on K&N with the air box lid on. I have the 148 DJ in mine with the needle up a notch.

[YZROOSTINYA]

put in a 150 main and have fun

42 pilot if you pull the choke

[hondarider2006]

look at my sig.


I am still at stock jetting and it pops on decel. It also runs pretty hot. I looked at my plug last night and could tell I was running lean. Should a 150 help this? I am gonna leave the choke on for winter time use..

[RIDER11X]

Originally posted by hondarider2006
look at my sig.


I am still at stock jetting and it pops on decel. It also runs pretty hot. I looked at my plug last night and could tell I was running lean. Should a 150 help this? I am gonna leave the choke on for winter time use..

:huh You deff. should try to richen that up before you do anymore damage than you may have already done. :ermm:

[deepcj7]

I have a Pro Design filter, HMF slipon, grinded header welds and I run a 152 and a 40, clip in stock position. It's pretty close to spot on but I have not yet tried a 155. Hope that helps.;)

[400EXIAN]

So i take it the 175 it calls for would be outrageous and overboard?!?!

[hondarider2006]

yeah thats way to rich. I put a 160 in last night and its almost perfect. A little rich but nothing a few holes in the airbox lid can't solve....:cool:

[RIDER11X]

Originally posted by hondarider2006
yeah thats way to rich. I put a 160 in last night and its almost perfect. A little rich but nothing a few holes in the airbox lid can't solve....:cool:

What's your elevation? That is important.

[joe0899]

I finally got my parts from C&D. I put on a HMF slip-on, K&N w/ outerwear, 158 main, and 40 pilot. What a difference! The pipe is loud as *****. The bike runs 10 times better and has a lot more low - end and mid range power. I ran with the air box lid on and off and couldn't tell much of a difference except it is louder. I will drill a few holes in the lid and see what that does. I raced a 03' stock 400EX and smoked him. I have holeshots on the back so I hooked up better than him but on the road I still beat him. I highly recommend these upgrades if you want to wake up your quad. ( By the way thanks for all the replys. This site kicks booty!)

[fmf400ex]

well i should be getting my full hmf system today from them. and they are sending me a 190 and a 195 for my elevation, but i gues i will just have to experiment with the different jets and air/fuel mixture screw. Well was the ai/fuel mixture the same 3.5 turns out?

[joe0899]

I went 3 turns out.

[fmf400ex]

Huh? they told me 3.5 turns out. Well i guess i will have to mess around with it. It is supposed to come in today.:D

i have a hmf slip on with a k&n filter and five 1" holes in my air box lid. I run a stock 170 mj with 3.0 turns out on the sir fuel mixture and i went one clip down from stock position. its in the 4th position. Works GREAT

[hondarider2006]

I got my jet kit in last week. I jetted with a 170 without the lid on. And I put the clip on the 4th position on the needle. Not sure where the mixture screw is, somewhere around 3-3 1/2, but it runs great!

[northeast400]

Mine runs perfect ( look below)

[bagzrancher1]

HMF has no clue what they r talking bout so if u r going to get that i would probably run a 165 unless u have any airbox mods maybe even try a 160 or so.

[RIDER11X]

They seem to go a bit rich on their recomendations, but it's probably to keep people from burning holes in pistons and blaming them.:ermm:

[fmf400ex]

well they gave me a 190 and a 195 for my elevation. so i am going to try these but if they dont work. then i will probaly try a 165 or somethin down that way.

[RIDER11X]

CAUTION: Work down through the sizes so you dont go too lean. Most shops allow you to return the jets you don't need.;)

[fmf400ex]

Ok thanks for that info rider. thats what i was thinkin of doing.

[joe0899]

Last night I rode a little and my quad was acting kinda funny. When I would punch the gas hard it would just bog down or just quit. It runs great if I just ease into the gas. Once the rpm's are up I can punch it and it is fine. I was wondering if it is running to rich or lean and if I can maybe just adjust the air fuel mixture. It also has a little black smoke from the exhaust when it is first started and I rev it up.

[ryanh250ex]

Originally posted by joe0899
Last night I rode a little and my quad was acting kinda funny. When I would punch the gas hard it would just bog down or just quit. It runs great if I just ease into the gas. Once the rpm's are up I can punch it and it is fine. I was wondering if it is running to rich or lean and if I can maybe just adjust the air fuel mixture. It also has a little black smoke from the exhaust when it is first started and I rev it up.

hmmm.... i would lower the e-clip position on the jet needle a notch or two. i was having the exact same problem with my 250ex after i added a T-4 exhaust, and after i dropped the clip position to the 5th groove from the top it ran like a charm (it still does it once in a while, when it's not warmed up or when it's real hot).

try that, and tell us how it works.

[Matt102]

Yes, HMF does tell you something way too rich because if its too lean and you blow your motor you blaim it on them. They do it with all their quads.