Put A HMF S/O on,Now I have No Bottom End Power?

[EnViOuS1]

Hi Im new to the forum and to 4 wheelers as well.Today I put a HMF S/O on my 05 TRX400ex,The only other mod I have is a K&N with outer wears with the lid on,And I live in Florida.Well I put the exhaust on along with the supplied jets from HMF,I didnt adjust the fuel screw due to not knowing how to adjust or even finding a tool that u can use to adjust it,it looks like a half circle and I have no idea what to use to adjust it or how many turns,Now along with that I took the bike out for a spin and now it has NO Botton End Torque barely lifts the fronts ne more,can you help me please!LoL!Thanx in advance for n e help u can provide.:cool:

[6858-400ex]

you must jet the carb :rolleyes: :rolleyes: at my elevation im runnin a main jet 160

when u jet it correctly u will have a lot more bottom end

[EnViOuS1]

Hey thanx for the quick response, but I did Re-Jet the Carb with the jets that HMF gave me,I just didnt adjust the fuel screw.:cool:

[phildogg]

what jets did they send you? just curious because they sent me a 165 and it was way to big. let us know but its probably way to big a jet. whats your elevation?
phil

[EnViOuS1]

Hey I Live in Florida so my elevation is damn near sea level,LoL! Um they sent me a 152.

[Pappy]

it sounds like the air screw may need adjusting. they do make a tool that helps, but a long thin flatblade screwdriver works. back out 1/2 a turn and see if it helps.


if you get it all out of wack, screw it in until it hits the seat (do not tighten it) and then back it out 2 1/2 turns from the seat. you also may need to raise the needle to help bring back some of the bottom end.

[EnViOuS1]

For an 05 A long flathead screwdriver will work? the adjustment look like a half circle like a "D",any idea what to use for that?Ill note how many turns tho ,Also where is the clip located on or in the carb?thanx for the help!

[Pappy]

sorry, i wasnt aware the 05 had changed regarding the carb. the previous year 400ex's were not like that design.


to get to the needle, you will have to remove it from the carb. id be inclined to not tell you how on the 05 becuase i havent seen the carb and wouldnt want to mislead you with bad instructions.

im sure someone with an 05 will jump in and explain it or i will try and get a 05 to look at. its usually not that bad of a task.

[xc_racer1]

im runnin a 160 jet with 2.5 turns for air screw
and i would recomend getting the uni air filter
if u dont have any bottom end then it would def. be the air screw
i wouldnt run it much till u figure it out b/c it will end up seizing the motor and then ur just gonna get into big money

[EnViOuS1]

Seizing the motor?how so?:huh

[trx400exxracer]

I live in Georgia and my main is like 165 or 170 I run no lid Uni air filter and have a hmf slip on
I would recomend runing vents in your air filter lid not a big fan of K&N though
160 main = with air filter vents & quit core
165 o170+ no lid and no quit core

[underpowered]

i would say go to a 165 MJ with 3-3.5 turns on the air fuel screw. this is what i ran in northern KY with an uni, hmf slip on, and air box lid off.

[EnViOuS1]

Hey everyone thanx for all the Input,but does n e one know what I can use to adjust the fuel screw?Like I said above its shapd like a "D" And I cant find N E where a tool that u can use for adjustments.LoL! I know someone has moded their 05's they ve been out for a year now.:cool:

[400exc]

where is the fuel screw on ur 05 400? mine is on the bottom of the carb, on the side that the pipes arent on, it is a thing u can use a flat headed screw driver to turn with

[EnViOuS1]

I belive its in the same spot but in the 05's they changed the adjustment screw,I guess to make it harder to mod?or so u would have to take it to a dealer to get them to do it,I called my local dealer the can do it,they have the tool,But they want $170 to do a jet kit:eek2: It calls for two hrs at $85 an hr, it took me 30 mins to put a HMF S/O on and rejet the carb,but I didnt mess with the screw i didnt know how:D So now im trying to figure out what to use so i can adjust and get back to riding.

[ryann mx68]

i had the same prob with my air screw, its "D" shaped. all i did was take a small flathead screwdriver and carved a slot in the air screw, { its soft brass } only took a minute, then you can adjust as needed.

you cant change the needle clip position on the "05's", because there is only 1 groove on the needle, you'll have to get a needle from a previous year.

when you get it jetted right, youll feel immediate improvement on the low end. that 400 will want to wheelie outta all the corners.

hope this helps..

[400ex28]

get a TC :devil: