Hmf pipe for 2007 400ex?

[That400exGuy]

uhh yeah im wondering if i should buy a HMF sport slip-on for my 400ex??? also, do i need to have the quad jetted or can i just change the fuel to air ratio or watever?? uhh please help!!

[hungus07trx400]

The screw to control the air/fuel ration is just for minor adjustments. Your going to be flowing a lot more air so jetting will be required

[That400exGuy]

k wat kind of jet would you reccomend? dynojet?

[hungus07trx400]

I'm in the process of doing all that now, I ordered a LOT of aftermarket stuff recently and it all kinda came at once. I ordered the Keihin jets because the 400 uses them stock, so it should be a good benchmark as far as knowing how many sizes Ive gone, or need to go, up or down. Same with the Pilots. It depends on elevation, temperature, all that stuff. At a 1000 feet in New Hampshire, where I'll be riding, Im gonna try a 155-160 main jet (keihin) and a 40 or 42 pilot (also Keihin). Then when I get really closes, fiddle with the needle and screw

[Ace Sixx]

Originally posted by hungus07trx400
I'm in the process of doing all that now, I ordered a LOT of aftermarket stuff recently and it all kinda came at once. I ordered the Keihin jets because the 400 uses them stock, so it should be a good benchmark as far as knowing how many sizes Ive gone, or need to go, up or down. Same with the Pilots. It depends on elevation, temperature, all that stuff. At a 1000 feet in New Hampshire, where I'll be riding, Im gonna try a 155-160 main jet (keihin) and a 40 or 42 pilot (also Keihin). Then when I get really closes, fiddle with the needle and screw

Good advice. Stick with the Keihin jets. www.jetsrus.com is your friend.

jetsrus is nice except for everything is individual. So what if you change something or the jet you get inst just right, then you have to order another to try it. I stick with DynoJet

[That400exGuy]

well i was gonna buy the slip-on from the site [ hmfengineering.com] and wen u click add to cart it shows recommended products and they make jets.... soo you think i should but one of em?? its like 60 dollars i think?? that might be easier?

[Eviltanker]

The jets from HMF are close but you will probably need a bigger main. I am running a 42 pilot and a 158 main. I'm near reading Pa,
Where the heck is monongahela?

[That400exGuy]

Originally posted by Eviltanker
The jets from HMF are close but you will probably need a bigger main. I am running a 42 pilot and a 158 main. I'm near reading Pa,
Where the heck is monongahela?

south of pittsburgh just a little on the monongahela river go to google and look at a map