03 honda 400ex help

[jmaxw21]

Originally Posted by Koopa

I had a 160 with lid off and went up to a 170 dyno jet which is like a 190 kehien. May adjust the fuel screw and see how i acts. It does affect idle a bit.

so just checkin i should get a 138 dyno jet or 150 kehien and adjust the mixture screw thats all?

[Koopa]

Originally Posted by jmaxw21

so just checkin i should get a 138 dyno jet or 150 kehien and adjust the mixture screw thats all?

No worries man. Don't sweat it. I'm happy to help. Changing the jets in the EX shouldn't be any different than the 250R. Don't worry about getting a dynojet. Just go for the Kehien. They are only a couple of bucks each. Yes, were talking feet above sea level. If your between 3000 and 5000 get a 150 or 152. If your below 3000 I'd still find a 158-160. When

I had my lid off my EX I was spot on with a DJ 170 (recommend by DynoJet) which is like a 190 Keihien. I'm at sea level and if you are a keihein 160 sounds right. And adjust mixture screw.

Also, remember. It don't hurt to be running a little rich, you won't notice a bog. But, running a little lean can cause damage.

[jmaxw21]

ok cool ill try a 150 or 152. should i turn the screw all the way in then out 3 turns ? or what i just wana do this in one try thats all

[Koopa]

haha, no man you need a 160. Stock is 148 a 152 will barley be a jump at all. Put in a 160 and yes screw all in and 3 turns out. Do both of these things.

[jmaxw21]

160 ohh lol ok umm what if it still bogs? then what cuz idk how high i am from sea lv

[Koopa]

Make sure engine is warm. It will bog if it's cold.
Are we talking about a bog where it chokes down and the rpm's stay low or are you talking it cuts out all together for a sec when you stab the throttle?

[jmaxw21]

the 2ed one when i stab it. it just falls on its face

[Koopa]

That can be a little trickier to track down. First things first, I'd get those jetting changes done adjust the fuel screw then try it out. I think you'll be surprised at the power gain you'll get from the jetting changes.

[jmaxw21]

do i need a spechil screw thingy for the fule/air screw cuz it looks pritty odd ? and im goin to get the jet today

[Koopa]

I don't think so. Believe it's just flat head screwdriver until '05.