Is this too lean

[Homerx]

I know there are a thousand jetting threads but I have no place to get my quad wound out for a plug chop, and I don't want to hurt the engine. What I have is 01 stock bore,lid on,uni filter,Lexx mxe Slipon,400ft and 0 degrees F. Running 42 Pilot and 155 main kehin jets. Thanks to all.

[sprayedgt]

If it's not perfect I'd say it's a little on the rich side. I would put a 152 in and see how it runs. But you shouldn't have any worries either way.

[Homerx]

Only one reply ?
:ermm:

[Mike594]

Hey, what size is the stock main jet anyway? 148?

[Homerx]

Stock is 148.

[DP400]

I just got a HMF slip-on, I have an 02 510 elevation and 15-30^F right now and I guess the carb on 99-03 are the same, change 04 and 05 and up, anyway I jetted mine and 40 pilot was to rich and backfiring in carb and when i opened it back up it smelled like gas. they also recomended and use a 165/170 main in their 400ex. right now i'm running stock pilot 2 3/4 turns out and 152 main. it seems fine but thats just riding around my 3/4 acre yard, minimal pop on decel down hill so i think it is ok.

[Homerx]

Originally posted by DP400
I just got a HMF slip-on, I have an 02 510 elevation and 15-30^F right now and I guess the carb on 99-03 are the same, change 04 and 05 and up, anyway I jetted mine and 40 pilot was to rich and backfiring in carb and when i opened it back up it smelled like gas. they also recomended and use a 165/170 main in their 400ex. right now i'm running stock pilot 2 3/4 turns out and 152 main. it seems fine but thats just riding around my 3/4 acre yard, minimal pop on decel down hill so i think it is ok.

WOW 165/170 seems rich even for winter. My concern is the cold, I know alot run 152/155 in the summer so I was thinking it may be a little lean for the winter here in the frozen north lol. Like I say I don't have a area to plug chop and want to head to some trails but don't want to burn it up. Been there done that on a two stroke. Do most guys typically up the main in the winter, if so by how many sizes 1,2,3 ?? Thx Guys

[sprayedgt]

A 165/170 is extremely too rich for a stock engine even with a open air box and full exhaust. You should go up 1 jet size in the winter. But it all depends on how your particular bike runs. No two are jetted the same given the same mods, temp, and elevation but close enough to get it in the ball park.

[Homerx]

Are there any other methods to check main jetting without doing "plug chop"?

[Homerx]

ttt

[BlasterEaten250]

Originally posted by Homerx
WOW 165/170 seems rich even for winter. It's probably a dynojet

[Homerx]

yeah I figured it must be, thats insane. Anyone else think I am ok with a 155 in 0 F weather . . that F**kin cold. thx

[BlasterEaten250]

That sounds about right.

[DP400]

HMF didn't tell me what jets they used but yeah could be different, and i thought not even knowing any better that was to high. I need to try and change to a 40 pilot still having trouble starting at stock pilot and getting poping on decel. They said not to change pilot though. when i was jetting was low on gas and couldn't get the quad to fire, could be why i flooded out with a higher pilot. also wanna change my main up to a 155k. running lid on though. still confused though?, but what a improvement over stock exhaust, i like the sound of the pipe but my neighbors don't, and they race 450mx bikes, and his is still louder, guess he's just jelous, that my quad doesn't sound like a turd anymore.

[Homerx]

Yeah, I don't think my nieghbors like mine either but they're both retired so hopefully thier hearing has gone LOL .