ATV Florida Forum

Hey fellas, I cannot get my bike to stop breakin up on the top end at all. I have went through every size jet / needle / combination you can possibly think of and it still breaks up.

I have an 09' Foreman and its snorkled with an 1-1/2" pipe out of the box and the a 2" pipe that turns up and out the front of the bike. We have tried everything....we even ran it without the air box lid to see if we were starving it of air and it still does it.

I have a HMF Slipon pipe, k&n filter and outer wear, dynojet kit, and snorkled...I guess my next option is to find a shop with a Dyno machine to put it on and tell me whats going on with it.

Does anyone know of anybody that can "SOLVE" my breakin up issue? Are there any shops here in Flroida with a Dyno?

HELLLLLLLLLLLLLLLLLLLLLLLLLLLLLLP!

performanceatvracing.com in Miami has a dyno, ask for ray 305 235-3880

how much inch and half pipe u got?? right out air box needs to be 2inch pipe   i belive last honda i jetted like that needle was on 3rd clip and it was a 165 main jet

I have an 1-1/2" that comes out of the air box all the way to the front under the headlight and then goes into a 2" pipe up and out the front.
I also have the flex pipe going over the top of my carb and then down the left hand side of my motor. Should this be ran straight from the airbox down the right side of my motor with a 2" pipe all the way? Now with that being said, the hole in my airbox is 1-1/2" do I use a reducer there and then go into a 2" pipe or should I modify the box and go into it with a 2" pipe?

oh by the way...its an 09' Foreman if that matters.

Walsh Race Craft in Live Oak

Awsome...thats alot closer than Miami...I am located in Jacksonville, Florida

thats your problem    get pipe out air box and as soon as u can u need to hit 2inch pipe     
 u are strangling the motor with that inch and half pipe to head light  change that to 2inch and i bet it will work perfect

Normally when you put on a snorkel, you force too much air into the airbox causing it to run lean. Too little air is probably not the problem. That is proven by the fact you take your lid off and it still persists.

Just for shiggles, try jetting it on the fact that the snorkel is creating more air. Might be a cheap fix.

Tell Mike at Walsh you are a member of the plex and he will look after you.  ;)

I agree he has a lack of fuel but with the HMF pipe he would also benefit from the 2" pipe . The dynojet kit may only be set for stock exhaust and air intake. I would call HMF and ask them their recommendation of jet size and needle setting for your altitude with their pipe and aftermarket filter( I bet it is much larger than what comes in the dynojet kit).

The dynojet kit stated a 170 jet, needle on the 3rd clip, and 2-1.2 turns out on the fuel mixture screw....did exactly that and still breaks up on the top end bad.  I read alot where people were changing out the main jet to a 48...did that and still the same thing. I am going to rework my snork soon with a 2" pipe and see what happens.
I am about ready to go back to stock and not have to deal with the headaches anymore!

do 2inch all way out u will not have any problems

Will do this weekend and letcha know what happens as soon as I get done.

you rock...still need alittle fine tuning but it is not breaking up anymore at all. I went 2" straight out of the airbox down the right sidehung a left and then a quick right, and then went straight up to the existing hile in front of the healight. Took it for a spin, no breakin up...the only thing is, the spark plug is blackish brown around the ring of the plug and the tip is kinda smokey / white...now this is with a 165 jet as the 170 that came with the kit is at my mechanics house but everything else is set to dynojet specs and I can tell ya, she runs 100% better than it was right now. Thanks to everyone for their input!!!!

no problem i may be an a hole on the site but i do no how to work on things good. glad to see u saved money on dyno

ok...throughout all of this mess; we changed out the main pilot jet from a 45 to a 48....now that its not breaking up, I have installed the dyno jet needle on the 3rd clip, tonight I am going to re-install the 170 jet, would you think that I need to change the main pilot jet back to the stock 45? Thanks ....

I think you should throw the dynojet jets in the trash, they are very confusing because there numbers are not the same as keihin jets. There is a conversion jet chart floating around the internet somewhere though, other than that they confuse people all the time.