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Discussion Starter #1 (Edited)
Jetting that works for my setup help!

My Raptor is not running right and i am pretty sure its a jetting issue since it ran pretty dam good stock before I got to it. This is whats on the atv right now.

Illinois
Dyno Jet needles at the 3rd notch
DJ 170-175R
Mikuni 27.5 mains
Open air box no lid with a K&N filter and outerware as in my pic
Full Curtis Sparks exhaust
About 2 1/2 turns on the fuel mixture screws
 

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Discussion Starter #2
bump
 

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Master of the Electron
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You need to describe HOW your bike is not running right... what does it do, under what throttle conditions, etc... then you will get tons of suggestions.
 

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Discussion Starter #4 (Edited)
You need to describe HOW your bike is not running right... what does it do, under what throttle conditions, etc... then you will get tons of suggestions.
Ok I haven’t had a chance to really ride it since I can do it here where I live I would have to go pretty far to ride it. But at Idle it idles fine but as soon as I rev it to wot it pops and hesitates and then it will rev up shoot a flame and then a puff of black smoke and it will rev to the moon. Hope this helps
 

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Master of the Electron
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What did you change? ("ran good stock before I got to it") If you modified the exhaust or intake you're going to need to rejet. Tell us what you have, mods wise, and we'll tell you a good place to start with the jetting.
 

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Discussion Starter #6
What did you change? ("ran good stock before I got to it") If you modified the exhaust or intake you're going to need to rejet. Tell us what you have, mods wise, and we'll tell you a good place to start with the jetting.
I went from a great running complete stock Raptor to this. As far as the DJ 170-175R jets thats what DJ told me to use.

Illinois
Dyno Jet needles at the 3rd notch
DJ 170-175R
Mikuni 27.5 mains
Open air box no lid with a K&N filter and outerware as in my pic
Full Curtis Sparks exhaust
About 2 1/2 turns on the fuel mixture screws
 

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Master of the Electron
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14,490 Posts
Those mains sound high to me - DJ's are significantly larger than Mikuni's for the same number...

For your mods, I'd be thinking 165-170 or 170-175 Mikuni's. DJ's would need to be smaller - in the 150-160's area, i think, but I'm not an expert at the cross referencing.

Your 27.5's are the pilot jets, not mains as stated.

Just for a quick test, the stumbling is only at mid throttle, so I'd try leaning out the needles a bit. Try dropping the needles (raising the clips) one or two notches... see if things get better. I'm assuming you're too rich here... but if things get worse, then try moving the needles the other way. It's at least an easy thing to try before getting into jet changes.

Here's an example with similar mods using DJ jetting: http://www.raptorforum.com/forums/showpost.php?p=797813&postcount=22

You may want to be a bit richer, but not too much.
 
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