Man!!! I have read 14,000,000 posts on this already and still can't seem to get it dialed in. I have a FMF power core 4sq slip-on and cut the flaps out of the snorkle. I put in a new plug and did 5-6 full throttle plug tests. The ceramic portion of my plug is still white. I am using 150/155 mains and 27.5 pilots. I just can't imagine that I need to go bigger with just a slip-on. I have noticed that when running full throttle and letting off (far a second) and hitting full again, it pops and then goes again. This is a lean condition. Isn't it? I have checked the clip position and it is in the 3rd from the top position. I can't imagine that I should need to go bigger or move the clip. Anyone with thoughts? Your help is appreciated.
Thanks for answering the 14,000,001 jetting question.

 

I am surprised you had to do anything at all with just the slip on. I am also looking at the FMF slip on. Keep us posted.

 

I have yet to mess with my clip position or mixture screw and mine is running great.I think the Raptor is lean form the factory. I put 150,155 jets in mine with no mods at all and it smoothed it out a lot and even picked it up some, so you might still be on the lean side.And also, start jetting to high and work your way down, this saves a lot of time.Try a 160,165.That is the most you should need, then work your way down.

 

It's removing the snorkel flaps, not the silencer that causes it to lean out so much.

 

Bash, it's hard to believe just those two flap removals would cause us to have to re-jet. Ahhhh...I better check my plug.

 

I have a question? When you are gasing it and let off and it pops, doesn't that mean it's rich. I say this because I recently ran from about 1,500 to 6,700 feet. When I got higher the air gets thinner, the engine is running richer. Let me tell you it was poping alot. I might be wrong, can someone varify this.

Thx,

 

Swytak I ride at 4800ft and am running 145 and 150, clip in number four position, w/ full Big Gun, holes in air box and flaps cut out. You need to go up on your jetting beacuse you are alot lower then us. My brother tried a 150 and 155, ran to rich.

 

I tend to believe the popping comes from a rich condition as you have noticed. I ran my mains all the way up to 200 before it actually cut out and fouled the plug.. But it was way rich. It seemed to me the richer I got it the more mid it has but I lost the top. Mine felt like 5th gear was an overdrive. I started back down until I felt 5th gear really pulling hard and stopped.

I have a feeling that most of the jetting going on is way on the rich side. Time will tell. When I had the lid on and full exhaust I ran 150/155 and it felt okay but looking back I think it was rich. It seemed like it coasted in 5th.

 

Thanks fella's, I just picked up 160,165 and 170 mains. Will install and test tonight. Also picked up 6 1" univents for the lid. So if I can get it rich enough with 165/170 I will install the uni's. Let ya know tomorrow.
Thanks for the help.

 

Question...before taking my carbs off, what style of jets does the Raptor have? My brilliant Yamaha counter clown didn't know!!! Round or hex??

thanks