This should answer your jetting issues with the Big Gun exhaust (and probably other aftermarkets as well)...

I picked up my Raptor last night from having it re-jetted (160/165 and 27.5s) and today after work I tried it out for the first time.

Not too happy!

It would pull hard but then start bogging at higher RPMs (kinda like you were letting off the gas and then back on again). I went home and called Paul at Big Gun. He asked me to pull the plug and call him back. I did and I told him the plug was a light gray in the center of the electrode but dark black around the outside diameter.

He said, "hum".

He then said we can figure this out once and for all. Pull the lid off the top of the air box and ride it down the street and call me back.

I did.

When I called him back, I asked him if he had liability insurance. He asked "why" and I proceeded to tell him when I shifted to 2nd and blipped the throttle I nearly went flat on my back.

He laughed and said "it's dialed in!"

So, in summary...

If you're anywhere near sea-level, the original recommendation (150/155 and 27.5s) should be dead on if you use the stock filter and box.

HOWEVER, if you go richer (like 160/165) you'll need more air and since most people plan on going with an aftermarket filter and/or air box modifications, then this should be your setting.

Hope this helps!

As a side note, for those of you with a Playstation2, invest in a 900 mhz cordless Mad Catz controller...it's sweeeeet!

 

So we are talking a HUGE difference now that you have the pipe and proper jetting?!

In addition to having more mojo in low gears, does it seem to pull longer/faster in high gear than stock? It'd be nice to have a top speed reading!

 

Ill back u on that one, I too have the Big Gun exhaust and am currently running the 150, 155, 27.5 setup, but with the stock filter setup. It seems to fall on its face in the higher RPMs, I ordered a 172.5 and a 177.5. I hope that this will not be to rich. Any thoughts? Oh by the way, i went up 1 tooth on my front sprocket and the bike picked up 1.8 mph on the top end. It even smoked a stock geared Raptor in a short drag race, he jumped out to an eairly lead, but by the time i hit third gear i was pasing him, i had him by 2 bike lengts by the time we were both reved out in 5th

 

bash,

I would say YES, there is a significant difference in the low end. However, since I was just testing this in a residential neighborhood, I did not experience any of the high RPMs in the higher gears. That should come this weekend.

I kid you not, 2nd gear now seems to lift as easy as 1st gear did stock and 1st gear now lifts ridiculously EASY!

 

No2StrokeBs,

I would think your suggested jetting may be a little rich, however, I'm not sure what your elevation is. If you don't change your filter or box setup I can almost guarantee it will be too rich.

 

I have Pro Design Filter with the BG Complete exhaust and 175/180 is too rich even with no airbox cover. I am in MAine and the curretn temp is 34 degrees. Tomorrow I will put in the 165/170 - with the air this dense I think I have too. Funny thing ---- my buddy screwed with me when I went to test it with no air box cover --- he turned the fuel off so I thought I cooked it for sure - I thought to myself "Damn , Now I have to put all the stock parts back on and take it to the dealer" then he comes riding up in his truck and says "you didn't cook it did you" like a dumb *** I say - yup. Anyway more tuning tomorrow - the neighbors are getting a little bent at me.

BJ

 

You should see the jerk that lives next to me! He HATES that "Yoshimura sound!" I don't care, because we don't get along anyway.

 

Yeah,

Funny that those jerk neighbors you NEVER see, always come stirring around when you're tuning, huh? The people I've not seen in two years seem pretty interested in my Pro Circuit exhaust...loud it is...I didn't get this much attention tuning my blown big block Camaro! Ride Out Guys!

 

I am currently jetting my raptor,
yoshimura titanium full race exhaust
pro design kit
removed snorkel

160/165 and 27.5 pilots TOO RICH!
ran better with 150/155 but needs to be a bit richer, thank god I ordered $75 worth of jets from sudco. Possibly 152.5/157.5 and 27.5 pilots for me. (thinking of going back to factory pilots)

my plug seems black as hell on the outside and kinda lighter on the tip/ any ideas?

 

dsEATER,

Your description of the spark plug tip sounds like mine. However, once I removed the air box lid it ran PERFECT. I would rather be a little rich than too lean.

It would seem that the 150/155 setup with air box lid removed would be too lean, which would explain why it runs better, just dangerous in the long run. What symptoms do you have (performance wise) with the 160/165 and air box lid removed?