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Mostly Harmless
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Discussion Starter #1
Air Force Kit, eat your heart out!

Yesterday while out at Sand Mountain, I took the time to rejet and install my clamp-on K&N filter that I've had here for about a month. HOLY FREAKIN' CRAP! Tank about power! The top-end power now hits as hard as a 2-stroke, and midrange has gotten better too. I'm only at a 160 jet (4000' elevation) and I think I need to go up to a 165... sand drags are next weekend and I want to be ready for 'em!

I ran a guy on a Predator with the WB pipe, drop-in K&N and stock sprockets (I'm running 13/38). I've run Predators like that before and put, oh, 3-4 lengths on 'em. I ran this guy twice and put over EIGHT lengths on him! No joke, no exaggeration.

What's interesting is that the last time I was out there, when I was equipped with the drop-in filter, I ran against a guy with the Air Force kit, but with otherwise the same mods, including the sprockets. We even weighed about the same. Ran him twice and we TIED BOTH TIMES. That tells me the Air Force kit isn't really doing anything for top-end power. It may help midrange, but it sure isn't showing in real world testing.

Oh, and when I ran against that guy, he was on Haulers and I was on my Sand Skates. If I had had my Haulers on at the time, I probably would have beat him.

Edit: I will dig up the part numbers and post them later, along with who stocks 'em.

Rob
 

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Hey Rob, I've got to echo those results. Was out this weekend doing some jetting runs and other product testing....that filter does wake things up. I think Heapster and some others were running the RU-1770, I just raided the RU-1760 from my Sport. Which are you running? I'm thinking as long as the space is there, I'll opt for the 1770. Also, double check your low end, I think JJ was commenting about stepping up to a #50 pilot, and after this weekends results, I have one on order.
 

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rob the air force kit realy worked well for me. i was disappointed at first but after playing with the needle and jets created a moster everbody thinks i done engine mods. i can all so put eight to ten bike lenths on other predator and raptors on flat soft dirt.
 

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I found a place online that sells the K&N clamp on filter (RU-1770) that fits the Predator for $23.95. Thats about $15 cheaper than anywhere else I have found. They also have the Outerwears cover for it for another $10. The place is HyperRacing.com Give them a call if you are looking for a good deal on this filter. They were very cool and helpful when i called to order mine.
 

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Mostly Harmless
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Discussion Starter #5
I'm running the RU-1770. Thanks to LocalBuzz for posting the part numbers and an even cheaper place to get it than where I did.

Now to find out where to easily get those pilot jets...

Rob
 

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Also a thanks to Local Buzz. Rob, while ordering today, even using the "revised" jet part #'s from the Pred serv. manual, found out those have been changed again. You pretty much have to call Polaris. I suppose Carb Parts Warehouse, or Dennis Kirk would have them...even Mikuni.
 

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Localbuzz...I wanna see about the clamp on, but I can hit water now and then. I don't run through it, just motor along to get to the other side. Never deeper than the pegs. Oh yea...what is the Outerwears cover?
Do you have to come up w/ some kind of coupling to mate it to the carb?
 

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I got my clamp on filters from Hyper as well. However, the outerwears I bought from them were NOT the waterproof kind. Make sure the part number is WR125-6T. You can get them from Outerwears web site, I did and I'm real happy with the service. Actually, I traded the ones I got from Hyper. I thought Outerwears were great to let me do that. Hyper treated me well also.

Scott
 

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Mostly Harmless
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Discussion Starter #9
Ken... can you post the part numbers for the new jets and stuff? I was going to pull my pilot jet out tomorrow and take it to the local ATV parts store to see if they could match it up to anything.

What exactly does the pilot jet do, anyway? Also, did you have to adjust your needle height with the new filter?

Rob
 

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Kevin,
I don't plan on using the clamp on if i even think i will be near water. I don't even really trust the Outerwears covers that are waterproof. I will only be using the clamp on filter in the Dunes and on dry track race days.

The filter comes with the clamp that you need to attach it to your carb. The filter just slips onto the carb where the airbox part normally would go. then you jsut tighten down the clamp. its just that simple. I would re-jet before putting the filter in place. its easier to get to the jet with the filter off. The Outerwears cover is a cover tht slips over the filter that will keep out dirt, sand and most water(if you get the water proof one) You are probably fine running that filter with the water proof outerwear as ong as you don't submerge or subject it to large amounts of water. The outerwears will protect against splashes and and such. Its a must have if you plan on using this clamp on filter. I actually take a zip tie and tie down the end of the outerwears so that it has no chance of ever just coming off or letting in sand or dirt on that end. just an added precaution i take.
 

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On most carbs, your main jet is used from 3/4 the full throttle, the pilot jet is for 1/4 to 3/4 and the air screw adjusts from idle to 1/4 throttle. I am not sure on this carb, but thats what a chart that I have for the carbs on my banshee states.
 

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I'm still learning this jetting stuff. Is there anywhere that I could go and find out how to rejet mine? Also, what jet is stock, and what would be recommended for mine if the clamp on was my only mod? I don't have any intention of putting a pipe on it. Appreciate the help.

Scott
 

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Discussion Starter #13
If you're not going to pipe it, don't bother with the filter either. The mods go hand in hand. When you put more air into the motor, you have to be able to get the exhaust out.

Rob
 

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To be honest, I was putting the clamp on on more cause I like the K/N filter, and less to get a power increase. Is that just silly, or what? I really don't want to create a problem, and if this is going to, I guess I'll find another way to go.

Maybe I'm just ignorant about the pipe, but I do not want anything louder than what I have on it. I'm not one to make people riding behind have to endure the sound. So I guess my questions are these: If I just want to run the K/N, just because I think it's better, is it stupid to do so without running a different exhaust? And if I do, do I really need to rejet?

Thanks

Scott
 

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If you just want to run the k/n filter you still will need to re-jet. Any time you increase air flow, either in or out, re jetting will be required.
 

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Actually the Water Resistant Outerwear will take quite a bit of splashing. I've been running one on the modded Sport for a couple of years now. There is a huge difference between that and a regular Outerwear....those won't take splashing at all. I'll get the jet numbers later today....didn't write them down, sorry. If you want a step by step on rejetting, I did a post on atv connection, I'll go over and bump it to the top. Honest Rob, I'll start posting more of that info here...sorry to be a pain.
 

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Thanks Ken. Could you recommend the correct jet to use, with only the clamp on as a modification? Or, better yet, could you drive to either Michigan or Tennessee and do it for me? LOL.

Scott
 

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Discussion Starter #18
If all you want is the K&N filter, just get the drop-in. Then you're totally protected from water.

As for the pipe... the WB pipe is louder, but not that much louder. I got to hear several 100% stock Predators and some piped ones on Saturday, and the sound is difference, but the sound volume isn't that great. As long as you keep the spark arrestor on it, you'll be fine. I've followed plenty of piped machines and as long as the end cap is in place, the sound level is fine.

Rob
 

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Scott, with only the filter being added, probably a safe starting point would at least be a 160 main. As always, do a jetting check, just to be safe though.
The new Polaris # for the 170 main is 3130096, and the new 50 pilot is 3131021. Don't have my manual with me to double check, but they said they're different. That was the info straight from Polaris as of yesterday.

I've got to second Rob's comments on the W/B silencer, you can really tone this thing down if you want. Then again you can really thunder too, but that closes down riding areas...unless you're at a sanctioned race.
 

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How's the bottom end with the clamp on K&N? Is it improved over stock? Is it better or worse than airbox mods (for bottom end)? I know the top end rocks but it seems like some bottom end power would be really nice. Thanks in advance.
 
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