The prefilter difference

Another Prefilter upgrade, I want to eliminate the Prefilter box and switch to K&N filters
so I can eliminate the leakage I have been getting around the foam panel filter without
modifying the filter box and making it over complicated also using the K&N as a Prefilter
I can wash the filters wile on the road .

Using some 2" muffler tubing and a strap of metal I fashioned a filter mounting bracket.

Note on K&N filters learn the FACTS about these filters before using them on ANYTHING don't believe the MFG's claims they can claim anything to sell a product then YOUR stuck paying the bill when you find out different, don't take my word for it take the test yourself, I use them for prefilters ONLY and only because of the ease of cleaning, I can clean them on the fly in my RV or in the bathroom sink at a gas station, to properly clean my foam filters it requires solvents and more time than I want to spend on a ride trip, here is my findings on the K&N Filter Central ((The Dirty Truth)) page viewtopic.php?f=1&t=5491

Modifying the lid to the air box is pretty simple using a hole saw and another piece of 2"muffler tubing, this picture gives you a good idea where to locate the second hole.

Update I have noticed many of the newer air box modification are cutting a single large hole in the air box then installing a single large air filter, while designs that vary from mine are fine and dandy I would like to point out the reasons why my design is like it is and has a proven track record under ALL operating conditions, read on

I use two filters and two holes for a reason, one is for fit and finish, two smaller tubes relocating the air intake to cleaner cooler air is easier than using one large tube, it also allows me to IMO properly position my prefilters where they can be the most effective, first lets discuss the dirt, NO filter is 100% that means it will pass dirt, as the filter loads up with dirt the dirt is beat, blown, sucked and bounced to the inside if the filter, what you don't want inside your filter gets their by mounting my prefilters horizontally like I do the dirt that has made it pass the prefilter falls to the bottom of the filter and little to none of this dirt works its way down the tube to the main filter in the air box.

Next look at my design what happens when your riding in the rain or caught in a downpour well with my design you keep riding water will not work its way into the air box it will run through the filter then drain out.

I jet my Pilot, set it and forget it, I ride from 0 feet to 6000' elevation , from 50 degrees to 85 degrees with the same jetting on colder drier days I will put a piece of duct tape on the inside of the air box blocking off one of the intake openings this changes my jetting from idle to WOT (Wide Open Throttle) enough where I don't have to go inside my carb and change jets and make needle adjustments.

Consider these when making your design choice.

Here are the filters getting ready to be washed in preparation for the next ride.


My second generation pre filter design is working out good, I guess I bought large enough
filters and they provide enough filter service area, even when they got as dirty as you see
in the above pictures my jetting was not affected enough to worry about changing pre filters

Now you can buy a fiberglass replica of my mod if you don't want to fabricate your own cover.

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http://pilotodyssey.com/PO/viewtopic.php?t=533" ."..

DC's Pre-Filter setup http://pilotodyssey.com/PO/viewtopic.php?t=1153

Here are some pics of the Wiggins Prefilter Mod Check it out. http://pilotodyssey.com/PO/viewtopic.php?t=1181

"H" Nice setups. Is there a reason you have not cut of the stock defletor cone on the first of two holes on original lid. I would think the static pressure from one tub to next would not be in balance causing turblance ( air flow at different pressures) in the air box. Granted the second tube would increase flow at a lower static pressure for a single carb. What about for a twin carbs. Maybe go 2.5 or 3", any thoughts. The pre filter ( set mounted by net) would a cruved deflection plate on the front side help with pleat infiltration. They seam to be postioned behind head. I know when drakman does a break check I duct the best I can and gas out of roost rang, that's a lot of sand hitting the twin prefilters. Does the added intake tract lenght seam to hurt mid pull off the bottom any. If so would a boost bootle on the primary air cleaner box help with throttle lag if any. I was going to try a setup for new darkart chaser Engine and would like some input. I'am like 5 alive, need more input. On your 250 does it have a boost bottle coming off the intake tract ? I do know, you say tape off or choke off to help on jetting however It's an air pump. Maybe a dial a jet would be better by regulation of fuel rather than air. I know why you do it though just get myself to do it . It's like a dirty air cleaner bad on preformance. Thanks for the help.

Check this out here is Stonemans filters after Casey race using the prefilter mod.

http://www.pilotodyssey.com/PO/viewtopic.php?t=4450&postdays=0&postorder=asc&start=24

Nice and clean, this is how you make engines last.