K&N filter: yes or no?

Hello fellow VTR'ers

I recently took delivery of a set of standard mount Micron oval (race, I believe) slip-ons and a Dynojet kit which I hope to install in the very near future (note: FYI following some calls directly to Dynojet, I was informed that the Dynojet jet kit is identical to the Micron jet kit sold for this pipe; same needles, springs,...). During the installation process, I will be disabling the PAIR system, adjusting the TPS and installing a long intake trumpet on the front cylinder (increase lows and mids). Based on info received from a well-known VTR tuner (Revolution Racing in the UK) I will not be drilling my slides (doesn't recommend it for a street bike). My big dilemma now is whether or not to invest in a K&N air filter. I essentially use the bike for sporty sport-touring and want more punch in the midrange (max. 7K rpm). I have been doing a lot of research in the matter of getting the K&N or keeping the stock filter in place and have been getting mixed messages with some claiming that (once properly jetted for of course) the K&N increases power across the rev band while others claim that it gives better top-end but at the expense of mid-range. Does anyone know for sure? I want to get this straightened out once and for all so I do not have to repeat the re-jetting process all over again for nothing. Again, I am mostly looking for extra punch in the mids and am not overly concerned with high-rpm power. Gaining 3 hp on top is not worth a 4 hp drop at 5K, it is really that simple.

On another note, I just got back from riding my 'Storm with the 43 teeth rear sprocket and I love it. I also shimmed the rear shock 4.5 mm and raised the forks 6 mm and the results are awesome (of course the shortened wheelbase from the larger rear sprocket also helps). These minor changes have transformed the bike. I am really looking forward to getting those pipes and jet kit on there. Woohoo!!!!

So, if anyone has experience comparing stock filter vs K&N (both properly jetted and with aftermarket pipes preferably) I would certainly welcome your input.

Cheers
Micky

Funny you should mention the intake stack. My well known VTR tuner friend did a TON of dyno work with the VTR. Change one thing, test it, change another, etc. He had me put the short stack on the rear for 1-2 HP on the top end. I did it before building the engine and the difference was not noticeable, but I'm sure it is true. He also experimented with airbox configuration and air filters. Everything he did to the stock airbox made it worse. The K&N filter did add top end power, but at the cost of a substantial hit in the midrange. Even at 130 RWHP, he raced with a stock air filter. He has talked me out of changing filters twice. Once with the stock motor and again with a built one.

Also, I'm very surprised to hear that he doesn't recommend drilling the slide, since it controls the rate of opening of the slides. With the softer spring and no drilling, it seems to me the slides would open too quickly and the engine will fall on its face. I drilled mine. The jetting works great on the street and the racetrack.


Modified by rc996 at 9:09 AM 5/8/2005

Cheers RC

This is exactly the type of info I was looking for. Looks like I will be staying with the stock filter.

IN regards to drilling the slide, here is the reply I got in relation to that very matter:
Drilling the slide increases the speed of lift of the slide, this aids
sudden acceleration (in fact there are two stages of slide drilling one
specifically for racing bikes)
Tthe UK Dynojet "stage one" kits contain only three sizes of jets and
one way to pass through a carburation "flat spot" is to pass throught more
quickly - disguise it in effect. I prefer to cure it with more refinement
than the standard UK kit will allow.
The jetting and all other settings are different if the bike is a
dedicated track or race bike rather than a "touring" bike.when you drill the
slide it is usually used in more severe situations than touring ie rapid and
extreme turns of the throttle both for acceleration and de-acceleration.
When touring you tend to use more constant thottle positions, under theses
circumstances the slide actually descends slightly from its orginal opening
lift position as the bike (and carb airspeed) "cruises "and settles. A
drilled slide will flutter more under these circumstances and could cause a
slight "pecking" affect.


Again, thanks for the info

Micky