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K&N Filters Re-jetting

Posted: Mon Mar 15, 2010 8:16 pm
by tommytucker
Hi everyone, I've decided to replace the standard air box on my 3en1 with four K&N cone filters and wondered if anybody knew what size main jets to use. The bike starts up fine but is searching for fuel at about 50mph (1/4 to 1/2 throttle). The bike currently has 92.5 size jets and i understand that K&N recommend upjetting between 10 and 15%. Just wondered if any racers had found the optimum size jet???
Many thanks for any assistance given on this matter, Chris

Re: K&N Filters Re-jetting

Posted: Mon Mar 15, 2010 8:44 pm
by bendy3
I rekon you need to be around 110 main jet. Better off getting it run up on a dyno to get it spot on.

Re: K&N Filters Re-jetting

Posted: Wed Mar 17, 2010 7:37 am
by tommytucker
Cheers Bendy - found a dyno centre not too far from home, reckon i'll take your advice to get it spot on

Re: K&N Filters Re-jetting

Posted: Wed Mar 17, 2010 9:11 am
by Kayla
tommytucker wrote:The bike starts up fine but is searching for fuel at about 50mph (1/4 to 1/2 throttle).
Did you alter the needle heights at all? Try moving the needles up one notch (ie, move the clip down the needle to richen the mixture) and see what happens. It's free to try and easy to go back. I'm interested in what you find as I'm thinking about using foam filters on my 3EN1 too :)