More K&N fun

I’m still trying to get the K&N to work at low RPMs because I’ve tasted the increase in performance at high RPMs and I liked it. I first tried cutting the yogurt cup down by about half an inch, since this reduced the diameter of the lip it reduced the height of the cup inside the cone tremendously. Before the lip of the cup was resting on the pleats and the bottom of the cup was flush with the opening of the cone. With the cup cut so the outside diameter of the lip was exactly the same as the inside diameter of the bottom of the cone the bottom of the cup sat about 3″ below the opening of the cone.

Continue reading “More K&N fun”

K&N filter upgrade with yogurt cup modification

I bought a K&N filter for my 700. I’ve had K&N filters on all of my vehicles and never had an issue. However on the 700 its freer flowing ways make the engine run lean. Following a tip from a friend I looked for something to reduce the volume of the filter and ended up with an upside-down yogurt cup inside the cone filter. This should reduce the volume of air, increase the speed, lower the pressure, and help the fuel atomize. The yogurt cup definitely helped the performance of the K&N. Without it it barely starts and sputters and pops and won’t climb above 4grand. Once the cup is in place it will climb ok, but the exhaust still sounds “hollow” for lack of a better word and will backfire between 4500 and 5000 rpm. Once you get it past 5000 rpm it takes off and you better be holding on tight.

So I need to tweak my yogurt cup, or mebbe fiddle with the slow-speed jets…

An audio file of the exhaust note with K&N and yogurt cup installed can be heard here. The beginning of the file is at 2K rpm, the next step up is 3K, then up to 4K where you can begin to hear popping all the way up to 5K. The rev after that went straight to 8K with no resistance.