How many of you guys have put a K & N air filter in your bike? I had one in my F4i and didn't really notice that much of a difference. What do you think about this?

 

i have one in my f4i and i dont notice a real power gain but i am getting about 10mpg more than stock (unless im gettin on it hard then the mpg is sparratic). it makes more of a diff when there are more parts added to create more and or better flow ie exhaust, jetting(carb), or power commander.

 

You will not personally feel or in any other way notice a difference. In most scenarios, there is none. The only time you need a high-flow air filter is when you've done airflow mods to your bike that eventually push so much air through the engine that your actual filter becomes the bottleneck, and begins to not provide the optimal air\fuel ratio. Even with a full race exhaust, the filter only becomes a bottleneck at very high speeds, when the DAI system is pushing some serious cubic feet of air through, just from sheer force. Even THEN, you're only going to gain like 2HP at best from a filter swap. Is it a cheap\easy 2HP? Sure. Will you physically feel it? Nope. The only time a high-flow filter is NECESSARY to functionality is with turbo-boosted bikes which again is a mod you would have to do yourself, as no stock CBR comes like that.

As far as the MPG gain goes, that's going to vary heavily by bike and riding style. Allowing the natural engine vacuum to suck in more air causes the bike to inject less fuel into the cylinder (more oxygen = more combustion, which means less fuel is needed to attain the necessary force). Getting 10MPG over stock is extreme impressive, but I'm not going to call shenanigans on James's statement. It's possible, given several circumstances are met. His larger bore and cams allow for more oxygen to be present in the first place, but also more fuel. He clearly has his power commander very well-tuned for milage (which in itself is an art).

The DOWNSIDE to high-flow filters is that they don't filter as well, thus allowing more debris to potentially enter the cylinders and decrease engine life.

This is a hotly contested issue, and I anticipate no less than 6 responses from people calling me a godless baby murderer. Ready? Go!

 

thanks for your input.

 

I have been running K&N filters on my bikes since the late eightys. The biggest benefit is that they are washable and reduce the cost of maintaining the bike long term. Any claimed performance gains are a bonus.
The gains are negligable without a pipe and rejetting on carbed bikes or a power commander on a fuelie.

 

have one on my f4. i am getting better mileage too. i was getting like 30-35. got one for xmas.

the only reason i know i get more is cause i left my debit card at home on accident one day when i was going to the college. i made it from my house to town(realize i forgot it, to school and back home all with the low gas light on. it figured out to be around 48 mpg. granted i thought i was going to run out so i didn't accelerate quite as hard as usual but not enough to justify the jump is mpg.

40 bucks for a little added protection from a name brand sounds like a good deal to me.

 

GODLESS BABY MURDERER!

Biggest benefit I see to running a K&N on the majority of our setups: reusable.

The guys that need high flow air filters is cause of what you said: they've done so much other chit to their bikes, the filter becomes a bottleneck

 

Yeah, godless baby murderer!

I use the K&Ns or their equivalents on all my machines; they are a good first step. Throttle response generally is a little more crisp.

 

sure, why not:GODLESS BABY MURDERER!