Bike Runs Horrid after K&N

[Radd]

Bike ran fine before I started replacing the fairings. While i was in there i figured i would replace the air filter with the K&N. Removed the stock air box and put the new filters on. Tried to start the bike and it ran like Garbage! Won't rev out for beans! I have to move the black slide thing up to get it to rev. I checked the diaphram on the top of the carb and one is ripped a bit. Could this cause it to run ****ty like this? Its been jetted from a 17 to a 27 whatever that means. The previous owner did this work to it. It has a D&D exhaust on it too. The air line that goes into the stock box does it need to go to anything?

Possibly useless info: I can get it to rev out by taking the to lines off the top of the carbs and shoving them into the pcv hose.

[strn365]

TAKE THE K&N's off the katanas dont like them at all. Please use the search function.

[steves]

Yes. Put the airbox back on.

K&N Pod filters are notoriously difficult to tune correctly.

[suzukiray]

You cannot just remove the airbox, stick a set of K&Ns on & expect the bike to run well! You have leaned the fuel mixture drastically & need to richen up the fuel. A lot of people on here have problems tuning their bikes with individual filters but I don't have a problem with them. I've also been jetting them for 30 years & know what to look for. For an inexperienced tuner it may be difficult. Ray.

[HexKrak]

K&N will be hard to tune on any CV (constant velocity) carburetors, such as the ones on your katana unless (and sometimes even if) you're an experienced bike tuner. Admittedly searching for K&N will result with an error (as you must have 4 letters minimum), but you can find threads detailing the issue in the hundreds by searching air filter.

[katman05]

Save yourself the headache and put the stock filter back on.

[DOCTORNITRO]

Where's "you-know-who" when ya need him? LOL

[ct3]

that sucks!

[md86]

Plus the torn diaphragm ain't helping matters any ......

[GregS]

Plus the torn diaphragm ain't helping matters any ......

Thank you MD for pointing that out. While the pod K&N's generally will not run as well as the stock box, they will NOT cause the type of run problem mentioned.
Read the entire story and you'll find not only a torn diaphragm mentioned but also vacuum lines and breather lines not properly installed.

[rockin6d]

i put a K&N inside my stock air box and still had to downsize the airbox opening. wouldn't run below 4k until i did.

[GregS]

wouldn't run below 4k until i did.

Does this mean it died below 4K? Or did it just not have the power and response as before? Likely it just ran poorly, not what the original post is referring to.
Exaggerations like "wouldn't run" are making diagnosis of a problem impossible. If it really "wouldn't run" below 4K then it wouldn't even start since your starter can't turn the engine over at 4K.
OK, I'm stepping off the box for now.

[baddkat]

Where's "you-know-who" when ya need him? LOL

[rockin6d]

Does this mean it died below 4K? Or did it just not have the power and response as before? Likely it just ran poorly, not what the original post is referring to.
Exaggerations like "wouldn't run" are making diagnosis of a problem impossible. If it really "wouldn't run" below 4K then it wouldn't even start since your starter can't turn the engine over at 4K.
OK, I'm stepping off the box for now.

just like i said wouldn't run below 4k. Give a little throttle, accel pump gives enough gas to start. Either i had to hold the throttle open wide enough to stay above 4k or the engine would die when the fuel mix got to lean to support combustion. If you don't know that starting and running are two different things then go see mr webster. And for future reference I DO say what i mean and mean what i say, this however is not to be confused with being right or wrong, the definition of that difference i leave up to my wife.

[katitoy]

Put back the stock airbox. I bought my bike with K&N (runs and idles rough). I replaced it with stock. Performance improved a lot.