K&N air filter mod

[Zach214]

I just bought a K&N air filter and want to run it with the air box off. I was wondering what size jet I should have so I don't blow my engine. My Quad is board .50 over and I have a FMF fatty pipe with a FMF powercore 2 silencer. I am running a 270 jet right now. What size jet should I have?

 

[82cutty]

Pre-mix too ? Start with a 300 and do a plug chop if you are . Most people with your mods are in the 280-290 area . I was a bit rich with a 290 with similar mods .

 

[Herpderplol]

i would buy 280-310 and start high.

any particular reason you went K&N? what type of riding do you do?

the reason i ask is because K&N filter will fail if they get wet. they also let more dust/dirt through.

 

[Zach214]

I went with a K&N because I heard they were good. I ride in my yard and racetracks.

 

[Zach214]

If I switched back to my foam UNI filter but wanted to run with the air box off would the jet sizes you posted above still be correct?

 

[Herpderplol]

yeh, probably around 290-300. make sure you plug chop

 

[Zach214]

Why do I have to Plug chop?

 

[Herpderplol]

To know 100% that your jetting is right. we can only give you suggestions. all engine are different. climates are different etc