What is the clean air mod on a F4I?
 

title says it all

You replace the pair valve with a T

i'm not following

lol

hmmmm did a search on it and . the guy who answered the thread said its bad for the bike ???? i would like to hear about it as well..

Nope, it's not bad. Most popular mod for stunters. It get rids of the backfiring with slip ons at high rpm decels. Makes the bike run better in the lower rpms and doesn't hurt anything at all. It's a emmissions crap tee sending unburnt a/f back in the motor (emissions crap)

What I did was same as the write up, capped the 2 large ports on the airbox but Didn't buy a tee... No need too. You take the PAIR valve and unscrew it, you can take the center spring valve out, put the screws back in as there is rubber o-rings to seal the tee and hook your 3 large lines up as you toss away the longest large vac hose that feeds from the valve to rear port of the airbox. Super easy and no need for a $2 tee. It's DYNO proven mod and been around for 10+ years... Find me a proven article on why its bad... I did my 2 days of reading and research. Found no negatives.

Google:
About 16,500 results (0.07 seconds)
how to air box mod f4i - Stunt Bike Forum

note: #4 goes to the bottom of the "T". NOT #3

Attachment 48990

dang...I'm gonna have to pull my tank and air box again...though maybe it was already done (since my bike doesn't backfire at all)...but i think those hoses are all still there.

Too bad I forgot to check it when I changed my throttle tube out.

thanks for that awesome pic explaining it all:icon_google:

Is this on every bike or only California bikes?