Kleen Air System

Whilst doing the valve clearances I noticed this plumbing.

Online chatter & a local ZX10R owner suggests its emissions related and may also contribute to the 4k rpm backfire on down throttle.

brocksperformance.ca have a simple plug that blocks the tube into the airbox as opposed to some who remove the whole kaboodle from the cylinder head cover.  Seems a resistor may be needed here to fool the ECU..

So I blocked off the Air box hole and the tube from the air switch per the brock performance instructions and it still back fires..