Do I need to rejet with a header replacement?


New Member
I have an 01 fz1 I just got a few months back and have a faulty exup system (rattling at idle and irregular changing exhaust note and surging when cruising). I'm going to install the black widow downpipes and get rid of the exup system entirely, but am concerned about the need for rejetting. Is there anyone who knows if it would be required? I really don't want to mess with the carbs right now and would rather just try to fix the exup system if a rejet would beneeded
Last edited:

jared p

You can just safety wire the exup open, disconnect the cables, leave the motor in so it doesn't trip a code. It's not needed for performance but rathe remissions. Headers will require new jetting.