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CB400 staintune upgrade popping sound

Discussion in 'Technical and Troubleshooting Torque' started by ngalbrai, Jan 17, 2012.

  1. Hi, upgraded standard exhaust on CB400 with staintune, sounds great but notice a bit of popping when I close off the throttle - is that normal or does it mean the fuel/air mixture not right?

    Should some timing changes have been made with the change of pipe? Had it done at Action in the city so assume all done correctly?


  2. fuel air/mixture wrong,
    (assuming its carby) i would put my money on it being the jetting.
    it doesnt matter what pipe you change to, but any intake/exhaust mods need jetting done.

    if its EFI. then you need a power commander (piggyback ecu) and an dyno.
  3. TRUE..............but as an addition.

    If EFI - there maybe a lambda sensor in the mid pipe which is making things lean out...........normally due to a PAIR valve siphoning "fresh" air from the air box....simple (and cheap mod) to fix the popping if this is the case
  4. Thanks guys, will call Action.
  5. don't worry about it
    its just the weasels
    • Funny Funny x 1
  6. Nice system had one on mine and loved it. Always had a bit of a cackle on deceleration but not popping or banging, rode with baffle out. Mine was on the bike when I got it so I can't tell you wether it had been retuned or not.
    As said above check with the supplier.
  7. Hahaha, just got that, most amusing :ROFLMAO: