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CBR250RR (MC22) backfiring

Discussion in 'Maintenance and Servicing' started by BlackSparrow, Feb 16, 2016.

  1. My MC22 backfires occasionally when taking it for a spirited ride up the old pacific hwy. Typically this happens when settling into corners and holding revs in the top end range. Sounds like its popping out from the exhaust.

    Should i be concerned? Does this indicate a rich mix? Is there anything to check? Temps look good and it doesn't happen when commuting around town.

  2. What's the service history like? Clean you carburettor, change spark plugs and put in some fresh fuel.

    If this doesn't fix it then look at your valve adjustments and also your spark plug leads(coils).

    Backfire when decelerating is quite common especially if you have a slip on, however under acceleration could be a variety of issues. Good luck.
  3. Thanks Bugz.
    Had a major service/full fluids change done on it when i bought it in November - looked after it pretty carefully since then. They checked valve clearances and apparently their within limits. I did remove the tank to replace the idle adjustment screw a while back and flooded it when trying to start it back up - perhaps fouled plugs from that? Ill check them out.
  4. Exhaust leak?
  5. Sounds crazy, but check your coils are going to the right plugs. Also check your air filter has a proper seal and is oiled well if it isn't a paper type as this was causing issues with my zxr running lean and backfiring on acceleration. Pull your plugs and check them, if they're fouled just clean them lightly with some fine sandpaper, or obviously buy new ones..

    If it is popping in the exhaust and not backfiring back up through the carb/airbox then it could just be condensation in the exhaust or running too rich.
  6. I think this post will have some useful info, scroll down to the bit that's titled "Burn Baby Burn" if you're in a hurry, then go back and read the whole post.