Athena Big Bore kit fuelling problem



  • Recently fitted the Athena 170 big bore kit onto my 2005 DT SM/R. Worked beautifully for the first two or three days and now struggles to run. Feels as if there is too much air in the mixture/not enough fuel. Tried the obvious fixes e.g. carb clean, increasing tickover etc. Runs fine with the choke on/whilst using the throttle but cuts out as soon as it’s idling. Anybody else experienced similar issues and have any ideas as to what it could be?



  • Did you rejet or adjust the carb to suit the big bore kit?



  • Yeah there was definitely a rejet carried out



  • What's the spark plug look like? Have you checked/cleaned the air filter? Is the exhaust blowing?



  • Yeah the spark plug is fine, air filter has been done recently and it’s had a new expansion chamber so the exhaust is also fine



  • Take the exhaust off and have a ganders up the port. Make sure the piston crown, rings and skirt aren't damaged.

    In my experience, the Athena kit was pretty bullet proof.



  • Managed to find it, extremely small split in the inlet manifold so it was pulling extra air into the engine. Thanks for all the help though guys!!


Log in to reply