Athena Big Bore kit fuelling problem

[emiljay]

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?

[finnerz89]

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

[emiljay]

Yeah there was definitely a rejet carried out

[finnerz89]

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

[emiljay]

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

[Calum]

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.

[emiljay]

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!!