If it wont go to the set postion...

Start the engine, blip it to just over 3000 rpm and mark the servo motor where the pully wheel pointer goes too (it wont go as far as the HI mark on the servo body).

Stop the engine and turn the servo pully to this new mark. This is now full open.

Take the exhaust off and adjust teh cables so the power valve flaps are just recessed inside the roof of teh exhast port (0.2-0.3mm).

Button it all back up and away you go.

Do not use the marks on the barrels as these will now mean nothing. You are now setting it up, servo full open-valve full open.
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If I have to take the carbs off once more...