I did a plug chop / choke test, and the spark plugs are looking a bit lean (pics attached), so it seems I need to step up the main jet size. Engine runs to 10-11k rpms. Or dashboard is false, but its sound like F1.. video later Current Carb Specs: Idle / Pilot jet: 25 (stock) Main jet: 160 Needle clip: Middle position Engine & Setup Modifications: Exhaust: DG exhaust system Cylinders: Raised by 1 mm (thicker base gasket) Compression: Increased compression ratio (decked/machined both top of cylinders and heads) Porting / Prep: Smoothed out and blend-chamfered all sharp edges around the bottom ports