Whew... I've removed and installed this carb 4 times today! 1) Corrected the float level 2) drilled the crossbeam idle restriction from .07 to .08" 3) drilled the upper idle port to .04" (it was probably ~.03" to start) 4) drilled the middle idle port to .052 from .043" (idle ports shown in Jon G's picture attached)
Each time I test drove while watching the mixture gauge and it seems like nothing changed! I was hoping to enrich the mixture at times when throttle is slightly above idle to make the clutch more beginner friendly on uphill starts. 2nd gear starts (in the 420 trans) need all the help they can get to start rolling my 32" tires and 3.38 gears. Attached is a graph of the mixture behavior when I get rolling.
Tomorrow, I'm thinking about drilling even bigger on the crossbeam restrictor... but am starting to wonder if the real reason it's tough to get rolling is a limitation of the accelerator pump at light throttle? It's the kind without an intake check ball, just a gap in the upper stroke for the float bowl to slosh in. However, the presence of the extra-lean cruise plateau indicates more room for idle circuit enrichment?
Interestingly, none of these bigger holes seem to effect my heavy throttle mixtures either, they are ~13.5-14.5.
