i hate CV carbs. due to the way they operate they are not directly comparable to other styles of carbs. i plan on using something similar to a crf450 carb (FCR40mm) when i do my engine build on the ascot. or maybe one of the edelbrocks, they are slightly larger, and would provide a tad more top end.
no unless you have MAD port work and a perfectly tuned exhaust, i just do not think the ascot (with even a mild overbore) could move enough air to outflow a 40mm FCR. i would almost bet money that the crf450 carb in stock form would be jetted close if not larger then what it would need to be used on an ascot motor. while 500cc is a fairly good sized single, it just does not take that big of a gulp on intake.