Due to some rule changes for the race season that is allowing the use of mikuni carbs I want to toss out the old keihin dual butterfly carb setup on my 1973 Yamaha gp433 and convert to a dual mikuni 34 mm setup. A couple questions I have are since the keihin bolt spacing is slightly smaller than the hr spacing can I modify the mikuni m-vm34-200k hr adapter to bolt up to intake or is there another adapter that will work. Another question I have is which vm carb to use. Get 2 vm34-389 snowmobile carbs or 2 standard vm carbs vm34-168/vm34-275 since I can get a right and left side carb. Last question would be any ideas on a base line jetting setup? Motor is stock with a stock exhaust. Any answers to this is greatly appreciated. Thanks chris