78 kz 650 4 into 2 carb size

Does any more feel that one 34mm mikuni flat slide is too small. I would love to know the math here. I feel there has to be a calcutiom that can be made. If one 42 can run a Turbo bike I feel this is with in the right range.. please tell me if I'm way off.

I used the calculation of the big cc Harleys run carbs in the 40"s so it must work on a 1200

with that said I wasnt entirely right. intake runner length and location affect the actual cfm IE High rise intakes on a v8 fortunately my runners were very long on the goldwing

I am sure there is a calculation when the built my Chevelle motor they did some kind of water test to figure out the overall volume and the calculation came our to 628 cfm carbuteyor and Holley just happen to have a 630 pro series available.

I am sure the calculation is the same look on the drag race forums

hope this helps

here is one that may help

www.csgnetwork.com/cfmcalc.html

I believe you want to match it to your max cfm (air flow) through the engine. Otherwise it will restrict the engine. This depends greatly on the rpm range of the engine which means that the 650 will likely run a much larger carb than a Harley of a similar size would. I think you'll be looking somewhere in the 38+ mm range to do it right.

disclaimer: I'm no expert.

Running and riding with a 38

Good job making it work. I've seen widely varying reports on how well these conversions work.

I'm considering doing a single or duals on a 4cyl Yamaha Venture 1200. I'm thinking a single 42 like ramtough did or a pair of 36s maybe?