I've got a build going with an older 3hp I/C that's in limbo, that's a newer one. Maybe 30 lbs with all the tins and tank on it a lot less without it. What were you wanting to know about it? Here is the thread, I started with another motor the Briggs stuff doesn't start until the 28th post on page 1. http://motorbicycling.com/showthread.php?t=44393
About weight, I have 60lbs rear wheel + 50lbs front wheel = total 110lbs. This a heavy build as I made a bunch of reinforcements that make it able to be used for trail riding. Alternately it is in the process of having an art cover that makes it resemble a fish to be used in parades.