I am doing an evo buildup and wondered if anyone would weigh in on it. I was thinking I would run the SE-57 cam a 42mm mikuni with hi flow breather, 10.2:1 SE pistons, vance and hines short shots, SE gaskets and having my stock heads ported and polished. How much should I shave the heads? How high octane fuel will I need to run? What will my compression be? Thanks guys!

 

If you're going with 10.2:1 pistons already, how much more do you want to boost compression? Seems to me like that should be enough, short of a drag bike. At 10:1 already, you're going to need premium as it is. Unless you only want to run Av Gas.

 

Check out Bigboyzheads.com for your porting work. I probably wouldn't shave the heads. The rule of thumb is 11.1:1 is the cut off for pump gas. If you have the heads CC'd and tell the guy that does your heads, what compression ratio you're trying to achieve, he can CC and mill the heads to achieve that ratio. Because the pistons say they are 10.2:1 doesn't mean that's what the end result will be without the proper decking and the size of the compression chamber on the head. Also if you get the compression ratio to high you will need to install compression releases or a big starter. Also decide where you want the power to be,low to mid or wot. If are looking for more low and mid (the area that you use the most) you might want to look into a 2 into 1 system. Just my opinion. As far as the carb, I just bought a brand new Screaming Eagle Carb,which is a Mikuni Hsr 42, but the top cover is chrome and says Screaming Eagle off of ebay from Sun HD in Colorado for 209.99 shipped. It was the best deal that I found.