I'm working with a DOHC motorcycle engine, where I can adjust the lobe centers per cam, and am trying to get the best of all worlds.....best power for the boost, and good off boost performance.

Now here is where I get frustrated. People talk a lot about lobe centers, but then lobe centers can change drastically by what amount of duration the cams in question have. It seems to me like there is a certain "realistic" intake opening and exhaust closing (overlap) and as long as the intake closing and exhaust opening stays within reasonable range, and adjust from there as necessary to keep it balanced.

I attempted 106/109, which was recommended from others, but have been having problems with the engine at higher RPM's...and then started calculating what it would do to the overlap, and discovered that I have NEGATIVE overlap, which I figure can't be good. So I thought I'd try 100/109 and see what happens, but I'd really like to hear some good generic numbers and rules to go by....or links to good basic's explained.

Thanks.