I know rod to stroke ratio is bad as it is infinitly said on here... But i was wondering if anyone had an idea as to what the "weakest" part of the F is. Its broad i know, but im just wondering what the major limiting factor to higher revs is? valvetrain? crank? rods..?? My guess is valvetrain but i wanna here from someone who has dealt with building these engines or has an experience as to what breaks when turning these things... This being stock of course.. ha im not interested in how ur eagle rods broke. Im more interested in what has to go that is stock

 

i am not familiar with f22bs, but f22s were never designed to be a high revving engine, more of a low end torque producer. most f22s fall on their face above 5500 rpm anyhow, so why not focus on your engines strengths instead of trying to build a 2.2 liter b16?

bisimoto has a forum, i think you might find some good info on there as well.

 

you're right, the R/S ratio is less than ideal.. another thing to consider if you plan to rev past the stock limit is upgraded valve springs, spring retainers and maybe stainless (lighter) valves.

the two things you're trying to avoid are dropping or floating a valve and tossing the rod through the side of the block.

a motor is more than it's internals, so just because most F22s fall on their face above 5500 doesn't mean the right cam, manifolds and tune can't push that much higher.

you can compare the specs of the motor your looking at to specs of any range of other four-stroke with differing power band and rev limit. you should be able to glean a good bit of info from that.