Well I am really sorry that I ruffled your feathers.....wait on second thought I am not. Ok I may agree with you that a aftermarket can will not hurt the motor, but here is where I differ with you, given that the motor is stock! I agree we can take a stock engine and swap out the stock can with just about any aftermarket can and we probably will not notice any difference in engine operating parameters, ie; exhaust temps, piston wash or plug color. Now you try to do this while running a RKT kit and you will get into trouble. You have a engine that has been changed dramatically in efficiency. You are dealing with different combustion chambers, different pistons which also affects port timing, leaner jettting, and a raised operating RPM. Is it any wonder that engines seize when you put on a aftermarket can after changing that many variables? Don't you think Kelsey tried to run aftermarket cans with his kits? Do you think it is possible that he noticed maybe a power loss or even piston failures when he tried aftermarket cans and that is why he recommends the stock can? I have heard of guys trying the Skinz can that Kelsey now recommends and even they noticed a change in plug color versus the stock can.
I know I tried to run a "thing "can with just his head on my 800 and he told me don't do it, you will have problems. Well two days later my sled was being pulled out of the backcountry because I stuck a piston. I installed his drop in kit at that point along with the stock can, that was three years ago and my sled still runs strong.
