i have 400ex and looking for more all around power !! i mostly ride and the dunes or on trails which would you recomend the sparks 416 or 440 kits??or other companyies that do good quality work?
i have heard the a 416 will beat a 440 is that true??
please help with these questions
thanks

 

go with the 416

 

Why do you rec 416 over 440?

 

Im also interested in how the 416 is better than a 440???? late,zubbeyboy

 

I'm no motorhead, but from what I've heard, the 416 is more reliable, and also revs faster, due to the lighter piston.

I am in the process of having a JE 10-8.1 piston, Hotcam Stage 2, and port and polish done.

I burnt my intake valves out, due to being too tight, so I figured while it's apart, why not.

 

seems like most, if not all of the top winning 400s have 440 and not 416. i think you need need to get some porting done to make the 440 shine.