piston upgrade keeps killing my starter..

[Zzippp]

Thanks for all the info guys...
I really dont know alot about the busa's or anything about motor work on them. the guy i bought this from was big on racing so he told me "piston kit" lol im asuming biger pistons.. i do know that the bike has alot of compression from the info i gathered thats whats killing the starters.
please bare with me i went from a 600 SRAD to the hayabusa the only custom work i have had done is chrome and paint



here is a pic of the srad