480 big bore athena

[wckedclownz69]

so im getting an athena big bore and im getting a hotcam stage 2.... i have on 05 450r and was wondering should i replace the crank bearrings just to be safe or do u think just slap it on... wht sixe piston does the big bore come with too... and wht kind of gas would i have to run with it....anyone kno the best sprocket sixe to run with it for the best power for mx...

[bloodmoney23]

keep the same sprocket, bike is basically designed for mx out fo factory. not sure what piston it comes with you shoulda checked when you ordered. I know 13:1 compression you have to run race fuel and you can run race on a 12.5:1 as well but not needed. If you have quite a few hours on bike then replace the bearings on crank. They should be good but its going to be a lot of strain on the crank. But like i said they SHOULD be good so you dont HAVE to. check when you rip it apart if there is any play in it at all.