yzf 426 motor or 450 motor or 400 motor

[pimpinyfz450]

i need a new motor for my cannondale hybrid right now i have a yzf 426 motor in it and i tried to do a valve job and when i was done i started it let it run as soon as i gave it gas it popped so now i am looking for a new motor or a complete top end what ever comes first .......looking to spend like 700

[matt250r21]

I will sell you my TC National 2002 YZ426 motor for $1500

[YTZ250#1]

I have a stock 400ex motor I will let go for $700

also have a good yz450 bottom end for $550. has a new billit clutch basket and a dirt digger clutch kit. motor ran good,but sold the top end.has minor crack in case near clutch rod & was fixed with an epoxy & does not leak.just looks a little crappy:D