User Tip: If you're unsure of your vehicle type, you may skip the machine type selection box.
Please select make, model and year
Big Bore KitsHigh quality off road big bore kits.

MIKE in TN
I purchased the Athena fit for my 2006 CRF250R. Wow....What a difference the kit made. Kit was very easy to install and is still going strong after 44 hours. If you want more power, this kits for you.
Read All Reviews
EMILY in IL
my husband locked up the motor on his quad and well needless to say a new engine is costly and a used one for the prices we could find wasnt very practical, he wanted to make sure he knew what was in his engine and what had been done to it, so we went the rebuilding road and this kit made things alot easier. We didnt have to find someone to bore out his motor wich where we live is kinda hard to do. so he got more power without cleaning out the bank account!
Read All Reviews
Mike in ID
I WAS A LITTLE SCEPTICAL ABOUT THIS PRODUCT. HOW COULD MOVING THE MOTOR 2.5mm MAKE THAT MUCH DIFFERENCE? AFTER READING SEVERAL REVIEWS ON LINE AND IN MAGAZINES I DECIDED TO GIVE IT A TRY. I COMBINED THIS PRODUCT WITH A MAXISS EN FRONT TIRE AND WOW WHAT A DIFFERENCE. I AM 250 lbs AND DIDN'T HAVE NEAR THE TROUBLE WITH THE "DARTING" THAT ALOT OF OTHER YZ OWNERS COMPLAIN ABOUT. THIS TOOK ME FROM REALLY LIKING MY BIKE TO LOVING IT. DON'T HESITATE. JUST BUY IT. INSTALL WAS FAIRLY EASY USING THE VIDEO ON THE DRD WEBSITE.
Read All Reviews