Big Bore 860 Kit / SD 850

Get ready to blow your competition away! We have abused our 860cc E-TEC motor package for multiple seasons now and it has proven to be a winner! This kit has all sorts of grunt and torque that just keeps on pulling!! In the steep and deep of the Rockies, to the flat lakes of Michigan, this is the motor that just keeps ripping. We all know the E-TEC is a heck of a motor, but with our porting and custom Wossner pistons the E-TEC becomes a real monster! It produces 180 horsepower and over 120 lb/ft of torque with our stage 2 porting on pump gas. Simply send us you stock cylinder, head and exhaust valves(Blades only please). We will then bore your cylinders, port them, modify your stock head, and machine your exhaust valves. For the best results go with our complete big bore kit which includes everything you need for the big bore motor package.

Kit Includes: Exchange Cylinders, Exchange Exhaust Valves, Exchange Head, Pistons, rings, circlips, and wrist pins.

 Recommended Options: Power Commander 5, Performance Manifold, Boyesen Rage Cages or V-Force Reeds, Stage 2 Clutch Kit, & Top End Gasket Kit. If you are running low altitude, you will also want to purchase our Big Bore Muffler.

 ***Unless purchasing outright –  you must send in cylinders, head, and exhaust valves (Blades Only)*** Package all contents VERY CAREFULLY and insure the package. BMP is not responsible for damages that occur in shipping. Core parts must be in good, usable condition. Parts not in useable condition will not be credited and the customer will be respnosible for return shipping.

Click here to download the general big bore instructions

Watch the video below for proper engine break-in protocol: