Kit Includes

Fat Boy 4 Complete Exhaust System, JE forged piston kit (12-1), Cylinder Sleeve, Bore and ReNikasil, Stroker Crank with Forged Knife Rod, Head gasket, Camshaft (see grind options below), Big Valves +1.0mm S/S IN & EX, HD Valve Springs w/Titanium Retainers, Shortened Bronze Guides, DR Head Porting and Serdi Valve Seat Machining, K&N Air Filter Instructions, DR Tech Support.

Call for displacement options and additional information.
*This kit requires NO cylinder base plate or cam chain modification
Center case machining may be required to clearance connecting rod on stroker crankshaft (an additional charge will apply) call DRI for details

Kit Options

Camshafts
Motocross Cam
X11 Grind "Midrange/Top End" Power Gain (Lift .430"/.385" Duration 266°/282°)
Baja/Cross Country Cam
X22 Grind "Bottom/Midrange" Power Gain (Lift .412"/.350" Duration 260°/268°)
TT/Drag Race Cam
X33 Grind "Maximum Top End" Power Gain (Lift .435”/.385" Duration 276°)
Power Gain: 20 + HP

Compression (525cc)
12-1 (Race Gas)

Valves
OPTIONAL: +1mm or +2mm Titanium Intake Valves available, add $200.00 to kit price for 1 pair.( $399.00 per pair if sold separately)
OPTIONAL: + 2.0mm Stainless Steel Intake and Exhaust Valves Call for price and install options

Carburetor and Ignition
CRF 40.mm Carburetor
Vortex X10 CDI

Cores
Kit Price is plus any OEM parts.
*Customer Cores Required: (Must send in to DRI) Cylinder, Head and Crankshaft for modification.(or purchase new cores, DRI keeps in stock, see below)
*Customer may purchase from DRI new cylinder, head and valve cotters for $595.00..
*Customer my purchase, from DRI, a new crankshaft $310.00
*If cores are purchased new from DRI, customer will not be required to send their parts to DRI.
*DRI will ship new modified and assembled head along with freshly bored and re-plated cylinder.
*If new core route is taken, customer will be responsible for setting valve lash.
*Machine Work: Center case machining required for connecting rod clearance ($150.00).
Machining price plus teardown and reassembly.

Delivery Schedule
Average lead time for Big Bore National kits is 6 weeks.
Duncan Racing Complete ('06-'07) 525cc Engine Performance Package for the Honda TRX 450R