131" KITS FOR 07-up TWIN CAM AND 99-06 TWIN CAM WITH SCREAMIN' EAGLE STROKER CRANK
Black Highlight 4.250" BORE CYLINDERS; 10.5:1 FLAT-TOP PISTONS
Requires use of big bore carb or throttle body.
If the Bolt-On Big Bore Kits are appealing, but just aren’t enough to satisfy your hunger for bigger, louder power then you will most certainly want to take a look at our Monster Big Bore Kits! These kits are ideal for the experienced rider who doesn’t mind giving the bottom end a complete overhaul in order to achieve the highest possible output from their motor! These kits utilize our larger 4 1/8” and 4 1/4” plated bore cylinders and as with all of our cylinders, these larger bores are also nickel-silicon carbide plated and all-aluminum pieces.
These kits allow for displacements as large as 107” and 114” cubic inches for 1999-06’ Twin Cam models using 4 1/8” and 4 1/4” cylinders, respectively. For the 2007–current models the displacement is carried up to 117” and a whopping 124” cubic inches of power! This is serious gain at an extreme level!
Of course, power of such magnitude doesn’t come without extra effort. Each of these Monster kits requires the cases to be bored wider to accept the new cylinders, as well as a crankshaft balance to even out the added weight that will be added to the bottom end. Of course, head flow services and larger camshafts are highly recommended to gain the absolute most out of these kits.