Big Bore

To "stroke" an engine, the crank pin(where the lower end of the rod attaches) is moved towards the outside of the crank weights, so that as the crank rotates, the piston moves farther up and down in the cylinder, thus increasing displacement. Usually, this requires a longer cylinder to accomodate the increased travel of the piston upward, but in the case of the Wiseco kit, this step was eliminated by fabricating a piston with the wrist pin located farther up in the piston( the exact amount of increased stroke) therefore simplifying the process. Power increases should be substantial, not only because of the increased displacement, but because of the mechanical leverage advantage the stroke angle provides. In high RPM motors, piston speed becomes excessive, but in an engine like the triumph, that is not a concern. However, if all you are interested in is horsepower, and not the type of bike it is delivered in, you are better off changing to almost any other bike, as they are all more powerful than our triumph twins.