Abstract: A motorcycle transmission (100) utilizes a shift fork (45), a shift collar (30) including a plurality of engagement teeth (30c) and a collar rib (30a) and a gear (34) (or one of the other six gears). The engagement teeth (30c) drive the teeth (34a) of the gear (34). A trap door (49), in combination with a threaded retainer (55), reduces axial play in shafts (37) and (75).

Abstract: An internal combustion engine includes a cylinder head and rocker box assembly that includes a duct arrangement that removes blow-by gases. In a first embodiment, a duct is formed from the upper surface of the cylinder head aligned with an opening in the bottom of the rocker box and proceeds to horizontal sections leading to a fitting with a line leading to an intake manifold. In a second embodiment, a single straight duct includes a straight angled portion extending downward at an oblique angle to the upper surface of the cylinder head to an intake port in the cylinder head. Action of the engine draws the unwanted gases from the rocker box through the opening of the ducts to an intake of the engine.

Abstract: An tuned induction system for use on a motorcycle having a V-twin engine. The tuned induction system having separate and individual first and second manifold bodies. Each of the separate intake manifold bodies having a flange that couples the individual manifold body to a cylinder head of the V-twin engine. The flange having a continuous radius that maximizes airflow velocity to enhance engine performance.

Abstract: An tuned induction system for use on a motorcycle having a V-twin engine. The tuned induction system having separate and individual first and second manifold bodies. Each of the separate intake manifold bodies having a flange that couples the individual manifold body to a cylinder head of the V-twin engine. The flange having a continuous radius that maximizes airflow velocity to enhance engine performance.

Abstract: An internal combustion engine includes pressure relief devices that reduce pressure due to compression during startup, thereby decreasing the force needed to start the engine. A pressure relief valve mounts on top of the cylinder head and includes a duct to the combustion chamber leading to the valve and a second duct leading to the exhaust port so that gases in the combustion chamber may be vented through the exhaust system. A mechanical actuator having cables directed to each of the pressure relief valves for each of the cylinders manually actuates a first embodiment. A second embodiment includes a solenoid with wiring tied into a starter circuit that actuates the multiple valves from a single actuator.

Abstract: An internal combustion engine includes pressure relief devices that reduce pressure due to compression during startup, thereby decreasing the force needed to start the engine. A pressure relief valve mounts on top of the cylinder head and includes a duct to the combustion chamber leading to the valve and a second duct leading to the exhaust port so that gases in the combustion chamber may be vented through the exhaust system. A mechanical actuator having cables directed to each of the pressure relief valves for each of the cylinders manually actuates a first embodiment. A second embodiment includes a solenoid with wiring tied into a starter circuit that actuates the multiple valves from a single actuator.

Abstract: A method of modifying the cam drive arrangement of a motorcycle engine. The method includes providing an existing cam gear arrangement having a crankshaft sprocket connected to a primary camshaft sprocket with a chain, removing the chain, replacing each of the sprockets with a crankshaft gear and primary camshaft gear respectively, and engaging teeth of the gears so the crankshaft gear drives the primary camshaft gear directly. A specific method for modifying a TWIN CAM 88 engine, made by Harley-Davidson, according to this method, is also described.

Abstract: A breather valve and arrangement for an internal combustion engine, having a scavenge hole that is open for a relatively long period of time relative to piston travel. Scavenge hole preferably subtends an angle of between 20° and 150°, and preferably is open from between 30° and 135° of piston travel. A method of replacing an existing breather valve with this novel breather valve is also described. Other arrangements for achieving the advantages of the novel breather valve are also described.

Abstract: An evaporative emissions control system for carburetors used in the internal combustion engines of vehicles, such as motorcycles, has an evaporative emissions control valve attached to the carburetor in the air intake path to the carburetor. The evaporative emissions control valve may be implemented as a sub-assembly add-on or as an integral part of a carburetor or back plate. The evaporative emissions control valve includes a valve, such as a rotatable plate valve, which may be electrically operated by an electrical actuator, such as a dual-wound solenoid actuator. At engine start-up, when the vehicle ignition switch and starter switch are both closed, both windings of the solenoid actuator are energized to provide a strong opening force for the evaporative emission control valve. During steady-state running of the engine, only a single solenoid winding is energized by the power provided through the ignition switch, to maintain the evaporative emissions control valve in the open position.