How does a Harley Twin Cam engine work?

The Twin Cam gets its name from the fact that it has two cams in the crankcase to activate the valves. At 88 cubic inches (1,450 cc) of displacement, it is the largest production Harley motorcycle engine, and it produces 80 horsepower. The engine remains air-cooled, and uses overhead valves activated by pushrods.

Why do Harleys sound the way they do?

Why do Harley-Davidson motorcycles sound this way? “The 45° design of the engine thus creates a plug firing sequencing as such: The first cylinder fires, the second (rear) cylinder fires 315° later, then there is a 405° gap until the first cylinder fires again, giving the engine its unique sound.”

Do Harleys fire both cylinders at once?

Yes both spark plugs fire at the same time but one cylinder is on its Combustion stroke while the other cylinder is on its exhaust stroke. Harley-Davidson considers the Rear cylinder the first cylinder to fire due to the rotation of the flywheels.

Do Harley-Davidson Pistons fire at the same time?

The difference in the Harley engine is that the crankshaft has only one pin, and both pistons connect to it. This design, combined with the V arrangement of the cylinders, means that the pistons cannot fire at even intervals.

Why do Harley Motors shake?

Harley-Davidson motorcycles, especially older models, vibrate because of their engine design. Pistons in Big Twin engines share a single crankpin causing the pistons to move in uneven intervals. In addition, the narrow 45-degree arrangement of the cylinders increases the tendency of Harley engines to vibrate.

Do All Harleys fire both spark plugs at the same time?

As others here have said already most Harleys fire both plugs at the same time. The rods are both connected to a single crank pin sandwiched between two flywheels. One rod is forked at the crank (female)and the other has a male end. They are pretty duarable considering the design.

Why do some bikes fire 45° apart?

There were a few experiments with flat trackers to make them fire 45° apart (called ‘twingles’) but all production bikes fire as above. It’s the cam and exhaust that makes them sound different for the most part. On edit: I forgot, it really is 1-2, but the rear cylinder is cylinder #1. At least that’s what HD puts in their training manuals.

How many degrees does a Harley Davidson engine fire?

This design, combined with the V arrangement of the cylinders, means that the pistons cannot fire at even intervals. Instead of one piston firing every 360 degrees, a Harley engine goes like this: A piston fires. The next piston fires at 315 degrees. There is a 405-degree gap. A piston fires.

Do all ignition plugs fire at the same time?

Modern Harleys with electronic ignition fire both plugs at the same time. It’s just that one cylinder is on it’s power stroke with a full intake charge, the other is not. A true firing order is only a factor if single fire ignition has been installed.