Carburetor modifications and upgrades are second only to exhaust system upgrades when you get a new bike. Here are some inexpensive modifications, CV parts numbers for upgrades and tuning tips for all carburetors.

The ability of a new ignition system on an engine to produce additional horsepower is overrated. Does that ignition system really add horsepower? And what about single versus dual fire ignition? And don't forget about ignition coils and spark plug wires. If you were confused, a little information should help clear the air.

A performance camshaft is the order of the day when the desire for additional horsepower hits you after your Stage 1 tuning. You have just moved into Stage 2 engine territory. What is the correct camshaft to meet your need for speed and power? The Motorcycle Performance Guide provides some tips for picking   your camshaft and the most extensive list of camshaft specifications for Harley-Davidson engines available anywhere.

Cylinder head changes, porting and polishing are the buzz words when it comes to making high horsepower. What does a "good" set of heads look like? What does polishing really do for an engine? There are things that can be done to an engine that might give better results that big ports, giant intake valves and a fancy polishing job.

Want to know what engine modifications work? Here is an extensive group of mild to wild engine combinations producing horsepower to well over 150. A dyno sheet and a detailed list of the engine components are included with each description. From mild Stage 1 engines to wild Stage 4 engines, you'll find something of interest to you.

The drive train in your Harley-Davidson is an overlooked item. Overlooked until something fails. When your engine combination is above Stage 1, it is important that you have a heavy duty clutch and critical that you know how to adjust a belt drive.