Bolt On Power For Your Twin Cam Harley Davidson

 by: John Gall

For those owners of the Twin Cam Harley Davidson Motorcycle you may find that the 63 HP your bike has from the factory is not quite enough power. While the Twin Cam engine is a great improvement over the 80 inch Evolution motor there is much that can be done to make more power.

Stage 1
The Twin Cam motor in most new Harley Davidson Motorcycles is stock as an 88 inch twin cylinder motor. Stock horsepower is around 63 and makes for a decent ride with generally acceptable power. Adding what is known as a Stage 1 kit can boost this power to 70+ HP. A typical stage 1 bolt on will include new exhaust, and air cleaner. Some folks will also put a carb kit in their stock CV carburetor or bolt on an aftermarket carb like an S&S B or Mikuni HSR42. For those folks with fuel injection a new map can be added that will make your motorcycle work well with the new exhaust and air cleaner.

Stage 2
When 70HP isn't enough, you can get to about 80 HP by adding a big bore kit. You can either have the cylinders bored out or bolt on new cylinders. Harley sells a 95 inch big bore kit that includes the new cylinders and pistons. I'd recommend using Forged pistons as they can be reused if you decide to add new heads in the Stage 3. Common in the stage 2 build is the addition of a new CAM. The combination of the 95 inch kit, cam and pistons should get your motorcycle in the 80HP range.

Stage 3
For those with more money to spend you can further boost your power 90-95HP by adding new Cylinder Heads and forged pistons. On my 2000 FXSTS this put me at 96HP and 100 Ft/Lbs of Torque.  Depending on the parts you choose you may get more or less HP than what's indicated here. The idea was to provide a basic description of the various stages and parts involved.  For exhaust I’d recommend for max midrange benefit choose a two into one system. If you must go with a two into two then try and find a manufacturer that specializes in performance like the Python III. There are many makers of great looking and sounding pipes but performance is usually an afterthought.