Carlini Torque Arm
We know what you are thinking. What on earth is a torque arm? A good question with an easy answer. A torque arm is an aluminum brace that installs between the engine and transmission of Harley-Davidson Evolution Big Twins.
Okay, so why would you want one? Well, that one doesn't have such a easy answer. Let us start with some background information first.
background
Today's Harley riders have more horsepower at their disposal than ever before. Hopped-up Evo mills routinely register near triple digit horsepower. This is a good thing. However, the Motor Company does not design its motorcycles to handle twice their stock power output. This design "weakness" usually shows up first in the connection between transmission and engine. The transmission of a big twin Harley is connected to the engine at only two points: the central mounting bosses between them, and
In some cases this configuration can lead to an unbalanced loading of forces. Engine transfer of power to the left side of the transmission causes this imbalance. As such, the primary chain is in effect trying to pull the left side of the transmission towards the engine. Normally, the transmission mounting bolts are sufficient to contain this torque load. However, this configuration was not designed to handle increased torque generated by a real asphalt ripper.
how does it work?
What a torque arm does is "unitize" the engine and transmission. The torque arm connects an Evo's transmission to the right side of its engine. If you've been following along you will no doubt remember that the inner primary case connects the transmission to the left side of an Evo engine. Now the transmission is not only connected by mounting bosses in the center and the inner primary case on the left, but also by the torque arm on the right. This setup makes all the components happy. And there are no unbalanced loads lurking around to cause failures.This arm was designed by Tony Carlini of Carlini Design. Carlini originally developed the torque arm for his high-powered "Black Bart" custom Dyna Glide. He had grown tired of replacing primary cases on it. Imagine that.
With the pipes off and the transmission door open, installation of the torque arm was just a matter of removing and replacing six bolts. Three bolts are removed from the transmission and three bolts from beneath the nose cone. The arm slides right into place and is installed with six replacement bolts. Re-install the transmission cover and exhaust pipes and you're good to go.
performance
The change in ride performance is immediately noticeable -- albeit a little hard to quantify. You find yourself describing how the bike felt without the torque arm in terms you would have never used before installing the arm. For example, power transmission is no longer "spongy." The bike no longer "porpoises" during quick bursts of acceleration. Handling is definitely improved. Corners are now something you throw the bike into. You feel more in control. As mentioned, the change is hard to quantify. Suffice it to say, while the ride was never bad before, it is definitely better now. As required by current aftermarket standards, the Carlini torque arm is fabricated from billet aluminum
If you're happy with the stock performance of your sled, pass this by. Its benefits will not be noticed as much as the hole in your wallet. However, if you bought that scooter to build and ride, the Carlini torque arm should definitely be on your list.
Motorcycle Online Rating: ****The arms are available for all Harley-Davidson Evolution big twins: FXRs, Dynas, Softails and Electra Glides.
where to get info
Carlini DesignHighway Art Corporation17516 Von Karmen AvenueIrvine, CA 92714(800) 398-0222
More by Don Crafts, Chicago Desk
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