Motorcycles are kinda the last bastion of manual transmissions. The obvious difference between automatic and manual transmissions is the clutch. Wait, scratch that, automatics use clutches of a sort too, so it's really more about the fact that the majority of motorcycles use a clutch operated by hand, instead of a computer or series of hydraulic valves. The hand clutch (as we know it) is a unique contraption, mostly because of it's operation and it's operator, you. Humans are a trifle more erratic in their clutching techniques than any automated system could ever be, which plays into the details of design in good motorcycle clutches. Inconsistent engagement and release and the nature of friction in a "wet" clutch design (especially in big V-twins making prodigious torque at relatively low engine speeds) can lead to a whole host of issues in the pursuit of the perfect Harley-Davidson clutch.
We are very aware of the imperfections and the issues that can arise such as clutch slip, or crappy engagement, and "hanging" on quick shifts. But the real killer is when something comes apart just when you need it most. The thing is, the bulk of these issues we bring on ourselves. Aside from sheer abuse, there are two things common to most clutch woes. First is our propensity to hop up our engines. Seems clear that when you make a lot more power you push the capabilities of the clutch right to the edge, and often beyond. Second, most of us don't have a clue what those capabilities are in the first place. Lucky for us, there's a company out there that understands all of this, Barnett Tool and Engineering. And they have been making effective solutions to the problems we've just discussed since the late fifties. Even though Barnett is well-known for its control cables, it's the high-performance clutch components that are a point of pride with the company. Not without reason, since they have really outdone themselves with the Scorpion basket and clutch kit for 2007 and later (six-speed) Big Twins.