Desmo Demystified

Ducati is considered by many to be the Ferrari of motorcycles. The comparison is well deserved. In addition to a long racing history, Ducatis are a joy to ride, expensive, beautiful and a pain in the ass to work on.

Let’s focus on that last one.

A simple desmodromic valvetrain in action.

Synonymous with the name Ducati is the term “Desmo,” short for desmodromic. A desmo valvetrain does not rely on springs to close the intake and exhaust valves. A cam lobe opens the valve, and another cam lobe closes the valve. This design has been used on almost all Ducati motorcycles since 1968.

While they did not invent it, Ducati are the only manufacturer to offer it to the public in significant numbers. The concept dates back to racing cars as early as 1914, but it was Ducati’s implementation on their 1956 125 Grand Prix racing bike that ushered in a new era. Back then it overcame the problems of stiff valve springs, metal fatigue or springs that weren’t able to close the valves quickly enough, a problem known as “valve float.” These problems the desmodromic valvetrain was designed to solve have pretty much been eliminated by modern metallurgy and more advanced valve actuation systems.

But I digress.

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Cure for Sticky Calipers

Or An Ode to the Lowly Grease Gun

My latest project involves an Italian motorcycle from the Seventies (yes, apparently I do have too much time on my hands). It’s a 1978 Moto Guzzi V50 that I bought in relatively good condition with 14k miles. It’s very complete and pretty much unmolested– meaning the fenders haven’t been buzzed off or removed. Of course, it’s still over 40 years old so… well, there are issues.

Moto Guzzi V50
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