Tune Up a BMW /5 Airhead Engine

Reader Contribution by The Motorcycle Classics Staff
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Last time, we showed you how to adjust the valves on a BMW /5 airhead twin. Valve adjustment is the first step in a comprehensive tune up, followed by replacing the ignition points, spark plugs, air filter, and setting timing. While replacing ignition points and setting ignition timing can be a laborious process on some bikes — Kawasaki triples spring to mind — it’s extremely straight-forward on BMW’s /5 twins.

A few points are worth noting. First, never remove the front engine cover without first disconnecting the battery. On /5 airhead BMWs, the alternator is located directly behind the front cover; if the battery’s connected you can potentially short the alternator by grounding it with the aluminum cover.

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