Ironhead

The Ironhead Harley-Davidson engine was built between 1957 and 1985, and thus provided almost 3 decades of propulsion in the Sportster models. It is the successor of the K engines (from ’52), which still had to make do with 750 ccm and was later replaced by the Evolution (XL) engine. This gallery contains all Thunderbike conversions with Ironhead engines.

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