518019 Pinion shaft, 39-53 B.T.

This MCS pinion shaft is a high-quality replacement component for the internal timing assembly of early Harley-Davidson engines. It is designed to fit 1939 to 1953 Big Twin models, serving as a direct alternative to the original equipment part number 24006-39. Proper pinion shaft alignment is critical for the longevity of your oil pump drive and cam gears, and this shaft is machined to provide the exact fitment required for these vintage machines. It is an essential part for any mechanic performing a bottom-end overhaul on a Panhead or Knucklehead from this era, ensuring smooth operation and factory-spec performance.