OEM Harley Shovelhead Rear Cylinder Jug 16587-66 – 3.48 in Bore / Approx. +.040

Genuine Harley-Davidson Shovelhead rear cylinder jug with casting number 16587-66. This cylinder measures approximately 3.48 inches at the bore and should be treated as a rebuildable machine-shop core.

Part Number / Markings: 16587-66
Condition: Used – machine-shop inspection recommended

USED PARTS DISCLAIMER: This is a used motorcycle part and may show normal signs of age, installation, removal, storage, and previous use including scratches, scuffs, discoloration, surface corrosion, paint loss, or other cosmetic wear. Any known damage or defects are noted when known. Unless otherwise stated, the photos show the actual item being sold and are considered part of the description.

BORE / IDENTIFICATION: Measured 3.48 in. Compared with the 3.4375 in stock 74ci bore, this is approximately +.040 in oversize.

FITMENT NOTES: The measured bore is consistent with a 74ci Shovelhead cylinder at roughly .040 over standard. Have the cylinder measured at multiple points in the ring travel before selecting pistons or rings.

FITMENT: Buyer is responsible for verifying fitment before purchasing. Fitment information is provided as a reference based on available part numbers, casting marks, measured dimensions, donor information, and published references. Motorcycles may have been modified over time. Compare the part number, casting, mounting points, bore, dimensions, electrical connections, and photos with the part currently on your motorcycle.

QUESTIONS? Send us a message before purchasing if you need additional measurements, photos, condition details, or clarification on what is included.

SHIPPING: Orders are typically processed and shipped within 1–2 business days after payment. Tracking is provided once the order ships. Parts are packed according to size, weight, and type. Large, heavy, or oversized items may require additional handling or shipping arrangements.