Make your old trusty Flathead mill run again as if shot from a cannon. These authentic reproductions of the 80 cui. cylinders Big Twin Flatheads of the 1937 thtru 48 year group. The engines of these bikes all feature the same 4-9/32” stroke, which means these 3-7/16” bore cylinders will hop up any 74 cui. mill (stock 1941 thru’ 48) to a full 80 cui. What a blast! Precisely made to the last detail with 11-fin design and stock-like markings for a period correct appearance.Manufactured from gray cast iron GJL 300 according to state-of-the-art foundry procedures. After all, metallurgy has made one or two advances since the 1930s, which improved stability and durability significantly. To ensure everything fits as it should the blanks are machined on CNC-equipment. All dimensions, gasket surfaces and threads are perfectly true to size. Another improvement are hardened and replaceable valve seats (unmachined) which allow safe operation with today’s unleaded fuels. Valve guides are not included in the scope of delivery and must be ordered separately.
Cylinders which are not offered as complete kits, i.e. with pistons and rings, are not finish honed. This job must be performed in a qualified workshop.
- fits Flathead Big Twin 1937-1948
- cast iron, cast finish
- length: 156 mm
- nominal bore: 3-7/16 ”
- inner Ø: 85.00 mm
- replaces OEM 16473-37, and 16474-37
Gaskets for Cylinder Base: 61 cui/1000 cc IOE 1924-1929, 74cui/1200 cc IOE, Knucklehead, Sidevalve Big Twin
Cannonball Big Twin Flathead Crankcases
All cases feature laser-engraved CB production numbers, which are registered and filed.
The selection includes cases with a smooth, uniform glass bead blasted finish and cases with an NOS (new old stock) finish. The latter means the finished cases are not bead-blasted but treated in a traditional process which gives them the appearance of new factory cases that had been sitting on the shelf for 50 years. Perfect for those "patina restorations".
Have any questions?
Our service team will be glad to help out: Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET, Phone: +49 / 931 250 61 16, eMail: email@example.com