Harley-Davidson Small Twin Flathead
Best known for powering the ubiquitous WWII WLA military bike, Harley's long-running '45' flathead is a popular collector's choice. It's prized for its classic pre-war looks and simple mechanics.
Harley-Davidson Small Twin Flathead sold for a median of $16,500 over the last 12 months, based on 11 auction sales; the middle 50% sold between $12,326 and $17,755. 12 currently for sale.
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22 listed in the past year. The last was 4 weeks ago.
Harley-Davidson Small Twin Flathead prices by year
| Year | Median (3 yrs) | Middle 50% | Sales (3 yrs) | For sale now |
|---|---|---|---|---|
| 1929 | – | – | 0 | 0 |
| 1941 | $21k | – | 3 | 0 |
| 1942 | $14k | $12k–$21k | 4 | 3 |
| 1947 | $14k | – | 2 | 0 |
Auction sales in the last 3 years; prices leave out salvage and other branded titles.
Harley-Davidson's small twin flathead, or "45," debuted in 1929 as the Model D. It was Harley's answer to the successful Indian Scout. The engine design evolved through the R-series and ultimately became the long-running W-series in 1937, with production for the three-wheeled Servi-Car continuing all the way to 1973. Its most famous application was the WLA, the ubiquitous military motorcycle of World War II.
These bikes are popular with collectors for their classic pre-war looks and mechanical simplicity. The 45 cubic inch flathead is a durable and reliable engine, and a huge parts supply exists thanks to its long production run and military service. WLAs are particularly sought after for their historical connection, but civilian models like the WL and the Servi-Car also have strong followings.
Buying Tips
- Check for matching engine case "belly numbers" and the VIN on the left engine case. Be wary of re-stamped numbers, which significantly impact value.
- Scrutinize the bike for originality. Many are built from mixed-year parts, so verify that the tanks, fenders, and accessories are correct for the model year.
- Listen for excessive top-end clatter or bottom-end rumbles. Rebuilding a 45 isn't complex, but sourcing good crankcases or cylinders can be costly.
- Confirm the title matches the engine number. Clean and correct paperwork is essential and saves major headaches later.
93 Harley-Davidson Small Twin Flathead vehicles have been tracked across auctions and listings on Hypercars, with 12 currently live.
Data sourced from auction results and dealer and private listings, including Bring a Trailer, Cars & Bids, Mecum, RM Sotheby’s and eBay Motors. Updated daily.
Frequently Asked Questions
How much does a Harley-Davidson Small Twin Flathead cost?
Over the last 12 months, Harley-Davidson Small Twin Flathead sold for a median of $16,500 across 11 auction sales tracked on Hypercars; the middle 50% sold between $12,326 and $17,755. There are 12 currently for sale.
How many Harley-Davidson Small Twin Flathead listings are for sale right now?
There are 12 Harley-Davidson Small Twin Flathead listings currently live across auctions, dealers, and marketplaces tracked by Hypercars.