Post Listing Update: this Thunderbolt did not meet reserve despite 16 bids up to $2,950 on eBay.
BSA is probably best known for the Lightning, but they also had a similarly-named touring complement known as the Thunderbolt.
Powered by the traditional 650cc air cooled twin with a single Amal carb, the BSA Thunderbolt (also known internally as the A65) had evolved to minimize vibrations found from previous BSA Twins. This allowed for sustained 70 mph travel in comfort for the first time. Plus, with a 4.2 gallon gas tank, riders were able to go over 200 miles per tank without filling up. The 46 horsepower engine enabled the bike to hit 104 miles per hour, and a dry weight of 385 pounds helped keep the bike manageable. Unfortunately, quality control issues in later models led to oil leaks and premature rust, tanking the reputation of this bike. This combined with the influx of Japanese bikes like the classic Honda CB750, contributed to the demise of the BSA Thunderbolt.
This example (VIN: A65TJG00919) has received some work in the last year, including a new fuel tank, petcocks, and a new Amal Super Concentric carb with internals suited for modern gas. It’s got electronic ignition and the seller rides it weekly. Find this Thunderbolt for sale in Bloomfield, New Mexico with bidding up to $2,650 and the reserve not yet met