I showed a photograph of this vintage BMW hot rod last week before we left for Baja, and when I returned to the plant this morning Gerry had it pushed out front. It was an opportunity to grab a few more photos and I did…
The bike is cool. It’s a 1962 R50, which was originally a 500cc BMW boxer twin. The “boxer” nomenclature refers to the engine configuration. The pistons move back and forth horizontally (like a boxer throwing punches), with one cylinder sticking out on either side of the bike.
The boxer in those days was an overhead valve engine, which means the valves were above the cylinder and they were actuated through pushrods, which were in turn driven by a cam lower in the engine. The chrome tubes you see above the cylinder in the photo above house the pushrods.
Pushrod engines are definitely old school, and the pushrod overhead valve engine design has been around for at least 60 years. It still works well, though, and it generally makes an engine easier to maintain. Our TT250 is an overhead valve pushrod engine, and I am more than pleased with the performance of mine. It’s a little torque monster. On the recent Baja trip, I found I could pretty much leave the TT250 in 5th gear once I hit 30 mph. I rode through most of the mountains without ever downshifting.
BMW made both a 500cc and a 600cc model back then (I’m pretty sure the bikes were the same, other than engine displacement). They also offered a high-performance version of the 600cc engine and that model was designated as the R69S. This bike has the R69S engine and, of course, a sidecar. Sidecars are cool. They’re not my cup of tea, but that’s okay. Some folks love them. Our good buddy Dan has two Urals (a contemporary Russian motorcycle based on the BMW boxer twin design) with sidecars. Oh, one other thing I almost forgot…BMW also offered a smaller single-cylinder bike back then. The size? It was a 250, of course…the ideal size for real-world adventure travel. It was based on just one of the BMW’s cylinders, with the piston traveling straight up and down (much like the TT250).
Another oddity that distinguished the BMWs of an earlier era were the Earles forks. Instead of using a telescopic fork design, BMW used the Earles concept, which is sort of a reversed swingarm for the front wheel…
The Earles design, I’ve read, works better on a bike with a sidecar.
I’m a vintage bike fan, and I always have been. I’d love to own one of those early BMWs like you see in the photos above. They’re just cool. Tomorrow I’m headed to the Doffo vineyards here in southern California, where the owner has a large collection of vintage bikes. It’s for a story I’m doing for one of the motorcycle magazines. Watch for photos here on the CSC blog.
Speaking of classic bikes, my money is on the RX3 as a future classic. The bike’s design is iconic, and it certainly is making waves in the motorcycle world. We’ll see.
SG250 San Gabriel Cafe Racer
TT250 Enduro