The Sommer 516 is a curiosity: a rattling diesel two-wheeler with 12 hp, but charming characteristics, as the driving report from our test editors shows. Production was discontinued in 2022.
- No longer manufactured, even used is hard to get
- Curious collector’s item, no electronics, top speed 105 km/h
- Consumption: Only about 2 liters/100 km
Table of Contents
Summer 516: Driving was an experience
The single cylinder thumps along. You can feel every single ignition of the crude-looking diesel engine. You might think that something like that has no place in a motorcycle. But you’d be wrong: after just a few kilometers of getting used to it, I’m finding the rattling motorcycling more and more enjoyable. Changing gears with your right foot takes some getting used to, as does the sound of the industrial engine, which usually does its job in a stationary and well-hidden manner.
Power 12 hp, top speed 105 km/h
Once you’ve come to terms with the unusual way of changing gears and the background noise, the Sommer Diesel 516 becomes more and more ingratiating. It carries its driver along bravely, chugging along, unobtrusively transferring its power to the rear wheel at low revs. This is pure driving. A disc brake at the front and a drum brake at the rear are all that’s needed to slow down the 165 kg machine, which can reach a maximum speed of 105 km/h.
27.5 Nm of torque at 2000 rpm – the Sommer develops its maximum thrust very early. Shifting is actually unnecessary . If you’re cruising along country roads at a leisurely pace (you wouldn’t want to do it any other way), you’ll do so in fourth gear, just as you would when driving through a town. And if you do shift back to third, you’ll be back in fourth at 2500 rpm.
The drive is called 1B50 and comes from the Hatz company in Ruhstorf an der Rott in Lower Bavaria. The inconspicuous steam hammer – originally developed for nautical and stationary purposes – has a lot to offer. Anyone who wants to understand the engine technically has to learn new vocabulary. This includes terms such as fan cooling (on the flywheel), plunger-type injection pump and double vortex combustion chamber or even alternating current alternator and tension spring regulator.
Durable and electronic-free
There are no nasty surprises when driving the Sommer Diesel. The chassis of the small-series motorcycle from Middle Franconia is clearly just right for the dynamics it can achieve. This also applies to long journeys, where the Sommer impresses with barely more than 2.0 l/100 km consumption and a good 600 km range. The ergonomics are good, and even after a long journey you feel comfortable on the rattling decelerator.
Since the engine was not Euro 5 compliant and the required ABS could not be implemented, production of the Sommer 516 was discontinued in 2022. And since they are real collector’s items, it is hard to get a used one.
Technical data Sommer 516
| Manufacturer’s components | Specification |
|---|---|
| Motor | Blower and air-cooled single-cylinder four-stroke diesel engine, two valves (operated by pushrods and rocker arms), displacement 516 cc, max. power 8.5 kW/12 hp at 3500 rpm, max. torque 27.5 Nm at 2000 rpm, dog-clutch four-speed gearbox (right-hand gearshift), toothed belt |
| chassis | Single-loop steel tube frame with closed beams, telescopic fork, rear swing arm with two spring struts |
| driving performance | top speed 105 km/h |
| brakes | Front single disc brake 280 mm with two-piston floating caliper, rear brake drum 152.4 mm, no ABS |
| Tires | Front 3.25-19, rear 3.50-19 |
| dimensions and weights | Wheelbase 1410 mm, tank capacity 13.5 liters, seat height 760 mm, empty weight 165 kg, permissible total weight 350 kg |
| consumption | combined 1.8 l/100 km, CO₂ emissions 47 g/km |
