The Mighty Honda MB5 “out in the wild”!

Jim Meyer spotted this clean little scoot and sent her in.

Steve, I spotted this today and had no idea what it was, never saw one before. Very cool little bike. Where has all the simplicity gone?

Good Question Jim.

These engines had decent specs including 185 psi compression! And I’ve read that some US versions had top speeds in excess of 50 mph. Wow!

Type Air cooled 2-stroke, reed valve
Cylinder arrangement Single cylinder 40 degree incline
Bore and Stroke 39.0 x 41.4 mm (1.54 x 1.63 in)
Displacement 49cc (2.98 cu in)
Compression ratio 7.6:1
Max Horsepower 7.0 BHP @ 9000 rpm
Max Torque 4.05 ft-lb (5.6 N-m)
Oil Capacity, transmission
Oil tank 1.1 US qt (1.0 liters)
1.2 US qt (1.1 liters)
Lubrication system Forced (eng) and wet sump (tranny)
Air Filtration Oiled polyurethane foam
Cylinder compression 185 psi (1275 kPa)
Engine weight 38.6 lb (17.5 kg)
Idle Speed 1400 rpm



  1. I remember these in the 80’s in the UK. It’s quite an amazing survivor, they were usually used and abused pretty rapidly. Regarding simplicity, I’m not sure a disc brake is required on a 50cc machine

  2. I took my MSF course on one of these. What a blast from the past! The MSF school I attended way back when was hosted at a school with a road circling the school. Every time we were out of the eyes of the instructor it turned into a flat track race. Great memories! Thanks for sharing this pristine example of a fun little scoot!

  3. I had one of these and I had a ball with it, even looped it once. The motor would rev to 10,000 but would take a long time to do so because of the heavy flywheel. I would rev it to 10K, pop the clutch and it would stand straight up and hold it there for a long time but once I tried shifting it into second and the heavy flywheel just pushed the bike way over vertical and I was left trying to run behind it at 15 mph which I did not do very well. I had so much fun when I was younger. Actually I still do.

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