Honda MB5

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The Honda MB5 is a 50cc, 5 speed motorcycle that was only imported into the US in 1982. It is, in fact, not a moped at all. However, it fits into moped culture due to its small displacement 2-stroke engine. Some features found on the MB5 were a speedometer, a tachometer (with a redline of 10,500 rpm), front disc brake, and Honda's Comstar wheels. The MB was the road oriented version of the Honda MT50.

Tech Specs

Overall Length 74 in (1880mm)
Overall Width 27.8 in (705 mm)
Overall Height 40.4 in (1025mm)
Wheelbase 47.8 in (1215 mm)
Seat Height 29.5 in (750 mm)
Foot Peg Height 12.2 in (310 mm)
Ground Clearance 6.3 in (160 mm)
Dry Weight 174 lb (79 kg)
Curb Weight 198 lb (90 kg)
Type Cross line backbone
Front Suspension,
Telescopic fork (dampenerod),
4.9 in (125 mm)
Rear Suspension,
Swingarm/twin shock absorber,
3.5 in (90mm)
Gross Vehicle Weight Rating 416.7 lb (189 kg)
Vehicle Capacity load 220.5 lb (100 kg)
Tire Size, front & rear 2.50 x 18
Tire Pressure, front
25 psi (175 kPa) front
32 psi (225 kPa) rear
Front brake, lining swept area Single disc brake, 59.6 sq in
(384 sq cm)
Rear brake, lining swept area Internal expanding shoe,
13.4 sq in (86.4 sq cm)
Fuel Capacity 2.4 US gal (9.0 liters)
Fuel reserve capacity 0.5 US gal (2.0 liters)
Caster angle 25 degrees
Trail 2.8 in (70mm)
Front Fork Oil Capacity 2.54 ozs (75 cc)
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
Carb Type PF 15, 16mm venturi bore
ID Number PF 15A
Air Screw initial setting 1 3/8 turns out
Float level 13.5 mm (0.53 in)
Main jet, standard #105
Main air jet, standard #210
Jet needle & position, standard 37B - 2nd groove
Slow/Pilot jet, standard #38
Drive Train
Clutch Wet, multi-plate
Transmission 5-speed constant-mesh
Primary reduction 4.117
Final reduction (sprockets) 3.307 (43/13)
Gear ratios, 1 to 5 3.083, 1.882, 1.400, 1.130, 0.960
Gear shift pattern left foot operated, 1-N-2-3-4-5

Ignition CDI (Capacitor Discharge Ignition)
Ignition timing "F" mark 19 +or- 3 degrees BTDC @ 3000 rpm
Full retard 10 +or- 5 degrees BTDC @ 7000 rpm
Starting system Primary kickstarter
Generator AC generator 66W @ 5000 rpm
Battery capacity 12V - 2.5 AH (YB2.5L-C)
Spark plug, standard
extended high speed riding
cold climate, below 5 C or 41 F
Spark plug gap 0.6-0.7 mm (0.024-0.028 in)
Fuse 7 Amp
Headlight (high/low beam) 31.5/30 W (sealed beam)
Tail/Stoplight 8/27W 3/32 cp (#1157)
Front turn signal 23W 32 cp (#1073)
Rear turn signal 23W 32 cp (#1073)
Speedometer light 3.4W 2 cp (#158)
Tachometer light 3.4W 2 cp (#158)
Neutral light 3.4W 2 cp (#158)
Turn signal indicator 3.4W 2 cp (#158)
High beam indicator 1.7W 1 cp (#53)

MB5 Threads

Some threads covering a lot of questions / issues people have had with mb5's

External Links

  • MB5 Supersite -- An awesome site for MB5 lovers. Lots of good technical information and advice.
  • MB5 Forums -- MB5 owners forum.
  • MB5 parts list -- This site has really useful exploded diagrams so you know where everything goes.
  • Honda Manuals -- more MB5 wiring diagrams, parts and owner's manual downloads
  • MB5 Shop Manual -- 90MB, high resolution, good quality
  • MB5 commercial -- Honda MB5 commercial from back in the day.
  • Honda MB5 Owners -- Honda MB5 Owners (FB login required), small community of MB5 owners across the world.