This is what Motor Cycle Mechanics
(May 1980) had to say about the "new" Honda
MB5. Tasty MB50......
The new honda MB50 looks good, sounds good
and smells good - in fact, it's pretty tasty!
With its limited 30mph performance any six teener
special will have to appeal to the senses if
it is going to sell; and the MB50 does.
Looking more like a road racer than a 30mph
"slowped", the little Honda shouts performance
from ever viewpoint. the clip-on type bars ,
the small flyscreen and the cast alloy wheels
all suggest this bike can move, what a pity
it's all a sham.
Don't get the wrong idea, riding the MB50 in
London traffic is just as exciting as riding
any other 30mph restricted machine - in place
of "exciting" you could read dangerous!
isn't enough power to keep up with the majority
of the traffic which flows nearer to 40mph than
30. Honda have certainly done a good job while
working within the limitations of 30mph restriction
law. You do get an impression of speed, but
that's all you get.
If the Honda express can manage its 30mph performance
with only one gear how come the MB50 needs five?
It's all part of honda's deception. First gear
is very low. In fact, flat out are going little
faster than walking pace _ but the take off
is teriffic. Even with a modest amount of throttle
you can lift the front wheel by dropping the
clutch although it's not recommended to help
transmission life! The tacho doesn't exactly
whizz around the dial but you can use it to
change up at peak revs.
Once you reach third gear, I found it just
as quick to prod the pedal straight into top,
rather than wring the motor out in fourth. Top
speed indicated indicated was 35mph which is
about right allowing for speedo error and the
govenment's percentage leeway.
honda make a point of stressing the MB50's
low centre of gravity and three-spoke Comstar
wheels. we can't say how much this contributes
to the handling but we can say that the bike
handles quite well _ for a moped.
The disc brake is certainly more than a match
for the performance and it is pretty easy to
lose more speed than you intended because of
it's deceptive power and light action. The chassis
could cope with a lot more performance but Honda
claim it isn't posible to tune the engine.
Basically, the power unit is a single cylinder
two-stroke with reed valves controlling the
intake. The inlet port has a similar bore to
the fuel tap on the CB900F and an equally restrictive
exhaust port. What is interesting is that Honda
have seen fit to design the motor with a "balancer"
It's difficult to believe any two-stroke this
small needs such a device to damp out vibrations
and it may just be a way of increacing the flywheel
mass without building a large crankcase to house
it. the motor also features electronic ignition
with its own built-in advance system.
The combustion chamber is a new design and
this, Honda claim, allows the engine to run
at low town, speeds without fouling the plug.
The massive finning on the engine is also said
to aid low-speed cooling. Since the engine produces
just about zero power, and therefore heat, we
would think that the cooling fin size is designed
for looks rather than efficency.
As for the low speed, clean running, combustion
chamber I can't see anyone riding this bike
at anything other than at flat-out pace!
In the UK the MB5 was available
in three colours. Black was the most popular
chioce, followed by red. White was a poor selling
colour and as a result it is now a rare
bike. In mainland Europe blue was also offered.
Engine Data: (Restricted
- Type: Air Cooled, Single Cylinder, 2 Stroke
- Bore & Stoke: 39mm x 41.4mm
- Displacement: 49cc
- Compression Ratio: 6.4:1
- Lubrication System: Honda 2 stroke oil injection
- Oil capacity:
- Transmission 1.76 pints
- Engine 1.94 pints
- Starting System: Primary Kick
- Maximum horsepower: 2.55 PS / 6000 rpm (DIN)
- Maximum Torque: 0.41 kg-m / 4500
- Type: Cross Line Backbone Design
- Front Suspension: Telescopic (travel 4.9inch)
- Rear Suspension: Swing Arm 3.5 inch
- Front Tyre: 2.50 x 18 - 4PR
- Rear Tyre 2.50 x 18 - 6PR
- Front Brake: Disc
- Rear Brake: Internal Expanding Shoe
- Trail Lengh: 2.8 inch
- Caster Angle: 65 Degrees
- Type: 5-speed Constant mesh
- Clutch: Wet multi-plate
- Primary reduction: 4.117
- Gear Ratios 1st: 3.083
- 2nd: 1.882
- 3rd: 1.400
- 4th: 1.130
- 5th: 0.960
- Final reduction: 3.750
- Drive Sprocket: 12T
- Driven Sprocket 45T
- Ignition: Fully Transistorised
- Alternator: 0.049kw/5000rpm
- Battery Capacity: 6V-4AH
- Headlight low/high: 25/25 watt
- Tail/Stoplight: 5/21 watt
- Indicator Light: 18watt
- Overall length: 74.0in
- Overall Width: 25.8in
- Overall Height: 45.7in
- Wheelbase: 48.2in
- Seat Height: 29.5in
- Ground clearance: 6.3in
- Fuel capacity inc. reserve: 2.42 imp gals
- Dry Weight: 179lb
- Curb Weight: 198lb