Thursday, 24 June 2021

Honda MTX80 S, R, R2

"Closely following the lines of its bigger brother and the winning lines of Honda's outstanding works Motocross machines, the MTX80 adds an exciting style to your riding. Its 12ps liquid cooled engine is a match for many 125's and is backed by a full size frame 21" front wheel, engine balancer for minimal vibration and Honda's renowned Pro Link suspension."

The MTX80S HD06 was Honda's second gen off-road styled lightweight and an evolution of the MT8. The first generation MTX80S used the same longer stroke air-cooled motor first found in the MB8 and MT8 but had an updated cradle style chassis featuring a pro-link rear suspension and a more conventional fuel tank.


The Second generation MTX80R HD08 model was completely revised to bring it in line with its road going stablemate to the high-tech MBX80. It featured the shorter stroke, higher revving liquid cooled 79cc motor producing a heady 12ps and weighing just 89.5kg it ensured great performance. Styling was based on the Honda CR motocross bikes of the era. Versions include round or square front headlights and pillion foot pegs either on a subframe loop or mounted to the swing arm.

MTX80RF with square headlight
MTX80RS with round headlight

The third generation bike the MTX80R2 HD09 was based on the larger MTX125 chassis using the engine from the pervious HD08 machine. Improvements other than size came in the form of larger/ stiffer forks and a 240mm front disc brake. Again power was claimed at a full 12ps at 8000rpm which was the maximum power a learner bike could have in the UK anyway but with the bonus of cheaper insurance premiums of the 79cc engine.


Model years 

1982-86 MTX80S HD06

1983-86 MTX80R HD08

1986-89 MTX80R 2 HD09




Engine type

Air Cooled 

Liquid Cooled

Liquid Cooled

Engine size




Max power


12ps, 8000rpm

12ps, 8000rpm


6 speed

6 speed

6 speed





Seat Height








Fuel Capacity

9 litres

8 litres

9 litres

Front Wheel

2.50 21

2.50 21

2.50 21

Rear Wheel

315 18

3.25 18

3.25 18

Front Break




Rear Break




Rear suspension

Pro Link

Pro Link

Pro Link

Friday, 5 June 2020

The M family

I have been attempting to produce a family tree for all the Honda M models. The models can be grouped into to distinct series, the first are all models with the same basic engine architecture which includes all models sub 100cc (including H100) and secondly all models that are directly related by model series but not connected with engine architecture which is all models 125cc and over.

50cc, MB5, MT5, MM50, MTX50, MBX50, MCX50, TLM50, RTL50, MTX50R, NS50, NSR50, NS-1, NSR50 (mini), CRM50

75cc, MBX75, NSR75

80cc, MB80, MT80, MBX80, MTX80, MCX80, NSR80 (mini), CRM80

100cc +, H100 (MB100), MBX125, MTX125, MTX200, MVX250

Wednesday, 5 February 2020

Honda NS50F, NSR75 and NS1

The NS50 and NS-1 models have the final evolution of the M engine architecture that dates back to the MB5. The NS50F was also sold in some markets as a NSR50, but both are designated as an AC08 model, but with a full fairing and 'of the era' paint schemes. There are is also a full size model variant of the NSR50R (with duel seat and conventional fuel tank, model AC14), not to be confused with the NSR 50/80 Gag bikes.

1987 NS50F

The NS50F / AC08 was introduced as the successor to the previous MBX models and used styling inspired by the CBR 'Aero' models of the era. The NS50F borrows heavily from the MBX not only with the engine but also with the modded chassis to accept new bodywork and a fuel tank that is modded to take the half fairing. Equipped with 17-inch front and rear aluminium cast wheels, a seat cowl with a built-in glove compartment, and bright halogen headlights.

Type 1

1998-90 NS50F 

In 1988, the engine was updated with a new airbox and exhaust to improve usability at medium to low speeds. The following year, in 1989, it gained a dual headlight set up with a more heavily drilled front disc rotor.

Type 2

NS50F Special Edition 1988
AC08 NSR50 version with full fairing and Tiger 2 paint scheme

NSR75 Spanish Market version

The NS50F was also produced in Honda's Montessa factory with a 75cc engine to meet the Spanish licencing laws and confusingly also called it an NSR, this replaced the MBX75.

1990 NS50F (wire wheels)
For the 1990 model year a stripped down version of NS50F was available with some funky (of the era, think Aprilia!) graphics and featured wire wheels and drum brakes. What was interesting is that this bike was sold with optional extras, which included the handlebar fairing, radiator cover and belly pan from the MBX

NS50F fitted with the optional extras


HRC launched the NS50R in 1996 when production of the NS50F road bike ended, it featured the familiar single cylinder liquid cooled engine producing 7.2hp at 10,000rpm but running pre-mix fuelling. Other features included alloy rear sets, single seat, 3 spoke wheels and stripped of the road running gear it came in at just 75kg and sold for Y198,000.

1991-94 NS-1

The 1991 NS-1 / AC12 type that appeared as a successor to the NS50F and sold together with the ‘Gag bike’ style NSR50 / 80. 

The NS-1was a full-size sports model styled like a small MC21 NSR250 featuring a 17-inch wheels, single seat unit, full fairing and produced a healthy 7.2hp at 10,000rpm from its single cylinder liquid cooled engine. The NS-1 features an all new pressed steel chassis designed to mimic the alloy chassis's of more expensive bikes, again the engine is an evolution of the MB/X design.

A cool feature of NS-1 was it’s ‘Met-in’space situated where the fuel tank traditionally lived that opens up and is large enough for a full-face helmet with the fuel tank under the seat. Also available were lots of official accessories that even included a rack that fitted on top of the rear seat hump!

Met In

1995-96 NS-1

In 1995 the model was updated with the addition of the RVF style twin headlights and improved electrical system.In 1997 the model featured a blacked out frame and wheels. The NS-1 was very popular despite the fact that it was very expensive, about 300,000 yen.

1995 With twin headlights

1997 NS-1

Colours, solid red, solid silver and HRC
1997 Twin headlights and black chassis

NS-1 - MH80R

As an interesting footnote Moriwaki Engineering, a Honda-based tuning and manufacturing company, sold a racer machine called the "MH80R" which used the NS-1 as a base and fitted the CR80MX engine. The MH80R was used in a one-make race series not only in Japan but also overseas. Check it out on their website here


Friday, 22 November 2019

Honda MT50

The Honda MT5 or MT50 was the sister machine to the MB5 but with revised off road styling but still shared many of the MB's features like  the air cooled single cylinder engine with the ballancer shaft in a visually similar steel back bone frame but with longer travel suspension, wire wheels and knobbly tyres the MT5 looked ready for the dirt. Like all Honda's it was heavily restricted and was rather unfairly criticised for being slow against the competition of the time, but keep in mid the legal limit was just 30mph! European models fared better and were much faster, there was also a pedal version (like the MB5) sold for the Dutch market.

Originally introduced in 1979 and was initially replaced in 1982 with the MTX50 the MT was re-introduced in 1985 and ran all the way to the model year 1996 for some of the Scandinavian countries.

Because of the length of production and popularity of the model spare parts are plentiful making it a prime model for restoration.

What Honda said:

"With Honda's MT50S Sports Moped, 16 year old's can enjoy all the performance that comes from Honda's experience from thier race winning Motocross world team.
Looking just like a smaller version of the World Champion Dave Thorpe's bike, Honda MT50S is a true motocross styled machine, yet it's entirely street legal for 16 year old's.
The MT50S has a 49cc air-cooled 2-stroke engine that is fitted with a balancer to help minimise vibration levels. Maintenance is kept remarkably simple thanks to the ultra reliable Capacitor Discharge Ignition. And to eliminate an automatic oil injection system. A close ratio, 5-speed transmission means that you can always be in the right gear at the right time.
To keep you ahead round the corners or when the going gets rough, the MT50S has hydraulic front forks with a full 135mm of travel with twin hydraulic dampers on the rear giving 125mm of axle travel. Plenty of safe stopping power is provided by the leading/ trailing drum brakes fitted front and rear.
To complete the exciting specifications of ths motocross styled machine, the MT50S has fitted indicators, twin rear view mirrors, a rectangular headlamp with cowl and some striking new colours and graphics for 1986.
Following in the tracks of Honda's successful motocross bikes, the MT50S also has a competitive price to complement its competitive performance."

Honda MT5 S-G Specifications
Engine – Air cooled, single cylinder, 2-stroke, reed valve induction
Capacity – 49cc
Bore x stroke – 39 x 41.4mm
Compression Ratio – 7.4:1
Carburetion – 13mm Keihin PF05B
Max Power – 2.55bhp @ 6500rpm
Torque – 2ft-lbs @ 6000rpm
Ignition – CDI
Transmission – 5-Speed, wet clutch, chain final drive
Frame – steel spine
Suspension – 27mm forks, twin dampers adjustable for preload
Wheels – 2.50 x 19, 3.00 x 16
Brakes – 110mm single leading shoe front and rear
Wheelbase – 1240mm
Seat Height - 790mm
Weight – 78kgs
Fuel capacity – 6.8ltrs inc 1ltr reserve
Top speed – 30mph

Honda MT50 Timeline

1980 MT50 S-A – Chassis number starting AD01-5000882
MT50F 1980 (A) AUSTRIA
MT50P 1980 (A) NETHERLANDS (with pedals)
MT50S 1980 (A) BELGIUM
MT50S 1980 (A) BELGIUM
MT50S 1980 (A) ENGLAND
MT50S 1980 (A) GERMANY
MT50S 1981 (B) BELGIUM
MT50S 1981 (B) BELGIUM
MT50S 1982 (C) NORWAY
MT50S 1982 (C) NORWAY
MT50S 1984 (E) AUSTRIA
MT50S 1984 (E) BELGIUM
MT50S 1984 (E) ENGLAND
MT50S 1984 (E) NORWAY
MT50S 1984 (E) NORWAY
MT50S 1984 (E) SWEDEN

1985 MT50 S-F chassis number starting AD01-5109771

1986 MT50 S-G chassis number starting AD01-5200034
MT50S 1986 (G) ENGLAND
MT50S 1987 (H) BELGIUM

1988 MT50 S-J chassis number starting AD01-5400001

1990 MT50 S-L chassis number starting AD01-5500002
MT50S 1990 (L) BELGIUM
MT50S 1990 (L) ENGLAND
MT50S 1990 (L) NORWAY
MT50S 1990 (L) SWEDEN
MT50S 1991 (M) SWEDEN
MT50S 1993 (P) NORWAY
MT50S 1993 (P) SWEDEN
MT50S 1996 (T) NORWAY
MT50S 1996 (T) SWEDEN

1980 MT50P (pedals) for the Netherlands
1990, note single seat and no rear foot pegs
MT50 fitted with aftermarket Fast Arrow 'radiator' covers (left side) - Pic Rasmus Steinwall
With Fast Arrow covers (right side) - pic Christoffer Thorstensson

See also
Honda MB5
Honda MT80


Swedish site MB/MT50:

Friday, 4 October 2019

Honda MVX250

Produced for just one year for the model year 1983, the MVX 250 was Honda’s first two-stroke road bike and was built to capitalise on Honda’s success in GP racing with Freddie Spencer’s title winning NS500. Like the NS500 it had a V3 engine, but, unlike the grand prix machine, the cylinder arrangement was the opposite, with the two outer cylinders laying forward horizontally and the middle cylinder standing vertically.

The MVX produced 40bhp and came in at 138kg dry, which was a little conservative when compared to the ground breaking 83 Suzuki RG250 which offered 45hp/ 131kg and an alloy frame. The MVX also featured Honda’s quirky in board front disc brake, handle bar fairing, belly pan and single seat converter.

The V3 engine featured a 1 vertical piston and two horizontal pistons (like the NS400R) which was the opposite of the race bike it was trying to emulate. To counteract vibration Honda made the vertical con rod thicker and heavier than the horizontal rods to act as a engine balancer. A series of engine failures saw the bike quickly retired and replaced with the much more advanced NS250, however the engine lived on with its issues resolved in the NS400R.

Model name MVX250F
Type · Grade -
Engine Operation 2 stroke
Model MC09
Displacement 249 cc
Release year 1983
Fuel Efficiency by Catalog -
Fuel Tank Capacity -
Fuel Supply Carburettor
Engine Type 2-stroke/Piston Lead Valve/Water-cooled/90-degree V-type 3-cylinder
Engine Starting Method -
Maximum Output (ps) 40ps(29kw)/9000rpm
Maximum Torque (kgf/m) 3.2kg・m(31.4N・m)/8500rpm
Vehicle Weight (Dry Weight) 138 kg
Vehicle Weight (Curb Weight) 155 kg
Length(mm)・Height(mm)・Width(mm) 1155 x 735 x 2010
Seat Height -
Front Tire Indication 100/90-16 54S TL
for Rear Tire Indication 110/80-18 58S TL


Model kit by Tamiya