Motobecane

August 18, 2012

Welcome.

Info Motobecane 1976

Info Motobecane 1976

Info Motobecane 1978

Info Motobecane 1978

Info Motobecane 1980

Info Motobecane 1980

 

 

 

 

 

 

 

 

 

 

 

 

 

1974-76 Motobecane 40TS

74-6 Motobecane 40TS
1 speed Dimoby trans.
hard tail, 2.00×17 tires
no speedo, no fork lock
narrow painted fenders
US model round HL
’74-75 only yellow

1974-76 Motobecane 40TS

1974-76 Motobecane 40TL
one speed Dimoby trans.
hard tail, 2.00×17 tires
with speedo, fork lock
narrow stainless fenders
US model round headlight
’74-75 only yellow

1975-76 Motobecane 40TL

1975-76 Motobcane 40TL
one speed Dimoby trans.
hard tail, 2.00×17 tires
with speedo, fork lock
narrow stainless fenders
Euro model square HL
colors: orange or yellow

Motobecane 40TL

Motobécane
Mobylette 40TL
one speed Dimoby trans.
hard tail, 2.00×17 tires
speedo, lock, ss fenders
Euro model small HL
colors: coral or white

 

 

 

 

 

 

 

 

 

 

1974-76 Motobecane 50S rear shocks, 2.25x17 tires with speedometer painted yellow fenders US model round headlight '74-75 yellow only

1974-76 Motobecane 50S
rear shocks, 2.25×17 tires
with speedo, solo seat
painted yellow fenders
US model round headlight
’74-75 yellow only

1974-77 Motobecane 50L

1974-77 Motobecane 50L
one speed Dimoby trans.
rear shocks, 2.25×17 tires
solo seat,ss,sp,US model
74-5 yellow 76-7 orange

1974-77 Motobecane 50VL variator transmission

74-77 Motobecane 50VL
Variator (2-speed) trans.
rear shocks, 2.25×17 tires
solo seat, SS F fender
US model round headlight
74-5 yellow 76-7 orange

Motobecane Mobylette Series 50

Motobécane
Mobylette Series 50
Dimoby or variator trans
rear shocks, 2.25×17 tires
speedo, lock, solo seat
Euro models square HL

 

 

 

 

 

 

 

 

 

 

1976-77 Motobecane 50L

1976-77 Motobecane 50L
one speed Dimoby trans.
rear shocks, 2.25×17 tires
6V lites, speedo, lock
solo seat, chrome rack
SS F fender, US model
colors: orange or yellow

1976-77 Motobecane 50V

1976-77 Motobecane 50V
Variator (2-speed) trans.
6V lites, 2.25×17 tires
solo seat, SS F, US model
colors: orange or yellow

1978-79 Motobecane 50V variable (2-spd) trans. 12V lites candy red, blue silver

1978-79 Motobecane 50V
variable (2-speed) trans.
12V lites, 2.25×17 tires
solo seat, SS F, US model
candy red, blue silver

1978-79 Motobecane 50VL

78-79 Motobecane 50VLC
variable (2-speed) trans.
12V lites, 2.25×17 tires
solo seat, SS F, US model
candy red, blu-sil, copper

 

 

 

 

 

 

 

 

 

 

1978-79 Motobecane 7

1978-79 Motobecane 7
one speed Dimoby trans.
hard tail, 2.00×16 tires
12V lites, rear gas tank
solo seat, US model

1978-79 Motobecane 50VLA

78-79 Motobecane 50VLA
Variator (2-speed) trans.
12V lites, 2.25×17 tires
long seat, SS F, US model
aluminum wheels

1978-79 Motobecane 50VLX

78-79 Motobecane 50VLX
Variator (2-speed) trans.
12V lites, 2.50×17 tires
solo seat, US model
off road adventure model

Motobecane ID plate has 4 silver squares: 12 79 50V B

ID has 4 stamps:
12__79__50V__B
(Dec ’79 25mph)

 

 

 

 

 

 

 

 

 

 

1979 Motobecane Moby Variator (2-speed) trans. 12V lites, 2.25×17 tires solo seat, US model candy red, blu-sil, copper

1979 Motobecane Moby
Variator (2-speed) trans.
12V lites, 2.25×17 tires
solo seat, US model
restored by B. Small

1980 Motobecane Traveler

’80 Motobecane Traveler
1 speed Dimoby trans.
rear shocks, 2.00×17 tires
with speedo, solo seat
US model round headlight
colors: yellow or silver

1980 Motobecane Moby

1980 Motobecane Moby
Variator (2-speed) trans.
12V lites, 2.25×17 tires
long seat, US model
candy red, blu-sil, copper

1980 Motobecane Le Moped

80 Motobecane Le Moped
Variator (2-speed) trans.
12V lites, 2.25×17 tires
long lift-up seat, US model
gold aluminum wheels

 

 

 

 

 

 

 

 

 

 

On the frame behind the headlight is the ID plate. The lower squares say model (left) and speed version (right), stamped in. Before 1980, A=30, B=25, C=20. From 1980 on, A=20, B=25, C=30. Before 1978, no letter, just 20, 25, or 30 (mph). Hope yours is a 30! 1980 was the last year for US models. 1981 had new 17 digit VIN and new EPA and DOT noise and safety regulations. That  was “the last straw”. 

1978 Motobecane Logo

1978 Motobecane Logo

Welcome. Myron’s Mopeds carries Motobecane moped parts, for 1970’s US models. Motobecane has made many other models, a model line, and millions sold, for every major country in Europe and on most of the Earth. The quantity of 1970’s USA mopeds is less than 10% of all Motobecanes world wide since the 1920’s. All of the US models use the “Moby” engine, aka “AV7”, piston port, two transfers, rubber mounted. Motobecanes from earlier or later times or from other countries, are not included here.

 

Motoconfort

Motoconfort is a branch

1932 Motobecane Logo

1932 Motobecane Logo

Motobecane  began in 1922 as two French engineers, Charles Benoit and Abel Bardin. They made the name from “moto” French slang for motorcycle, and “bécane” French slang for bicycle. In the 1950’s, Motobecane pioneered the dual action clutch system, where one clutch makes the engine start when the rear wheel speed becomes fast enough, and the other clutch makes the bike move forward when the engine speed becomes high enough. They called this dual system “Dimoby”. It means “one speed dual auto clutch”. What’s confusing is the variator models (two speed, dual auto clutch) were not called Dimoby. Motobecane has a division called Motoconfort. That name appears on some of the original parts and packaging. It is easy to confuse “comfort” and “con fort” (with force). Remember Motobecanes have strength, not comfort!   

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 Motobecane Carburetors:

They are now located in Carburetors > Gurtner > Motobecane. Click to go there.

 Motobecane Cables:

They are now located in Cables > Motobecane. Click to go there.

 Motobecane Controls

They are now located in Controls > Motobecane. Click to go there.

 

 Motobecane Decompression Valve:

Motobecane Decompression Valve

Motobecane Decomp Valve

 

 

 

 

 

 

Motobecane USA Speed Versions Table


20 mph Dimoby (1-speed)   01-1976 to 12-1978

54115 Side mount AR2-10-910 carburetor (10mm)
53496 Intake pipe (Ø10 restricted)
52646 Intake gasket (20mph)
53505 Cylinder (20mph)
22914 Dual clutch with fixed front pulley
14756 Drive belt
16653 Rear pulley with 11 tooth front sprocket
18368 Motor chain 99 links
53873 Rear sprocket 48 tooth (11/48 = 0.229 ratio)

25 mph Dimoby (1-speed)   01-1974 to 12-1980

22160 Side mount AR2-12-729 carburetor (12mm)
21201 Intake pipe (Ø12)
17073 Intake gasket
54328 Cylinder (25mph)
22914 Dual clutch with fixed front pulley
14756 Drive belt
18940 Rear pulley with 12 tooth front sprocket
17693 Motor chain 96 links
20090 Rear sprocket 44 tooth (12/44 = 0.273 ratio)

30 mph Dimoby (1-speed)  01-1974 to 12-1980

22160 Side mount AR2-12-729 carburetor (12mm)
21201 Intake pipe (Ø12)
17073 Intake gasket
22335 Cylinder (30mph Dimoby)
22914 Dual clutch with fixed front pulley
14756 Drive belt
20731 Rear pulley with 13 tooth front sprocket
18427 Motor chain 97 links
20090 Rear sprocket 44 tooth (13/44 = 0.295 ratio)


25 mph Variator (2-speed)  03-1977 to 12-1980

52175 Center mount AR2-10-991 carburetor (10mm)
16673 Short intake (Ø10 restricted)
17073 Intake gasket
54328 Cylinder (25mph)
22921 Dual clutch with variable front pulley
14756 Drive belt
16653 Rear pulley with 11 tooth front sprocket
17785 Motor chain 102 links
20093 Rear sprocket 54 tooth (11/54 = 0.20 in low, 0.28 in high)

30 mph Variator (2-speed)  01-1974 to 03-1977

20026 Center mount AR2-12-705 carburetor (12mm)
16619 Short intake (Ø12)
17073 Intake gasket
23460 Cylinder (30mph variator)
22921 Dual clutch with variable front pulley
14756 Drive belt
16653 Rear pulley with 11 tooth front sprocket
17785 Motor chain 102 links
20093 Rear sprocket 54 tooth (11/54 = 0.20 in low, 0.28 in high)

30 mph Variator (2-speed)  03-1977 to 12-1980

54973 Side mount AR2-12-873 carburetor (12mm)
22899 Intake pipe (Ø12?)
17073 Intake gasket
23460 Cylinder (30mph variator)
22921 Dual clutch with variable front pulley
14756 Drive belt
16653 Rear pulley with 11 tooth front sprocket
17785 Motor chain 102 links
20093 Rear sprocket 54 tooth (11/54 = 0.20 in low, 0.28 in high)


Discussion:

This information is mostly from the Motobecane USA Parts Catalog, a big blue plastic 3-ring notebook from 1978-79.

Porting: The deepest secret is that there are four different cylinders, all identical on the outside. The different cylinders could have different port widths and heights (duration’s). Much more needs to be learned and explained. Why does a 2 hp one-speed model have a different cylinder than a 2 hp variable speed model?   

Gearing: The drive belt is the same for all versions. The 1-speed front pulley is the same for all versions. The 2-speed front pulley is the same for all versions. The rear pulley (without the front sprocket) is the same for all versions. Therefore, the pulley ratio is the same for all versions. The variator models in “low gear” have the same pulley ratio as the Dimoby models. As the rear wheel speed increases, the variator makes the front pulley bigger. The engine swings back as the front pulley grows, until it is in “high gear”. In high gear the pulley is about 40% bigger. So even though the variator models are geared low (small front and large rear) in chain sprockets, the variator makes up for it, above 18mph, by making the overall gearing about the same. 

 


More Motobecane parts being organized …