Motobecane Engine Parts

January 16, 2019

AV7 Dc and AV7 Vc Engine Parts

under construction

Motobecane model 50 figure 1

  #   part#  qty  price   description  1. Engines, gaskets      
01   53444    1  N/A   engine 1-speed (20mph   6V ’76-77) 
01   53949    1  N/A   engine 1-speed (25mph   6V ’76-77) 
01   52341    1  N/A   engine variator (25mph   6V ’76-77) 
01   53744    1  N/A   engine 1-speed (30mph   6V ’74-77) 
01   53745    1  N/A   engine variator (30mph   6V ’74-77) 
01   54146    1  N/A   engine 1-speed (20mph 12V ’78-80) 
01   54147    1  N/A   engine 1-speed (25mph 12V ’78-80) 
01   54148    1  N/A   engine variator (25mph 12V ’78-80) 
01   54149    1  N/A   engine 1-speed (30mph 12V ’78-80) 
01   54844    1  N/A   engine variator (30mph 12V ’78-80) 
02   18568    1 $15.0 case bolt set 2 #2.1, 2 #2.2, 3 #2.3
2.1  15276    1 $0.90 bolt M7-1.25 x 45 flange (10 hex)
2.2  14936    1 $0.80 bolt M7-1.00 x 33 (10 hex)
2.3  00366    1 $0.90 bolt M7-1.00 x 48 (10 hex)
2.4  00366.1 1 $1.50 bolt M7-1.00 x 40 (set has 48)
2.5  00366    1 $0.90 bolt M7-1.00 x 48 (10 hex)
2.6  14936    1 $0.80 bolt M7-1.00 x 33 (10 hex)
2.7  15276    1 $0.90 bolt M7-1.25 x 45 flange (10 hex)
2.8  00011    5 $0.70 nut  M7 (10 hex)
03   14854    1 $9.00 gasket cylinder head 
04   14895    1 $8.00 gasket cylinder base
05   16910    1 $7.00 gasket crankcase
06   52646    1  N/A   gasket intake restricted (20mph)
06   17073    1 $7.00 gasket intake (25 and 30mph)
07   16912    1 $25.0 gasket kit

Motobecane model 50 figure 2

  #   part#  qty  price   description  2. Engine mounts      
01   19886    1 $6.00 bolt engine mount M8-1.00 x 140     
01   20453    1  N/A   bolt for up-exhaust
M8-1.00 x 145?  
02   20534    1 $4.00 spacer tube Ø8 x Ø14 x 18
03   17994    1 $11.0 Flexibloc right Ø8 x ∅32 x 23
04   19888    1 $3.00 ground cable, engine-to-frame
05   21014    2 $3.00 stepped spacer Ø8 x Ø12-17 x 10.5
06   20789    1 $11.0 Flexibloc left Ø11 ∅32 x 23
07   17523    1 $2.50 nut locking M8-1.00
08   16541    1 $0.20 washer Ø8
09   20790    1 $6.00 spacer tube plastic Ø8 x Ø11 x 23
10   17661    1 $3.00 bracket for variator cover
11   00011    4 $0.70 nut  M7 (10 hex)
12   01527    7 $0.50 lock washer Ø7
13   15276    2 $0.90 bolt M7-1.25 x 45 flange (10 hex)
14   14936    2 $0.80 case bolt
15   01526    2 $0.50 nut M6 special?
16   01172    2 $0.20 washer Ø6
17   17120    1 $5.00 bracket spring retainer variator
17   21282    1 $6.00 bracket spring retainer 1-speed
18   00968    2 $0.70 bolt M6 x ??
19   15933    2 $7.00 belt tension springs (each)
20   00366    2 $0.90 case bolt M7-1.00 x 48 (10 hex)
21   00010    2 $0.40 nut M6
22   15934    1 $9.00 Flexibloc lower Ø6 x Ø?? x ??
23   00050    1 $0.70 bolt M6 x 25? 
24   21709    1 $4.00 lower engine mount plate right
25   21710    1 $5.00 lower engine mount plate left
26   17354    1 $3.00 bracket variator cover

Motobecane 50 figure 3

  #   part#  qty  price   description  3. Cylinder and head
01   53505    1 $140. cylinder E with piston J (20 mph)
01   53505    1 $140. higher top deck, lower compression

01   23460    1 $180. cylinder AA w/piston AA (25 & 30)
01   23460    1 $180. cylinder AA w/piston AA (25 & 30)
01   23460    1 $180. cylinder C with piston C  (25 & 30)
01   23460    1 $180. cylinder C with piston C  (25 & 30)
01   23460    1 $180. cylinder C with piston C  (25 & 30)
01   23460    1 $180. cylinder E with piston E  (25 & 30)
01   23460    1 $180. cylinder E with piston E  (25 & 30)
01   23460    1 $140. cylinder C with piston C good-used
01   23460    1 $140. cylinder C with piston E good-used

02   14721    1 $12.0 decomp valve kit
03   14821    2 $10.0 piston ring (pre-6/76) Ø39 x 2.0 FG
03   22148    2 $12.0 piston ring (6/76-on) Ø39 x 2.0 GI
04   15094    1 $12.0 piston pin Ø13 x 30
05   00658    2 $2.00 piston pin clip Ø13
06   14854    1 $9.00 gasket cylinder head 
07   19885    1 $35.0 cylinder head complete
08   00053    2 $1.00 rivet for ID plate
09   21294    1  N/A   engine ID plate   
10   00059    1 $1.00 spark plug gasket ring
11   01547    1 $3.00 spark plug NGK B6HS
12   15025    1 $8.00 decomp valve bare
13   14919    1 $7.00 mounting lug
14   14855    1 $7.00 guide
15   14897    1 $7.00 gasket
16   14987    1 $4.00 washer
17   15007    1 $4.00 spring 
18   15099    1 $6.00 valve link
19   00018    1  N/A   cottor pin, use small bent nail
20   14895    1 $8.00 gasket cylinder base  
21   22156    1 $3.00 wire guide

Piston (at skirt) to cylinder clearance: new is 0.005 to 0.01 mm (0.0002 to 0.0004″), max is 0.05 mm (0.002″).
This is a very small clearance, measured at the bottom of the piston, allowed by the all-aluminum cylinder. 
Usually pistons are measured at the bottom skirt, called “lower” below, because when cold, that is the widest part.
The bottom is slightly wider than the top, because there is less material, and therefore less thermal expansion.
When the piston is hot, the bottom and top are the same. The whole piston expands, as does the cylinder. 
Motobecane measures just below the rings, called “upper” below. On these pistons lower is 0.02 mm bigger.
Motobecane original pistons have no marks on top, listed below as “(M)”. Inside has the M logo (some also AJ3). 

< Some vintage replacement pistons have this logo stamped on top, listed as “(Θ)”. Inside says FRANCE.
They also have a size letter stamped on top. These were original replacements from Motobecane USA.
Other vintage aftermarket have no logo on top, listed below as “(O)”.

Motobecane 50 figure 4

  #   part#  qty  price   description x upper/lower    4. Piston
73    22273       N/A    piston(M) W  38.92/38.94 for 38.95 cyl
74    22274      $75.0 piston(M) AA 38.93/38.95 for 38.96 cyl
75    22275      $75.0 piston(M) A   38.94/38.96 for 38.97 cyl
75.1 22275.1   $75.0 piston(Θ) A   38.94/38.96 for 38.97 cyl

76    22276      N/A    piston(M) C   38.95/38.97 for 38.98 cyl
77    22277      $75.0 piston(M) E   38.96/38.98 for 38.99 cyl
78    22278      $75.0 piston(M) G   38.97/38.99 for 39.00 cyl
79    22279      N/A    piston(M)  J   38.98/39.00 for 39.01 cyl
79.1 22279.1   $75.0 piston(Θ)  J   38.98/39.00 for 39.01 cyl

80    22280      N/A    piston(M)  L   38.99/39.01 for 39.02 cyl
81    22281      $75.0 piston(M) N   39.00/39.02 for 39.03 cyl
82    22435      $75.0 piston(M) P   39.01/39.03 for 39.04 cyl
82.1 22435.1   $75.0 piston(O)      39.09/39.11 for very worn

 

Motobecane 50 figure 5
left is for center-mount carb, right is side-mount

   #   part#  qty  price   description  5. Intake pipe
01   16673    1  N/A   intake pipe short (variator 25mph) Ø16
01   16619    1 $18.0 intake pipe short (var. 30 pre-3/77) Ø17
02   01176    3 $0.90 lock nut M6
03   01172    3 $0.25 lock washer Ø6
04   52646    1  N/A   intake gasket restricted (20mph)  
04   17073    1 $7.00 intake gasket (25 & 30 mph) 
05   00796    2 $2.50 stud M6 x 31
06   53496    1  N/A   intake pipe thin long (1-sp 20mph) Ø19
06   21201    1 $13.0 intake pipe long (1sp 25&30mph) Ø19
06   22899    1 $16.0 intake pipe long (var. 30 3/77-on) Ø19
07   21202    1 $6.00 support bracket
08   23018    1 $1.50 carriage bolt M6

 

 

Motobecane 50 figure 6

  #   part#  qty  price   description  6. Crank and case
01   19608    1  N/A   crankcase with seals (25 & 30)
1.1  19608.1 1 $15.0 left case half bare (25 & 30)
1.2  19608.2 1 $15.0 right case half bare (25 & 30)
1.3
  19608.3 1  N/A   crankcase (20mph) with a ridge that
1.3  19608.3 1  N/A   only allows a 20mph cylinder to fit

02   00011    4 $0.70 head nut M7-1.0 thick, 10hex
03   18921    4 $0.30 washer M7
04   14716    4 $4.00 cylinder stud
05   19089    2 $7.00 crank seal Ø15 x Ø21 x 4
06   54977    2 $14.0 special crank bearing 6302QR
07   15855    1 $15.0 needle bearing Ø13 x Ø16 x 14(13.6)
08   19609    1 $150. crankshaft Ø16 Ø15 pre-’80 for 6302QR
08   19609    1 $150. less threads for dome square-hole nut
8.1
  19609.1 1 $150. crankshaft Ø16 Ø15 ’80-on for 6302QR
8.1  19609.1 1 $150. more threads for large hex flywheel nut
8.2  19609.2 1 $150. crankshaft Ø15 Ø15 ’80-on for 6302
8.2  19609.2 1 $150. machined to take regular bearings

09
10
11
12
13

 

Crankshafts: top 19609, bottom 19609.2

Motobecane Crankshafts: are the same for variator and non-variator pulley-clutches.
Top is used, pre-1980, shorter right side threads. Takes special 16mm bearings 6302QR 16x42x13.
Bottom is new 1980-later original, machined to 15mm at bearings, to take ordinary bearings 6302 15x42x13.

Myrons offers new pre-1980 crankshafts, that take special 6302QR bearings.

Myrons offers a new original 1980-later crankshaft that has been machined from 16mm to 15mm at the center where the bearings press on. The press fit is precise and correct. The piston pin and needle bearing are new, included, and factory sealed in wax, that peels off. Two 6302 bearings, and two 15x21x4 seals are included. Price is $180.

It is long enough to take the 1980-later hex nut, sold separately at $10. But it will also take the pre-1980 square-hole nut, if the extra threads are ground off.

 

 

 

 

 

 

 

 


Motobecane Parts

August 18, 2012

updated 2021-01

Contents:  1. Parts Manuals   2. Parts Links

 

 

 

 


1. Parts Manuals

1974 Motobecane Dealer Notebook

1980 Motobecane Dealer Notebook

 

 

 

 

 

 

 

 

 

 

 


2. Where Motobecane parts are on this site:

 

xxxxxx Engine parts – BrandsFrance  / Motobecane / Engine Parts
xxxxxx Engine parts Parts   Engine  / Engine Hardware
xxxxxx Engine parts – Parts    /  Engine  / Bearings, bushings
xxxxxx Engine parts – Parts    /  Engine  / Seals, O-rings 

xxxxxx Frame parts –  Parts  /    Frame    / Gas Valves xx  use the index, most are A4
xxxxxx Frame parts – Parts /  F   rame     / Gas Caps xxxx  most are type screw-on 30 mm
xxxxxx Frame parts – Parts / F    rame     / Steering Parts scroll to 25 x 1 thread
xxxxxx Frame parts –  Parts  /    Frame    / Covers
 xxxxxxscroll to Motobecane
xxxxxx Frame parts –  Parts  /    Frame    / Reflectors
xxx  some are available, not listed

xxxxxx Frame parts –  Parts  /    Frame    / Seats
xxxxxxxxsome early solo seats, not listed
xxxxxx Frame parts –  Parts  /    Frame    / Shocks
xxxxxx  scroll to 280 x 8 x 8
xxxxxx Frame parts –  Parts  /    Frame    / Fork Parts
xxx  forks yes. but no boots, not listed

x   Carburetor parts – Parts / Carburetor / Gurtner xxxxxx scroll to Motobecane or Model 7

xxxx  Ignition parts – Parts  / Ign & Mag. / Ignition Parts  plug NGK BR6HS, other parts
xxxx  Ignition parts – Parts  / Ign & Mag. / Novi Magneto  2-coil 6V or 3-coil 12V, not listed

xxx  Electrical parts –  Parts  /  Electrical  / Switches xxxx  most are available, not listed
xxx  Electrical parts –  Parts   / Electrical  / Bulbs
xxxxxxx  use replaceable bulb headlight
xxx  Electrical parts –  Parts   / Electrical  / Head Lights
x  scroll to Luxor
xxx  Electrical parts –  Parts   / Electrical  / Tail Lights
xx   scroll to ULO
xxx  Electrical parts –  Parts   / Electrical  / Horns, Wiring
some available, none listed 
xxx  Electrical parts –  Parts   / Electrical  / Speedometer 
 scroll to Huret 

xxx   Controls parts –  Parts  /    Controls   / Motobecane

xxxxxx  Cable parts – Parts / Cables & Hw/     Cables     /   Motobecane Cables

xxxxx   Wheel parts –  Parts  /    Wheels   / Tires & Tubes
xxxxx   Wheel parts –  Parts  /    Wheels   / Wheel Parts
xxxxx   Wheel parts –  Parts  /    Wheels   / Brakes
xxxxx   Wheel parts –  Parts  /    Wheels   / Spokes

 

 

 

 

 Motobecane Carburetor Parts:

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

 Motobecane Cables:

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

 Motobecane Controls

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

 

 Motobecane Decompression Valve:

Motobecane Decompression Valve

Motobecane Decomp Valve