Laura M48 Parts

updated 2021-09

Contents:
1. M48 Versions
2. M48 Parts
3. M48 Parts Info

 

 


 

1. Laura M48 Versions

1972 versions kmh (XX)  1976 USA 00 mph  1978 USA
M48-01  40 kmh (XX)  M48-01  25 mph    M48-11B  25 mph
M48-02  50 kmh (XX)  M48-02  30 mph    M48-02    30 mph
M48-03  30 kmh (CH)  M48-03  20 mph    M48-13B  20 mph
M48-04  30 kmh (DK) (S)
M48-05  25 kmh
M48-08  45 kmh

 

 

 

 


2. Parts for Laura M48 Engine

The parts list below is made from all three versions (20, 25, 30 mph) of the Batavus USA Spare Parts Catalogs shown at right, for models 1976-80 VA, HS50, Mo-bat, Bronco, Starflite VA I, Starflite VA II, Starflite HS.

1970’s USA Batavus dealers were given parts books only for their state’s speed version, and not other state’s. So a dealer in 25mph state like Arizona did not know, and could not easily find out, what parts were different in a 30mph state like California. There were just a few pages that were different.

Price color: new  used   Part color: 25,30mph  20mph

 

#   part# qty price  description

1.  480201none  Batavus decal
2.  480200 2  $19.0 engine cover
3.  540292$3.50 cover tab (rubber)
4.  820502 2  $0.50 hex bolt M5x15
5.  843500$0.10 lock washer M5
6.  480981 1  $15.0 support plate
7.  480980 1  $22.0 start lever
8.  827500 6  $0.25 hex nut M5
9.  843500 6  $0.10 lock washer M5
10 480890 1  $12.0 locking plate
11 48088260-25 end plate w/button
12 480824none  start button
13 480883 1  $8.00 start spring
14 480889 1  $15.0 friction plate
15 480683none  exhaust gasket
16 828010$4.00 hex nut M10-1.0×6
17 840010$8.00 tab washer M10
18 480886 1  $25.0 weight-spring ring
19 810081$10.0 ball bearing 6302 15x35x11
20 820520 6  $5.00 splined bolt M5x27
21 480881none  alum. hub w/ steel saucer
21a 00000$35.0 steel saucer only
22 480887 1  $8.00 saucer spring  12x28x1.0
23 816180none  felt oil ring 15x21x3
    substitute  $6.00 oil seal 15x21x3
24 813081$20.0 needle bearing 15x21x22
25 816480none   left crank seal 20x42x7 offset
26 841512 1  $8.00 crank circlip Ø42×1.75 inner
27 838045 2  none  dowel roll pin Ø5×12
28 480181none  case gasket
29 480381 1  $90.0 crankshaft
30 480325 1  $12.0 piston bushing Ø11.6x14x11
31 841520$1.50 piston pin clip Ø12
32 480501$10.0 piston pin Ø12 x 33
33 480580 1  $60.0 piston assy Ø40×18-12-14
34 480502$10.0 piston ring Ø40 x 1.5 FG
35 480682$6.00 base gasket
36 829680$7.50 cylinder stud M6 x 115
37 847600 4  $0.20 plain washer M6
38 846600$0.20 lock washer M6
39 827600 4  $0.50 hex nut M6 x 6
40 481890$6.00 spark plug cap NGK black
41 490814 1  $8.00 clutch washer 15x28x0.5
42 830000$1.50 flywheel key 3 x 5mm
43 848011 1  $0.20 plain washer M10
44 828000 1  $0.50 tooth washer M10
45 828000 $2.00 nut M10-1.0×10
46 816181 1  $12.0 oil seal 14x30x7
    substitute  $7.00 oil seal 15x30x7

47 823506 6  $0.80 case screw M6 x 25?
51 820603 1  $0.50 hex bolt M5x??
52 843600 1  $0.20 lock washer M5
53 481784$7.00 inlet gasket
54 481783$49.0 reed valve 4-petal
55 813086 2  $0.00 needle bearing Ø16
56 481591none  pulley dust cover
58 481786 1  $0.00 dirt splash shield
59 481797 2  $0.00 step washer M5
60 820500$0.60 hex bolt M5 x 12
61 480892 1  $8.00 clutch leaf spring
63 540898 1  $25.0 pressure plate used
64 485194 1  none  crankcase (20mph)
64 485180 1  $0.00 crankcase (25 & 30)
65 480695 1  none  cylinder head (20 & 25)
65 485695 1  $0.00 cylinder head (30mph)
66 485697 1  none  cylinder (20mph)
66 485690 1  $0.00 cylinder (25 & 30)
67 481883 1  $3.00 spark plug NGK B5HS
70 480185 1  $0.00 grommet for wires
71 480894 1  none  pulley-housing-thin (20)
71 480880 1  $150  pulley-housing (25 & 30)
72 486795 1  none  carb. assy 8mm (20mph)
72 481790 1  none  carb assy 8mm (25mph)

72 541780 1  none  carb assy 12mm (30mph)
73 481794 1  none  ntake pipe (20mph) Ø6
73 481785$25.0 intake pipe (25 & 30) Ø11
74 481594 1  none  pulley with 11T (20mph)
74 481598$70.0 pulley with 13T (25 & 30)
75 480893 1  none  v-belt thin long(20mph)
75 480891 1  $21.0 v-belt thick (25 & 30) Gates XL-9319
76 481091 1  none  sprocket 11T (20mph)
76 481093 1  $0.00 sprocket 13T (25 & 30)
77 481506 1  none  tab nut (20mph)
77 481505 1  $0.00 tab nut (25 & 30)
79 480899 1  $8.00 clutch washer (25,30) 12x24x0.5
00 480899a   $5.00 clutch washer thicker 12x24x0.8

 


3. M48 Engine Parts Information

Batavus M48 Clutch Small Parts

Batavus M48 Clutch Small Parts

Small clutch parts: Most of the small clutch parts are in this photo.

Top row, #17 840010 tab washer, #4 820502 hex bolt, #5 843500 washer, #6 480981 plate, #61 480892 leaf spring, #22 480887 saucer spring (used), #20 820520 splined bolt.

Bottom row, #24 813081 needle bearing, #23 816180 felt ring, #41 490814 washer, #22 480887 saucer spring, #79 480899 washer.

Saucer spring: You can see the shiny rings on the used saucer spring. They are where the contact was. The dark areas never touch anything. 

Leaf spring: The leaf spring goes on any one of the ten tabs of the friction plate, under the basket. What it does is reduce vibration. It stops the jingle bells sound, and helps the friction plate tabs last longer. It is not essential, but very beneficial. 

Crank Seals: Laura M48 uses crank seals that are 1 mm smaller (tighter) than normal.  The 15mm right side has a 14x30x7 seal. The 21mm needle bearing case on the left side has a 20x42x7 special seal with an offset lip. 

Friction Plate #480889: 10 tabs, each 10.5mm wide, inner diameter 58.5mm, outer diameter 92.4mm (100.4mm at tabs), thickness 3.65mm.

Note: The tabs break off when the slots in the basket become worn or notched on one side. This is because not all ten tabs are sharing the load evenly. A worn clutch housing/basket also makes the clutch stick and not go into “neutral”.  

Pulley-Housing #480880: 10 tabs, 10.3mm wide, ID 94.0mm, OD 98.6mm, center needle bearing ID 15.0mm, OD 21.0mm, length 22.0. Comes with the needle bearing only. Price $150 new, $100 almost new not worn. Far left, a new one and a worn out one. The slots for the tabs get worn wider where the plate tabs push at. Filing those flat will help, but it might still stick sometimes.

 

Pulley-Housings: 480880 (painted red) has a wide pulley for US 25, 30 mph and Euro 40, 45, 50 kmh versions. 480894 (painted yellow) has a thin pulley for US 20 mph and Euro 25, 30 kmh versions. 480880 red is deeper (25.5 mm) than 480894 (24.4mm).

480880 and 480894

Left 480880, R 480894

480880 clutch housing with pulley

480880 clutch housing
25.5 mm deep at crank

480894 clutch housing with thin pulley

480894 clutch housing
24.4 mm deep at crank

 

 

 

 

 

 

 

 

 

 

Clutch Washers: The Batavus crank goes from 12mm to 15mm right at the edge of the needle bearing. The clutch needle bearing is lubed by the gasoline and oil mist in the crankcase. The three special steel washers, one cupped, seal the crankcase pressure on the spinning crankshaft, along with the rubber crank seals.

 

First the felt ring #23 goes into a recess in the housing-pulley #71. Then the large 15mm washer #41 goes on, just over the 12-15 step in the crankshaft. Then the 12mm saucer spring #22 goes on with the dish side up (outward). Then on 25 and 30 mph versions with the brick red pulley, the 12mm small washer #79 goes on, into the dish of the saucer spring. Then the aluminum clutch hub with large steel saucer in back goes onto the flat sided part of the crank, and rests against the #41. When the outer nut is tightened, the saucer spring is compressed slightly, so that the crankcase is sealed by the metal-to-metal contact ring between #79 and #22. When the engine is running, but the rear wheel is stopped, #79 spins, but #41 is stationary. Once the bike gets over 10mph, #41 and #79 are both spinning in sync, so the metal-to-metal pressure seal gets better.

 

Crankcase Pressure Leaks: All of this special washer business allows the needle bearing to never need greasing. But if a washer is missing, there is a small pressure leak. A small crankcase pressure leak causes a small loss of engine power at low speeds.

On a two-stroke crankcase the leak alternates in both directions. Piston going down causes some fuel mist to get pushed out. Piston going up causes some fresh air to get sucked in. Then the cycle repeats. Because of the rapid reversal of direction, at low engine speeds the leak has more time to happen, due to inertia. So the effect of leaving out one of the washers is to cause less “low-end torque”. The engine is weak until it gets going fast, then it is normal but lean.  

There is a small grease seal in the needle bearing #24. But it is not a pressure seal with a ring spring. So it is sealed partially, even without the washers. That is why leaving out the washers only causes a small loss of low speed power.

 

Engine Covers:

Laura M48 magneto (right) and clutch (left) covers are the same. There are different versions, including aftermarket, and different stickers.

Motobecane, Laura Batavus, Laura Badger, TYM Angel, TYM Speed Bird magneto covers all interchange, because they all have a 124 mm inner diameter. 

Motobecane magneto cover

’70’s Motobecane

Batavus clutch cover

1970’s Batavus

 

 

 

 

 

 

 

 

Laura engine cover

1970’s Laura

Angel

1970’s TYM Angel

 

 

 

 

 

 

 

Batavus M48 with late Motobecane magneto cover

Aftermarket engine cover

This is an aftermarket 124mm ID engine cover for an ’80’s Motobecane. You can see it looks slightly different but fits Batavus. Price $18 with two rubber fastener tabs.