|
BSA SERVICE SHEET No. 428 |
Reprinted October. 1964 |
|||
|
USEFUL DATA |
C15 |
CI5T |
C15S |
Cl5 |
|
Engine Number |
Left-hand side of the engine below cylinder | |||
|
Frame Number |
At the top of the steering head tube | |||
|
ENGINE: |
||||
|
Capacity (c.c.) |
249 |
249 |
249 |
249 |
|
Cylinder bore (mm.) |
67 |
67 |
67 |
67 |
|
Stroke (mm.) |
70 |
70 |
70 |
70 |
|
Compression ratio |
8 to 1 |
8 to 1 |
10 to 1 |
8.75 to 1 |
|
Inlet opens B.T.D.C. |
26 |
41.5 |
41.5 |
51 |
|
Inlet closes A.B.D.C. |
70 |
62.5 |
62.5 |
68 |
|
Exhaust opens B.B.D.C. |
61.5 |
62.5 |
62.5 |
78 |
|
Exhaust closes A.T.D.C |
34.5 |
41.5 |
41.5 |
37 |
|
Piston rings (compression) (in.) |
0.0625 wide |
0.0625 wide |
0.0625 wide |
0.0625 wide |
|
Piston rings (scraper) (in.) |
0.125 wide |
0.125 wide |
0.125 wide |
0.125 wide |
|
Piston ring gaps: |
||||
|
Minimum (in.) |
0.009 |
0.009 |
0.009 |
0.009 |
|
Maximum (in.) |
0.013 |
0.013 |
0.013 |
0.013 |
|
Sparking plug |
N5 Champion |
N5 Champion |
N3 Champion |
N4 Champion |
|
Plug points gap: |
||||
|
Minimum (in.) |
0.02 |
0.02 |
0.02 |
0.02 |
|
Maximum (in.) |
0.025 |
0.025 |
0.025 |
0.025 |
| After Engine C15T-1251 and C15S-2112 valve timing is:- | ||||
|
Inlet opens B.T.D.C. |
51 deg |
|||
|
Inlet closes A.B.D.C. |
68 deg |
|||
|
Exhaust opens B.B.D.C. |
78 deg |
|||
|
Exhaust closes A.T.D.C. |
37 deg |
|||
|
TRANSMISSION: |
||||
|
Gear ratios--Top |
5.98 |
9 |
9 |
6.36 |
|
Third |
7.65 |
14.67 |
10.8 |
7.64 |
|
Second |
10.54 |
22 |
14.94 |
10.54 |
|
First |
15.96 |
28.53 |
19 |
13.44 |
|
Clutch friction plates |
4 |
4 |
4 |
4 |
| Clutch Spring Free Length | 1.66" | 1.66" | 1.66" | 1.66" |
|
Chain sizes-Front (in.) |
3/8 Duplex |
3/8 Duplex |
3/8 Duplex |
3/8 Duplex |
|
(70 pitches) |
(70 pitches) |
(70 pitches) |
(70 pitches) |
|
|
Rear (in.) |
1/2 x .335 |
1/2 x .335 |
1/2 x .335 |
1/2 x .335 |
|
(112 pitches) |
(122 pitches) |
(122 pitches) |
(112 pitches) |
|
|
Teeth on--Engine sprocket |
23T |
23T |
23T |
23T |
|
Gearbox sprocket. |
17T |
15T |
15T |
16T |
|
Clutch sprocket |
52T |
52T |
52T |
52T |
|
Rear chain wheel |
45T |
60T |
60T |
45T |
| Alternatives:- Gearbox Sprockets 17, 18, 19 & 20 Rear chain wheel 52, 56 & 60 | ||||
|
CAPACITIES: |
||||
|
Fuel tank (galls.) |
3 |
2 |
2 |
3 |
|
(13.6 Ltr) |
(9 Ltr) |
(9 Ltr) |
(13.6 Ltr) |
|
|
Oil tank (pints) |
4 |
5 |
5 |
4 |
|
(2 1/4 Ltr) |
(2.8 Ltr) |
(2.8 Ltr) |
(21/4 Ltr) |
|
|
Gearbox (pints) |
2/5 (220cc.) |
2/5 (220cc.) |
2/5 (220cc.) |
7/16 (250cc.) |
|
Front forks (pints) |
1/6 (100cc.) |
1/3 (190cc.) |
1/3 (190cc.) |
1/6 (100cc.) |
|
Primary chain case (pints) |
1/4 (140cc.) |
1/4 (140cc.) |
1/4 (140cc.) |
1/4 (140cc.) |
| After engine C15-26792 & B40-2402 the gearbox capacity was increased to 1/2 pint (285cc) | ||||
|
WHEELS: |
C15 |
C15T |
C15S |
C15 |
|
Rim size Front |
WM2-17 |
WM1-20 |
WM1-20 |
WM2-17 |
|
Rim size Rear |
WM2-17 |
WM3-18 |
WM3-18 |
WM2-17 |
|
Tyre size Front |
3.25-17 |
3.00-20 |
3.00-20 |
3.25-17 |
|
Tyre size Rear |
3.25-17 |
4.00-18 |
4.00-18 |
3.25-17 |
|
Brakes, dia. x width: |
||||
|
Front (in.) |
6x7/8 |
7 x 1 1/8 |
7 x 1 1/8 |
6x7/8 |
|
Rear (in.) |
6x7/8 |
6x7/8 |
6x7/8 |
6x7/8 |
| Rim Offset (Front & Rear) | 5/32 | 5/32 | ||
| Hub Outside Diameter | 7 | 7 | ||
| Hub Spoke Width | 2 1/4 | 2 1/4 | ||
| Spoke Length (below the head) | 5 7/16 | 5 7/16 | ||
| Spoke Dia | 10Gauge (1/8) | 10Gauge (1/8) | ||
|
CARBURATION (AMAL): |
||||
|
Bore (in.) |
7/8 |
7/8 |
1.0625 |
1 |
|
Main jet |
140 |
140 |
190 |
200 |
|
Pilot jet |
25 |
25 |
25 |
25 |
|
Throttle valve |
375/4 |
375/4 |
376/3.5 |
376/4 |
|
Needle position |
3 |
3 |
2 |
2 |
|
Needle jet |
0.1055 |
0.1055 |
0.106 |
0.106 |
|
GENERAL DETAILS: |
||||
|
Front suspension movement (in.) |
5 |
5 |
5 |
5 |
|
Rear suspension movement (in.) |
2.375 |
2.375 |
2.375 |
2.375 |
|
Generator output |
60 watts |
60 watts |
60 watts |
60 watts |
|
Contact breaker gap (in.) |
0.015 |
0.015 |
0.015 |
0.015 |
|
Battery capacity |
13 amp/hr at 20 hr rate |
13 amp/hr at 20 hr rate |
||
|
Overall length |
78 |
81 |
81.5 |
78 |
|
Wheelbase (in.) |
51.25 |
51.75 |
51.75 |
51.25 |
|
Ground clearance (in.) |
5 |
7.25 |
7 |
5 |
|
Saddle height (in.) |
30 |
33 |
32 |
30 |
|
Overall height (in.) |
37 |
42 |
41.5 |
36 |
|
Handlebar width (in.) |
26 |
31.125 |
31.125 |
27 |
|
Steering head angle |
65 deg |
63 deg |
63 deg |
65 deg |
|
Steering lock angle |
50 deg |
60 deg |
60 deg |
50 deg |
|
Weight (lbs.) |
275 |
265 |
265 |
275 |
|
Tyre pressures Front (lbs.) |
16 |
19 |
19 |
17 |
|
Tyre pressures Rear (lbs.) |
22 |
16 |
16 |
21 |
|
The recommended inflation pressures are based on a riders weight of 140 lb. Increase the tyre pressures as follows, If the rider's weight exceeds 140 lb. |
||||
|
Front tyre: Add one lb. per square inch for every 28 lb. increase above 140 lb. |
||||
|
Rear tyre: Add one lb. per square inch for every 14 lb. increase above 140 lb. |
||||
|
If a pillion passenger or luggage is carried, the actual load bearing upon each tyre should be determined and the pressures increased in accordance with the Dunlop Load and Pressure Schedule. |
||||
Source: Cedric Norman Archive, which explains minor modifations to the specs due errors in the original BSA publication.
