USEFUL DATA - ALL MODELS

 

 

Model

 

A7

Up to

Engine No.
ZA7 11192

A7 S.T.

Twin
Carburetters

A7

On and after

Engine No.
AA7 101.

A7S/T&S/S

On and after

Engine No.
AA7S 101

A10

 

R/R

and

S/R

Engine bore

62mm.

62mm.

66mm

68mm.

70mm

70mm

Engine stroke

82mm.

82mm.

72.6mm.

72.6mm.

84mm

84mm

Engine capacity

495 c.c.

495 c.c.

497 c.c.

497 c.c.

646 c.c.

646 c.c.

Petrol tank capacity

3 gal

3.5 gal

3.5 gal

3.5 gal

4.25 gal

2 or 4 gal

Oil tank capacity

4 pints

4 pints

4 pints

4 pints

4 pints

5.5 pints

Gearbox capacity

1 pint

1 pint

1 pint

1 pint

1 pint

14 fl ozs

Compression ratio

6.6 - 1

7 - 1

6.6 - 1

7.25 - 1

8.5 - 1

S/R

R/R

8.26-1

8-1

Clearances:

Inlet tappet(cold)

.015"

.015"

010"

008"

010"

008"

Exhaust tappet(cold)

.015"

.015"

.016”

.012”

.016"

.006”

Piston ring gap(plain)

.013"

.013"

.013"

.013"

.013"

 

Piston ring gap (oil control)

.011"

.011"

.011"

.011"

.011”

 

Piston ring side clearance

.002”/.004”

.002”/.004”

.002”/.004”

.002”/.004”

.002”/.004”

.002”/.004”

Piston clearance —
bottom of skirt

.003”/.005"

.003”/.005"

.003”/.005"

.003”/.005"

.003”/.005"

.003”/.005"

 

Gear ratios:

S/T

S/S

 

Top

5.1

5 1

5 1

5.0

5.28

4.42

4.53

3rd.

6.2

6.2

6.2

6.05

6.38

5.36

5.48

2nd.

9.0

9.0

9.0

8.8

9.28

7.77

7.96

1st.

13.2

13.2

13.2

12.9

I3.2

11.41

1168

Carburetter:

Jet size

-

110

-

-

-

250

With air cleaner

140

-

140

160

170

240

Sparking plugs:

Cast Iron head

L.10S

L.10S

L.10S

L10S

L.10S

NA 10

Alloy head

           

Plug points gap

.015” to .018”

.015” to .018”

.015” to .018”

.015” to .018”

.015” to .018”

.018” to .020”

Timing:

 

Inlet valve:

Opens before T.D C.

24

24

30

42

30

42

Opens after B.D.C.

65

65

70

62

70

62

Exhaust valve:

Opens before B.D.C.

60

60

65

67

65

67

Opens after T.D.C.

21.5

21.5

25

37

25

37

Ignition setting
(inches before T.D.C. fully advanced)

3/8”

3/8”

5/16"

3/8”

11/32"

3/8”

Magneto points gap

.012"

.012”

.012”

.012"

.012"

.012"

Tyres:

Size (front)

3.25x19

3.25x19

3.25x19

3.25x19

3.25x19

 

Size (rear)

3.50x19

3.50x19

3.50x 19

3.50x19

3.50x19

 

Pressure front (PSI)

17lb

17lb

17lb

17lb

17lb

17lb

Pressure rear (PSI)

18lb

18lb

18lb

18lb

18lb

18lb

 

NOTE. Standard A7's after Engine No. CA7 5282 and Standard A10’s After Engine No. DA10 1647 have the same camshaft as the S/S and R/R machines and valve timing is therefore the same.

 

 

PISTON CLEARANCES

 

To avoid the possibility of seizure or piston tap, pistons must be fitted with adequate but not excessive clearance.

The following are the recommended total clearances between the bottom of the piston and the cylinder wall.

 

       

A7.

 

6.7 : 1

.002"/.004"

(Split skirt)

6.7 : 1

.0011"/.0031"

 

7.25 : 1

.002"/.004"

(Split skirt)

7.25 : 1

.0011"/.0031"

A7.

(Star twin)

 

.002"/.004"

A7.

(Split skirt)

Star twin & Shooting star

.0011"/.0031"

A10.

(Golden Flash)

6.5 : 1

.003"/.0045"

(Split skirt)

6.5 : 1

.0025"/.0045"

(Split skirt)

7.25 : 1

.0025"/.0045"

A10.

(Super flash & Road Rocket)

8 : 1

.003"/.0045"

A7.

(Shooting star)

8 : 1
(after eng. No. CA7S.S.4501)

.0035".005"

A10.

(Golden Flash)

7.5 : 1
(after eng. No. DA10-651)

.0035"/.005"

A10.

(Super rocket)

8.5 : 1
(after eng. No. CA10R6001)

.004"/.0055"