A.J.S. A.J.S. models 14,14S,14CS, 14CSR, 8 (light 350) and 7R all employ crankpins that are rather slender and which are subject to frequent breakage. To overcome this difficulty Alpha Bearings can bore out the flywheels and fit oversize crankpins that are most satisfactory in service. Alpha Bearings also offers a range of two part crankpins for engines employing: AMC5, AMC6, AMC7, AMC8 AMC12L, AMC12S, AMC12LX & AMC20. The use of the conversion pin AMC12LX is strongly advised for 7R engines. The exact point when the AMC5 was replaced by the larger AMC6 is not certain. Please check the press fit dimension to make certain the correct replacement bearing is ordered.

250 cc

Year

Model

Con rod casting No.

Big end Part No.

Cage Part No

Small end Part No.

MAIN BEARINGS

Drive Side

Timing Side
1930-33 33-12,R12, S12, T12 (ohv)

WHT.K

AMCS1

-

-

-

-

-

-
1935-40 22SS, 22T, 22, 12, 12M & Silver Streak (ohv)

WHT

AMC4

-

-

-

-

-

-
1958-60 14, 14CS .. .. .. .. .. .. .. .. .. ..

WHT

AMC14

K50

SE143

LS9

LS9

042239
1961-63 14, 14S, from engine No.

-

AMC14L

K50

SE143

RLS9

MS10

042239
1961-66 14CS, 14CSR.. .. .. .. .. .. .. ..

043021

AMC17H

K51

SE143

RLS9

MS10

042239

350 cc

Year

Model

Con rod casting No.

Big end Part No.

Cage Part No

Small end Part No.

MAIN BEARINGS

Drive Side

Timing Side

-

Side Valve models

-

-

-

-

-

-

-

-
1930 M4, R4 .. .. .. .. .. .. .. .. .. ..

SXSB

AMCS2

-

-

-

-

-

-
1931 S4, S5 .. .. .. .. .. .. .. .. .. ..

-

AMCS2

-

-

-

-

-

-
1932-34 33-5, 34-5 .. .. .. .. .. .. .. .. .. ..

WHT

AMCS1

-

-

-

-

-

-

-

 O.H.V. models

-

-

-

-

-

-

-

-
1930-31 R6, S6, SB6 .. .. .. .. .. .. .. .. .. ..

-

AMCS2

-

-

-

-

-

-
1932 T6, TB6 .. .. .. .. .. .. .. .. .. ..

-

AMCS1

-

-

-

-

-

-
1933-34 33-6, 34-6 .. .. .. .. .. .. .. .. .. ..

-

AMCS2

-

-

-

-

-

-
1935-36 .. .. .. .. .. .. .. .. .. ..

WHT

AMCLC

K2

SE1

-

-

-

-
1937-39 .. .. .. .. .. .. .. .. .. ..

WHT

AMC5

K3

SE1

-

-

-

-
1940-53 16M .. .. .. .. .. .. .. .. .. ..

WHT

AMC6

K3

SE1

-

-

-

-
1940-51 16MS, 16MC .. .. .. ... ..

WHT

AMC6

K3

SE1

LS10

LS10

STD650
1952-53 16MS, 16MC,16MCS

WHT

AMC6

K3

SE1

LS10

LS10

017489
1954 16MS, 16MC,16MCS

WHT

AMC6

K3

SE1

LS10

LS10

021481
1955-63 16MS, 16MC,16MCT

WHT

AMC6

K3

SE1

MS10

LS10

021962
1955 16MCS.. .. .. .. .. .. .. .. .. ..

WHT

AMC6

K3

SE1

MS10

LS10

021962
1956-59 16MCS.. .. .. .. .. .. .. .. .. ..

WHT

AMC12

K51

SE1

MS10

LS10

§
1948-55 7R (Racing) .. .. .. .. .. .. .. .. .. ..

Polished

AMC7R

K46

§

§

MS11
1956-63 7R (Racing) .. .. .. .. .. .. .. .. .. ..

Polished

AMC12L

K51

SE209

§

MS11
1960 8 (Light 350) .. .. .. .. .. .. .. .. ..

44023

AMC17

K51

SE143

LS9

LS9

042239
1961-63 8 (Light 350) .. .. .. .. .. .. .. .. ..

44023

AMC17

K51

SE143

MS10

RLS9
1964-66 16, 16C .. .. .. .. .. .. .. .. ..

-

AMC20

K51

SE1

MS10

LS10

RL10L

030184

Big End Catalogue

AJS 500cc models

AJS 500cc+ Twins