Big end catalogue home page
J.A.P.
The range of J.A.P. engines is vast and only the most popular models are listed below. All J.A.P. big ends are available and many more are listed in the bearing configuration tables. These tables are only available to the public upon request from the factory.
80cc
Year |
Model |
Con rod casting No. |
Big end Part No. |
Cage Part No |
Small end Part No. |
MAIN BEARINGS |
|||
Drive Side |
Timing Side |
||||||||
–– |
Numerous power tools | –– |
JAP80 |
- |
- |
- |
- |
||
250cc
Year |
Model |
Con rod casting No. |
Big end Part No. |
Cage Part No |
Small end Part No. |
MAIN BEARINGS |
|||
Drive Side |
Timing Side |
||||||||
–– |
O.H.V. models | –– |
–– |
–– |
–– |
–– |
–– |
||
| 1934 | PO-Z | 7464/1 |
JAP1/A |
K17 |
SE41 |
–– |
–– |
||
| 1934 | PO-Z | 7464/1 |
JAP1/A |
K17 |
SE41 |
–– |
–– |
||
| 1935-37 | PO-Z | 7464/2 |
JAP1/B |
K18 |
SE41 |
–– |
–– |
||
| 1936-39 | PO-O, PO-F, OK Supreme | 7464/4 |
JAP1/C |
K19 |
SE41 |
–– |
–– |
||
350cc
Year |
Model |
Con rod casting No. |
Big end Part No. |
Cage Part No |
Small end Part No. |
MAIN BEARINGS |
|||
Drive Side |
Timing Side |
||||||||
–– |
O.H.V. models | –– |
–– |
–– |
–– |
–– |
–– |
||
| 1937 | GH & OK Supreme | 9314 |
JAP2/A |
K20 |
SE41 |
–– |
–– |
||
| All Years | Speedway | Alloy |
JAP4 |
K22 |
SE44 |
–– |
–– |
||
500cc
Year |
Model |
Con rod casting No. |
Big end Part No. |
Cage Part No |
Small end Part No. |
MAIN BEARINGS |
|||
Drive Side |
Timing Side |
||||||||
–– |
O.H.V. models | –– |
–– |
–– |
–– |
–– |
–– |
||
| 1932-37 | KO-Z | 8522 |
JAP3/A |
K20 |
SE42 |
–– |
–– |
||
| 1938-39 | KO-Z | S378M |
JAP3/A |
K20 |
SE42 |
–– |
–– |
||
| 1936 | KO-Z | 8522/1 |
JAP3/B |
K21 |
SE42 |
–– |
–– |
||
| All Years | Speedway (Alloy Rod) | Alloy |
JAP4 |
K22 |
SE44 |
–– |
–– |
||
| All Years | Speedway (Steel Rod) | Steel |
JAP4 |
K22 |
w |
–– |
–– |
||
600cc
Year |
Model |
Con rod casting No. |
Big end Part No. |
Cage Part No |
Small end Part No. |
MAIN BEARINGS |
|||
Drive Side |
Timing Side |
||||||||
| All years | Industrial | JAP3/A |
K20 |
SE42 |
§ |
§ |
|||
1000 & 1100cc
Year |
Model |
Con rod casting No. |
Big end Part No. |
Cage Part No |
Small end Part No. |
MAIN BEARINGS |
|||
Drive Side |
Timing Side |
||||||||
| 1936-40 | 980cc & 1100cc Twin | –– |
JAP5 |
–– |
§ |
§ |
§ |
||
| 1945-61 | 1100cc Racing Twin | Polished |
JAP11 |
K76 |
SE188 |
LS12 |
RLS12 |
||
The table below shows some of the piston data and perhaps more interestingly gudgeon pin sizes for most of the JAP machines. In keeping with JAP machines there are many choices between similar models.
| Model | Material | Bore |
Ref. No. |
Height |
Length |
Head Form |
Pin Ø |
| 288cc Model 4/3 | 70mm |
13105 |
19/32" |
215/32" |
Flat | 15.58mm |
|
| 500 Speedway | 80mm |
18547/HR |
147/64" |
37/64" |
Radius | 13/16" |
|
| 500 OHV | Heplex | 33/8" |
7160 |
113/16" |
3½" |
Radius | 13/16" |
| Model 6 588 SV | 33/8" |
9860 |
127/32" |
315/32" |
Flat – Bevel | 13/16" |
|
| 600 SV | Heplex | 33/8" |
S5891 |
1½" |
3½" |
Flat | 13/16" |
| 680 SV | Heplex | 2¾" |
929 |
15/8" |
227/32" |
Flat | 15.62mm |
| 680 OHV | Alloy | 70mm |
3409 |
15/16" |
231/64" |
Flat | 15.62mm |
| 980 SV | Alloy | 33/8" |
S7306 |
121/32" |
33/16" |
Flat | 13/16" |
| 980 SV | Heplex | 33/8" |
3332 |
15/8" |
3¼" |
Flat | 15.62mm |
| 980 SV Sports | Heplex | 33/8" |
1939 |
15/8" |
3¼" |
Flat – Bevel | 13/16" |
| 990 SV (Side by Side) | Alloy | 33/8" |
S7963 |
113/16" |
3½" |
Flat – Bevel | 7/8" |
| 990 SV "X" | Alloy | 33/8" |
S7333 |
113/16" |
3½" |
Flat – Bevel | 7/8" |
| 1100 OHV | Alloy | 33/8" |
3395 |
17/8" |
3½" |
Radius | 13/16" |
| 1100 OHV | Alloy | 33/8" |
3331 |
17/8" |
3½" |
Radius | 13/16" |