Triumph “C” Range Unit Twin Bore & Stroke Data

Note

Type

Size,
CC

Bore,
MM

Bore,
Inches

Stroke,
MM

Stroke,
Inches

Rod,
Inches

Rod,
MM

Rod
Ratio

4K
P-speed

1  

3TA

349

58.25

2.579

65.5

2.579

5.311

134.9

2.055-1

9,306

2  

5TA

490

69     

2.717

3  

Big bore 1

519

71     

2.795

4  

Big bore 2

530

71.76

2.825

“C” Range ID:
  1.  1957-68 3TA, T90 unit construction 350 (not pre-unit 3T)
  2.  1958-74 5TA, T100A, T100C, T100R, T100SS, T100T, TR5T unit construction 500 (not pre-unit 5T, T100)
  3.  500 bored to 650 std. piston
  4.  “Big bore” cylinder, actually a 650 +.030” piston in the original 500 cylinder Random notes, in stream of conciousness order: