| Date | cc | Model | Note | Metal | Cyl Bore (mm) | Cyl Bore (in) | Ref No. | Veloce Part No. | Comp | Length | Bottom Skirt Diameter | Clearance - Inch | Weight | Head | No.Rings | Top Width | Ref.No or Radial Depth | Second Width | Ref.No or Radial Depth | Third / Oil RingWidth | Ref.No or Radial Depth | Ring Below Pin Width | Ref | Pin Dia | Pin Length | Type | Pin Ref No. |
| 1928/9 | 249 | U Offset inlet port 1 ¾” on Circumference at bottom of skirt | Cast Iron | 63.00 | 2.4803 | 8112 | 1 19/32 | 3 27/32 | Two Stroke | 2 | 1/8” | 0.091" | 1/8” | 0.091" | * | * | * | * | ½” | GP.8112 | |||||||
| 1929 | 249 | USS 48mm Offset Port 48mm at Bottom of Skirt | Al | 63.00 | 2.4803 | 3871 | 1 25/32” | 4 1/32” | Two Stroke | 2 | 3/32” | 0.091" | 3/32” | 0.091" | * | * | * | * | ½” | GP.3871 | |||||||
| 1930/1 | 249 | GTP inlet port 1 5/16” on circumference at bottom of skirt | Al | 63.00 | 2.4803 | 3867 | 1 ¾” | 4” | Two Stroke | 2 | 1/8” | 0.091" | 1/8” | 0.091" | * | * | * | * | ½” | GP.3867 | |||||||
| 1930/3 | 249 | GTP inlet port 1 ¾” on circumference at bottom of skirt | Al | 63.00 | 2.4803 | 3868 | 1 ¾” | 4” | Two Stroke | 2 | 1/8” | 0.091" | 1/8” | 0.091" | * | * | * | * | ½” | GP.3868 | |||||||
| 1934/40 | 249 | GTP inlet port 1 1/16” on circumference in middle of skirt | Al | 63.00 | 2.4803 | WP.1520 | 1 25/32 | 4 1/32 | Two stroke | 2 | 3/32” | 0.091" | 3/32” | 0.091" | * | * | * | * | ½” | 127E.11 | |||||||
| 1932/3 | 249 | GTP inlet port 1 5/16” on circumference at bottom of skirt | Al | 63.00 | 2.4803 | 3869 | 1 25/32 | 4 1/32 | Two stroke | 2 | 3/32” | 0.091" | 3/32” | 0.091" | * | * | * | * | ½” | GP.3869 | |||||||
| 249 | GTP offset inlet port 1 ¾” on circumference at bottom of skirt | Al | 63.00 | 2.4803 | 3872 | 1 25/32” | 4 1/32” | Two Stroke | 2 | 3/32” | 0.091" | 3/32” | 0.091" | * | * | * | * | ½” | GP.3872 | ||||||||
| 249 | GTP inlet port 1 13/16” on circumference in middle of skirt | Al | 63.00 | 2.4803 | 3873 | 1 25/32 | 4 1/32 | Two stroke | 2 | 3/32” | 0.091" | 3/32” | 0.091" | * | * | * | * | ½” | GP.3873 | ||||||||
| 249 | GTP | Al | 63.00 | 2.4803 | 3870 | 1 25/32 | 4 1/32 | Two stroke | 2 | 3/32” | 0.091" | 3/32” | 0.091" | * | * | * | * | ½” | GP.3870 | ||||||||
| 1934/49 | 248 | OHV | MOV /MAC Slipper Design | Al | 68.00 | 2.6772 | WP.357 | 1 9/16” | 3” | Dome (with valve pockets) | 3 | 1/16” | 0.098" | 1/16” | 0.098" | 5/32" | 0.098" | * | * | 5/8” | 158E.38 | ||||||
| 6.0 to 1 | * | * | |||||||||||||||||||||||||
| 1956 | 349 | OHV | Viper (Split skirt Alfin barrel) superseded by 2301-5 | Al (52) | 72.00 | 2.8346 | 2301-4 | M27-13 | 2.437” | 3.408” | 2.8347 | 0.000 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | |||
| 1956 | 349 | OHV | Viper (Split skirt Alfin barrel) | Al (52) | 72.00 | 2.8346 | 2301-5 | M27-13 | 2.437” | 3.408” | 2.8337 | 0.001 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | |||
| 349 | OHV | Viper Scrambles (Solid skirt Alfin barrel) superseded by 2301-? | Al (52) | 72.00 | 2.8346 | 2310-3 | M27-17 | 2.437” | 3.408” | 2.8335 | 0.001 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | ||||
| 349 | OHV | Viper Scrambles (Solid skirt Alfin barrel) | Al (52) | 72.00 | 2.8346 | 2310-? | M27-17 | 2.437” | 3.408” | 2.8315 | 0.003 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | ||||
| 1960 | 349 | OHV | Viper (Split skirt Iron barrel) Superseded by 2310-10 | Al (52) | 72.00 | 2.8346 | 2310-8 | M27-27 | 2.437” | 3.408” | 2.8327 | 0.002 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | |||
| 1960 | 349 | OHV | Viper (Split skirt Iron barrel) | Al (52) | 72.00 | 2.8346 | 2310-10 | M27-27 | 2.437” | 3.408” | 2.8315 | 0.003 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | |||
| 1960 | 349 | OHV | Viper / Scrambles (solid skirt Iron barrel) | Al (52) | 72.00 | 2.8346 | 2310-9 | M27- 24 | 2.437” | 3.408” | 2.8305 | 0.004 | Dome (with valve pockets) | 3 | 0.0625 | 0.115" | 0.0625 | 0.115" | 0.1575 | 0.115" | * | * | .8226” | 2.09E+05 | |||
| 348 | OHC | Al | 74.00 | 2.9134 | 3885 | 1 19/32” | 2 29/32” | Dome | 3 | 1/8” | 0.105" | 1/8" | 0.105" | 5/32" | 0.105" | * | * | 0.8236 | GP.3885 | ||||||||
| 348 | OHC | KTT CR 11.5 to 1 | Al | 74.00 | 2.9134 | 3883 | 2 3/32 | 3 7/16 | Dome | 3 | 1/16” | 0.106" | 1/16” | 0.106" | 5/32" | 0.106" | * | * | 0.8236 | GP3883 | |||||||
| 348 | OHC | Al | 74.00 | 2.9134 | 3884 | 1 3/4 | 3 1/16 | Flat Bevelled | 3 | 1/8” | 0.105" | 1/8" | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP.3884 | ||||||||
| 348 | OHC | Al | 74.00 | 2.9134 | 3888 | 1 7/8” | 3 3/16” | Dome | 2 | 1/16” | 0.105" | 1/16” | 0.105" | 0.105" | * | * | 5/8” | GP3888 | |||||||||
| 348 | OHC | Al | 74.00 | 2.9134 | 3887 | 1 31/32” | 3 9/32” | Dome | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP3887 | ||||||||
| 348 | OHC | Al | 74.00 | 2.9134 | 3886 | 1 13/16” | 3 1/8” | Cone | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP3886 | ||||||||
| 1929 | 348 | OHC | KTT CR 7 to 1 | Al | 74.00 | 2.9134 | 3875 | 1 27/32” | 3 7/32” | Dome | 3 | 1/16” | 0.106" | 1/16” | 0.106" | 5/32" | 0.106" | * | * | 0.8236 | GP.3875 | ||||||
| 1929 | 348 | OHC | KTT CR 8.5 to 1 | Al | 74.00 | 2.9134 | 3876 | 1 27/32” | 3 5/32” | Dome | 3 | 1/16” | 0.106" | 1/16” | 0.106" | 1/16” | 0.106" | * | * | 0.8236 | GP.3876 | ||||||
| 1929/30 | 348 | OHC | KTS, KSS 10.25 to 1 | Al | 74.00 | 2.9134 | 3877 | 2 1/8” | 3 7/32” | Cone | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 1/16” | 0.105" | * | * | 5/8” | GP.3877 | ||||||
| 1929/31 | 348 | OHC | KTP, KN | Al | 74.00 | 2.9134 | 3878 | 1 25/32” | 3 3/32” | Cone Stepped | 3 | 1/8” | 0.105" | 1/8" | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP.3878 | ||||||
| 1929/31 | 348 | OHC | KTT CR 10.25 to 1 | Al | 74.00 | 2.9134 | 3879 | 1 31/32” | 3 9/32” | Cone | 3 | 1/16” | 0.106" | 1/16” | 0.106" | 1/16” | 0.106" | * | * | 0.8236 | GP3879 | ||||||
| 1932/35 | 348 | OHC | KTS 6.5 to 1 | Al | 74.00 | 2.9134 | 3881 | 1 3/4 | 3 3/32 | Dome | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP.3881 | ||||||
| 1933 | 348 | OHC | KTT CR 7.75 to 1 | Al | 74.00 | 2.9134 | 3880 | 1 25/32 | 3 5/32 | Dome | 3 | 1/16” | 0.106" | 1/16” | 0.106" | 5/32" | 0.106" | * | * | 0.8236 | GP.3880 | ||||||
| 1936 | 348 | OHC | KTS 6.8 to 1 Slipper Design | Al | 74.00 | 2.9134 | 3882 | 1 13/16” | 3 1/8” | Dome | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP.3882 | ||||||
| 1936 | 348 | OHC | KSS MkII 6.8 to 1 Slipper Design | Al | 74.00 | 2.9134 | WP.1536 | 1 13/16 | 3 1/8 | Dome | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 5/32" | 0.105" | * | * | 5/8” | 158E.64 | ||||||
| 1936-47 | 348 | OHC | KSS Mk II Slipper Type 7.5 to 1 | Al | 74.00 | 2.9134 | 3874 | 1 29/32 | 3 7/32 | Dome | 3 | 1/16” | 0.105" | 1/16” | 0.105" | 5/32" | 0.105" | * | * | 5/8” | GP.3874 | ||||||
| 1935/47 | 495 | OHV | MSS CR 6 to 1 | Al | 81.00 | 3.189 | 3889 | 1 13/16 | 3 5/16 | Dome (with valve pockets) | 3 | 2mm | 0.116" | 2mm | 0.116" | 4mm | 0.116" | * | * | 0.8236 | GP.3889 | ||||||
| 1954 | 499 | OHV | MSS | Al (52) | 86.00 | 3.3858 | 1883 | 2.011 | 3.292 | Dome | 3 | 5/64” | 0.138" | 5/64” | 0.138" | 5/32" | 0.138" | * | * | 0.8236 | 2.09E+05 | ||||||
| 499 | OHV | MSS Split skirt Iron barrel | Al (52) | 86.00 | 3.3858 | 1883 -13 | M27-30 | 2.011 | 3.292 | 3.3838 | 0.002 | 15.00 oz | Dome | 3 | 5/64” | 0.138" | 5/64” | 0.138" | 5/32" | 0.138" | * | * | 0.8236 | 2.09E+05 | |||
| 1954/6 | 499 | OHV | MSS Scrambler / VM CR 8:1 | Al (52) | 86.00 | 3.3858 | 1883-07 | 2.369 | 3.65 | Dome (with valve pockets) | 3 | 5/64” | 0.138" | 5/64” | 0.138" | 5/32" | 0.138" | * | * | 0.8236 | 2.09E+05 | ||||||
| 1954/6 | 499 | OHV | MSS Scrambler / VM CR 9:1 | Al (52) | 86.00 | 3.3858 | 1883-08 | 2.422 | 3.703 | Dome (with valve pockets) | 3 | 5/64” | 0.138" | 5/64” | 0.138" | 5/32" | 0.138" | * | * | 0.8236 | 2.09E+05 | ||||||
| 499 | OHV | MSS Scrambler / VM CR 9:1 Split skirt Iron barrel | Al (52) | 86.00 | 3.3858 | 1883-14 | 2.422 | 3.703 | 3.3838 | 0.002 | 14.75 oz | Dome (with valve pockets) | 3 | 5/64” | 0.138" | 5/64” | 0.138" | 5/32" | 0.138" | * | * | 0.8236 | 2.09E+05 |