JA Purity IV JA Purity IV
JA Purity IV JA Purity IV
  • About The Site
  • Blue Book
  • Public Velo Stuff
  1. You are here:  
  2. Home
  3. Velocette Documents
  4. Venom, Viper, MSS
  5. F485/1R Owner's Handbook 1956
  6. Useful Data

ENGINE

  Viper. Venom and MSS.
Bore 72 mm. 2.8347-in. 86 mm. 3.385-in.
Stroke 86 mm. 3.385-in. 86 mm. 3.385-in.
Capacity(swept vol.) 349 c.c. 21.29 c. in. 499 c.c. 30.45 c. in.
Rated Horse-power (A.C.U. Rating) 3.5 5
†Running tappet clearances: .005-in. .005 -in.

 

 Engine serial number and prefix stamped on left hand side of crankcase just below cylinder base flange. See page 34.

GEARBOXES

 Overall ratios with standard driving sprocket on gearbox : *

  Viper Venom MSS
1st 12.6 to 1 11.2 to 1 12.4 to 1
2nd 8.73 to 1 7.74 to 1 8.57 to 1
3rd 6.64 to 1 5.88 to 1 6.52 to 1
Top 5.5 to 1 4.87 to 1 4.87 to 1

 Gearbox serial prefix and number stamped on top of housing on right hand side.

TANK CAPACITIES

Fuel 3 Imperial Gallons; 13.6 litres; or 3.6 U.S. Gallons
Oil ½ Imperial Gallon; 2.27 litres; or 0.6 U.S. Gallons 

TRANSMISSION

  Viper Venom and MSS
Engine Sprocket 21T 23T
Clutch Sprocket 44T 44T
Gearbox Sprocket 21T 18T*
Rear Wheel Sprocket 55T 46T
Primary Chain .5 x .305-in. 67 P 
Roller dia. .335-in.
.5 x .305-in. 68 P *
Roller dia. .335-in.
Rear Chain  .5 x .305-in. 124 P
Roller dia. .335-in.
.625 x 380-in. 101 P
Roller dia. .335-in.

WHEELS & TYRES

  Viper Venom MSS
Front Rim WM2 x 19 WM2 x 19 WM2 x 19
Rear Rim WM2 x 19 WM2 x 19 WM2 x 19
Front Tyre 3.25 x 19-in Rib 3.25 x 19-in Rib 3.25 x 19-in Stud
Rear Tyre 3.25 x 19-in Stud 3.25 x 19-in Stud 3.25 x 19-in Stud

FRAME

Serial number and prefix stamped on right-hand side of front seat lug

†These are running clearance set cold. Different clearances must be employed for checking valve timing. See page 40 before checking or adjusting.

Always quote the engine serial number and prefix on all orders for spare parts and in any correspondence with the factory.

 *A smaller sprocket and shorter chain are used if a sidecar is fitted.

Previous article: Legal Formalities To Be Observed Prev Next article: The Controls Next
Open menu
  • Velocette Documents
    • GTP Manuals
      • F40/5R GTP Instruction Book 1951
    • KSS, KTS Manuals
      • F236/4R Mk. II OHC Instruction Book 1950
      • F42/3R OHC Models 1925-1931 Instruction Book
    • MAC Manuals
      • F469/4R MAC Service Guide 1965
      • F466/2R MAC Owner's Handbook 1955
      • F50/7R MAC Rigid Frame Service Manual 1955
      • F50/4R Supplement
    • MOV and MAC
      • F131-3R Instruction Book 1937
    • MSS Manuals
      • F477 Owners Handbook 1954
    • Venom, Viper, MSS
      • F485/1R Owner's Handbook 1956
      • F484/9R Service Guide 1967
      • F484/11R Service Guide 1971
    • Valiant Manuals
      • F62-1R Service Manual