Royal Enfield 500 TWIN 1949 Workshop Maintenance Manual page 6

ROYAL ENFIELD WORKSHOP MANUAL
Cubic Capacity ... ...... ... ...... ... ......... 496 c.c.
Stroke ................. ... ................. .. ........ 77 m.m.
Bore ......... ... ...... ... .. Nominal
Actual
(Rebore to .020 in. when wear exceeds .005 in.
and again to .040 in. after further .005 in. wear).
Compression Ratio ...
Piston Diameter-
Bottom of Skirt-Fore and Aft. 63.830 m.m.
Top Lands .. 63.50/63.45 m.m.
Skirt is tapered and oval-turned.
Piston Rings
Width-Plain Rings ................ ...
Scraper Ring ......................... ...
Radial Thickness .................. 2.460/2.612 m.m.
Gap when in unworn Cylinder .011 / .015 in.
Clearance in grooves
Various oversize Pistons and Rings available.
Piston Boss Internal Diameter
Gudgeon Pin Diameter
ConRod Small End Internal Diameter .7507/.7505 in.
Big End Internal Diameter ........... 1.8535/1.8530 in.
Bearing Shell Internal Diameter ...1.7515/1.7505in.
Crank Pin Diameter ............... ... .. 1.7500/1.7495 in.
Driving Side Main Ball Bearing
Type ............ ... ..... ... ...... ... ....... S.K.F.6209
Outside Diameter ... ...... ... ......... 85 m.m.
Inside Diameter
Width ........... ... ..... ... ...... ... ......... 19 m.m.
Timing Side Main Roller Bearing-
Type ............ ... ..... ... ...... ... ...... S.K.F. N209
Outside Diameter .. ... ...... ... ......... 85 m.m.
Inside Diameter .... ... ...... ... ......... 45 m.m.
Width ........... ... ..... ... ...... ... ......... 19 m.m.
Rocker Inside Diameter ... ...... ... .5627/.5622 in.
Rocker Bearing Inside Diameter .5622/.5617 in.
Rocker Spindle Diameter ...... ... .5617/.5615 in.
Inlet Valve Stem Diameter
Exhaust Valve Stem Diameter
Valve Guide Internal Diameter
Valve Guide External Diameter
Valve Guide Hole in Cylinder Head Dia. .625/.626 in.
Tappet Stem Diameter ........... ... .3743/.3740 in.
Tappet Guide Internal Diameter
Tappet Guide External Diameter 1.0125/1.0130 in.
Tappet Guide Hole in Crankcase Dia 1.011/1.010 in.
Tappet Clearance with cold engine:
Inlet .............. ... ..... ... ...... ... ............. Nil
Exhaust ................. ... ....................... Nil
SECTION Alb
Technical Data
"500 Twin " Engine
64 m.m.
63.969 m.m.
7.1/2 to 1
.0615/.0625 in.
.1552/.1562 in.
.0005/ .0025 in.
.7500/.7498 in.
.7450/.7498 in.
... ...... ... ......... 45 m.m.
.3430/.3425 in.
.3410/.3405 in.
.3437/.3447 in.
.6275/.6270 in.
.3755/.3745 in.
Valve Spring Free Length
Inner ............ ... ...... ... ............... 2.1/32 in.
Outer ......................................... 2.3/32 in.
(Renew when reduced by 3/16 in.)
Valve Timing with .012 in. clearance--
Exhaust Opens
Exhaust Closes
Inlet Opens ...
Inlet Closes ...
Camshaft Bearing External Diameter .9095/.9085 in.
Camshaft Bearing Internal Diameter .7505/.7495 in.
(Bored in position in crankcase)
Cam Lift ............ ... ...... ... ..... ...
Valve Lift (approx.)
Timing Sprocket .......... ... ..... ... ...... 12 Teeth
Camshaft Sprocket ...... ... ..... ... ...... 24 Teeth
Magneto Sprocket ........ ... ..... ......... 19 Teeth
Timing Chain-Type
Length
Width
Pitch
Roller
Magneto Chain-Type
Length ........ ... ... 44 pitches
Width ... ..... ... ... 8.64 m.m.
Pitch ... ..... ... ... 8 m.m.
Roller ... ..... ... ... 5 m.m.
Magneto Speed ... ...... ... ..... Half Engine Speed
Points ... ...... ... .....
Timing Advanced 5/16 in.-3/8 in. before T.D.C.
For Coil Ignition see Section C1.page 2.
Engine Sprocket ........... ... ...... ... ...
Clutch Sprocket ........... ......... ... ...
Final Drive Sprocket (Solo) ... ...... ... 18 Teeth
Primary Chain Type
Length ......... ... ...... ... ...... ... ..
Width .......... ... ...... ... ...... ...
Pitch ............ ... ...... ... ...... ....
Roller .......... ... ...... ... ...... ...
Feed Oil Pump-Speed
Piston Diameter
Stroke
Return Oil Pump-Speed
Piston Diameter
Stroke ... ...
Sparking Plug. Type
Diameter
... ... 75° before B.D.C.
... 35° after T.D.C.
... ... 30° before T.D.C.
... ... 60° after B.D.C.
.3123 in.
... ..... ... .3125 in.
Single No. 110038 endless
... ..... ... ... 66 pitches
... ..... ... .225 in.
... ..... ... .375 in.
... ..... ... .250 in.
Duplex No. 114500 endless
.012/.015 in.
25 Teeth
56 Teeth
Duplex No. 114038 endless
90 pitches
.628 in.
.375 in.
.250 in.
.. ....... ... . 1/6 Engine Speed
.25 in. (nominal)
... ... .5 in.
1/6 Engine Speed.
.375 in. (nominal)
.5 in.
...Lodge CS14 K.L.G. F.50
Champion L10
14 m.m.