TECHNICAL SPECIFICATIONS
All Technical data from the service guide AMC Heavy weight singles. Published by Bruce Main-Smith LTD
| Bore, mm | 82.5 |
| Stroke, mm | 93 |
| Capacity, cc | 498 |
| Compression ratio | 6.0 |
| Valve Timing | All models use 0.016in tappet clearance |
| Inlet opens B.T.D.C. | 32 degrees |
| Inlet closes A.B.D.C. | 63 degrees |
| Exhaust opens B.B.D.C. | 65 degrees |
| Exhaust closes A.T.D.C. | 30 degrees |
| Ignition before T.D.C. full advance | 1/2 |
| Tappet clearance, engine cold | All models nil clearance |
| Carburetter, bore size | 1 3/32 |
| Main jet | 180 |
| Slide | 29/4 |
| Needle position | 2 |
| Needle jet | 29.076 |
| Needle | 29 |
| Cylinder size | 3.250in tolerance +0.0005 / -0.0005 |
| K.L.G. sparking plug | F80 iron head FE80 alloy head |
| Magneto contact gap | 0.012in |
| Alternator gap | 0.019 - 0.016 |
| Gearbox lubricant | 1 pint engine oil |
| Petrol tank capacity | 24 pints |
| Petrol tank reserve | 4 pints |
| Oil tank capacity | 4 pints |
| Top of skirt piston diameter | 3.2490in |
| Bottom of skirt piston diameter | 3.2494in |
| Gudgeon pin size | 7/8 -0.0010 \ -0.0013 |
| Connecting rod length (centres) | 6 3/8 |
| Timing side shaft diameter | 1.2275 \ 1.2300 |
| Rocker axle bush | 5/8: +0.00075 \-0.00050 |
| Camshaft bush | 1/2: +0.0005 \-0.0005 |
| Rocker axle sleeve | High limit 0.6235: Low limit 0.6230 |
| Camshaft axle | 3/8: -0.00125 \ -0.00175 |
| Small end bush | 7/8: +0.00050 \ -0.00025 |
| Flywheel end float
Flywheel diameter |
0.025 max
7 3/4 x 1.156in |
| Balance factor | 65% |
| Total rotating weight | 843.3gm |
| Reciprocating weight | 673.2gm |
| Balance weight | 1lb. 4oz.8 1/4gm 1 flywheel |
All Technical data from the service guide AMC Heavy weight singles.
Published by Bruce Main-Smith LTD
| Exhaust pipe | Best length open 48in |
| Wheel base | 54in |
| Head angle | 63 1/4 degrees |
| Trail | 2 5/8 |
| Valve spring free length narrow | 3 1/8in |
| Valve spring free length wide | 2in |
| Valve lift | 5/16in |
| Valve seat angle | 45 degrees |
| Push rod overall length | 9 5/32 |
| Valve guide protrusion (inlet & exhaust) | 1/2in |
| Valve stem diameter inlet | 0.3730 high limit & 0.3720 low limit |
| Valve stem diameter exhaust | 0.3715 high limit & 0.3705 low limit |
| Crank pin diameter | 1.20375 high limit & 1.20350 low limit |
| Crankpin rollers | 0.250 x 0.0250 (30 off) |
| Connecting rod sleeve diameter | 1.70400 high limit & 1.70375 low limit |
| Timing side bush | 1.125 / 1.255 |
| Driving side bush | 1.0002 high limit & 0.9997 low limit |
| Engine sprocket | 1st | 2nd | 3rd | top | internal ratios |
| 15 teeth | 18.69 | 12.32 | 8.96 | 7.0 | |
| 16 teeth | 17.5 | 11.54 | 8.39 | 6.56 | 1st 2.67 |
| 17 teeth | 16.44 | 10.48 | 7.88 | 6.16 | 2nd 1.76 |
| *18 teeth | 15.57 | 10.26 | 7.47 | 5.83 | 3rd 1.28 |
| 19 teeth | 14.6 | 9.6 | 7.0 | 5.49 | top 1-1 |
| 20 teeth | 14.01 | 9.24 | 6.72 | 5.25 | |
| #21 teeth | 13.35 | 8.8 | 6.4 | 5.0 |
TYRES
| Front | 3.25 x 19 |
| Rear | 3.50 x 19 |
| Magneto | Lucas N1 chain driven |
| Dynamo | Lucas E3N |
| Regulator | Lucas cvc MCR2 |
| Horn | Lucas HF1234 |
| Battery | 6 Volt Lead acid |
| System | Positive to Earth |
this means
BLACK-Frames, Forks, Hubs, Oil tank, Toolbox, Chaincase, Chainguard, Headlamp shell and other painted items.
CHROME-Exhaust, Handlebars, Controls, Pushrod tubes, Fork caps Fork oil seal holders, Petrol cap, Oil cap,Headlight rim and Wheel rims (export Model).
ARGENISED-Wheel rims (Domestic model). NB: Powder coating with a silver/grey matt finish has given a fairly realistic finish on the wheel rims, according to a post in the Jampot forums.
POLISHED ALUMINIUM-Lower fork legs and Brake back pads.
PETROL TANK-Black with lining in gold paint, Die cast AJS Badges
and Moulded knee rubbers(domestic model). Or Chrome plated with wide black
panels, Die cast AJS Badges and Moulded knee rubbers (export model)
For more information on this page visit Emu Archives
If you have a query or information about AJS motorcycles please contact us
