Bore 88mm, stroke 82mm, capacity 499cc
Compression ratio 6.85:1
Output 26.2hp at 4,800 rpm
Torque 28ftlb at 3,700 rpm (but barely varies across the entire rev range)
Tappets (measure cold) In: 0.10mm 4 thou Ex: 0.20mm 8 thou
Oil - 3 litres. Use 20W/30 in Winter, 40W/50 in Summer, according to the manual. Or just use 20W/50 all year round. Measure the level with the dipstick out of its thread and placed on top of the hole.
Dell'Orto VHB 29 A
And to quote the manual:
Choke: 29mm diameter Slide: 60 Emulsion tube: 265 P Main jet: 132 (NB, Mick Walker's book says 122, and mine uses a 124) Pilot jet: 50 Needle: V 10 2* tacca Slow running adjustment: 1.25 turns out.
Points gap 0.42-0.48 mm 17-19 thou
Plug gap 0.6mm 24 thou
Plug NGK B8ES, B7ES or B6ES. 6 is the hottest.
Timing - fixed advance of 10 degrees. The centrifugal advance adds another 34 degrees, making a total maximum advance of 44 degrees. The centrifugal advance begins at 1200rpm and climbs in a straight line to achieve full advance at 3000 rpm. Graph
Forks - use 160ml in each leg of Agip ATF II D, or a 10W SAE engine oil. This is Agip's advice, based on the oil specified in the manual. It sounds like a standard 10W SAE fork oil should do the job.
18" rims. Use 3.50" section front and back, or a 3.25" on the front.
Pressures: front 23psi. rear 28psi solo, 34psi two-up.
Add 3psi front and back for 'fast running' (it says in the manual).
Michelin recommend pressures of 24 front and 28 rear, with their 3.50x18 M38s tyre.
If you are going to take anything apart, go out and buy the largest sizes of spanners and sockets you can find. Just measure a few of the bolt heads - you will find that you need sizes from 20mm upwards. Don't be tempted to use an adjustable spanner.
| Special tools | |
| Working on the valve gear | Easy job, as it sticks out the front. |
| Removing the engine flywheel | Oil seal change or replacement of the neutral switch. |
| Removing the timing-side engine cover | Clutch, camshaft, oil pump, primary gears |
| Working on the front forks | Another awkward job when you don't know how |
| Setting the ignition timing | Help, there's no timing mark! |
| Making a spacer to stop the chain grinding | Stops it eating the drive shaft and spring |
| Changing the kickstart spring | Without removing the flywheel |
There is an online guide to metal bashing here.
Teo Lamers, Agostinis and NLM sell the parts book and the workshop manual:
10-92-00-70 PARTS MANUAL 10-92-01-70 SERVICE MANUAL
The beginnings of an online parts list live here.