The Ural-3, model M-66, was the 1971 replacement for the M-63 and stayed in production until 1975. The engine was thoroughly revised: compression rose from 6.2 to 7 and power from 28 to 32 hp, the crankshaft was strengthened, and a full-flow paper oil filter was added to the lubrication system.
Ural M-66 at a glance
| Maker | Irbit Motorcycle Factory (IMZ), Irbit |
|---|---|
| Production | 1971–1975 |
| Also known as | Ural-3 |
| Predecessor | Ural-2 M-63 |
| Engine | 649 cc air-cooled boxer twin |
| Power | 32 hp, up from 28 hp |
| Compression | 7, up from 6.2 |
| Oil system | full-flow paper filter |
| Air filter | paper element |
| Front fork | tubes of larger diameter |
| Top speed | 105 km/h |
| Fuel consumption | 5.8 litres per 100 km |
No free photograph of a standard M-66 was found on Wikimedia Commons, so the previous cover of the entry is kept.
History of the Ural M-66
A stronger engine
The M-66 was the third generation of the 650 cc Ural. Power rose from 28 to 32 hp and compression from 6.2 to 7. The crankshaft was made more durable by strengthening the connecting-rod journal and the lower end of the connecting rod, and the lubrication system received a full-flow paper filter; the air cleaner was given a paper element as well.
The rest of the motorcycle
The front fork tubes were made from larger-diameter pipe, and a union nut with an asbestos cord sealed the joint between the exhaust pipe and the silencer. The frame, fork, fuel tank and handlebar were reshaped, and for the first time the motorcycle carried turn signals and new lights. The outfit reached 105 km/h, used 5.8 litres per 100 km and had 150 mm of ground clearance.
Design and features
- 32 hp: four more than the M-63, from higher compression and a revised engine.
- Full-flow paper oil filter: a first for the Ural, and a large step for engine life.
- Stronger crankshaft: reinforced connecting-rod journal and lower head.
- Turn signals: fitted as standard, with new lights.
- Bigger fork tubes: a stiffer front end on rough roads.
Ural M-66 versions
- Ural-3 M-66 (1971–1975): the standard sidecar outfit.
- Ural-3 with sidecar wheel drive: the military and utility versions of the same design.
The M-66 followed the M-63 and was replaced by the M-67; the whole family is covered on the Ural 650 page. More machines are in the Ural collection.
Video: Ural M-66 Flathead Bobber Startup
Video by Jürgen Jingelheimer on YouTube.
Sources
- Урал М-66, Russian Wikipedia: engine changes, dimensions, performance
- Урал (мотоцикл), Russian Wikipedia: place in the model range
- IMZ-Ural, English Wikipedia: factory history
