The Solifer SM was one of the best-known mopeds of the Finnish maker Solifer. It was introduced in 1974 and remained in production until 1986, changing gradually from the so-called fat-tank model to the slim-tank generation and gaining an automatic version along the way.
Solifer SM at a glance
| Maker | Solifer, Finland |
|---|---|
| Production | 1974–1986 |
| Class | light moped |
| Engine | Tomos 50/4-K, 48.8 cm³ two-stroke |
| Power | 1.1 kW at 4,000 rpm |
| Torque | 3.12 Nm at 3,000 rpm |
| Gearbox | four-speed as standard, fifth gear available |
| Fuel tank | 5.5 litres in 1974–76, 4.5 litres later |
| Tyres | 2.75 x 17 front and rear |
| Automatic version | SMA, 1976–1979 |
The SM is described in detail only in the Finnish Wikipedia; the English article covers the company.
History of the Solifer SM
Fat tank and slim tank
The SM appeared in 1974 with a larger fuel tank, frame, saddle, headlight and instrument panel than the models that followed. This first generation is known in Finland as the “fat tank” (läskitankki). Its engine had a small-finned cylinder with small transfer ports, and the exhaust flange was smaller than on the later type. In 1976 a two-speed automatic version, the SMA, joined the range, and in 1977 came the first “slim tank” (luikkutankki) machines. These had a large-finned cylinder and larger transfer ports in the crankcases as well, the exhaust ran at the side, the rear mudguard mounts rose upwards and the saddle was fixed outside the frame next to the shock absorbers. The fork lower tubes were chromed from 1977 to 1980 and painted from 1981.
The 1982 revision
From 1982 to 1986 the SM used a cradle-tube frame with the exhaust running through the middle of the frame. That made the tool box noticeably smaller and moved the saddle’s rear mounting onto the centre tube. The hubs changed from Maillard to Grimeca, the fork lower tubes were painted and the extra crankcase chamber was dropped. Around 1982 the crankshaft bearings also changed from the old adjustable L17 type to standard 6203 C3 ball bearings, which are wider, so the two types cannot simply be swapped.
The Tomos engine
The SM used the Tomos 50/4-K engine, a two-stroke of 48.8 cm³ with a 38 mm bore and 43 mm stroke and a compression ratio of 7.0:1. It produced 1.1 kW at 4,000 rpm and 3.12 Nm at 3,000 rpm, fed by a Bing 1-11-49 carburettor of 11 mm. The small-finned cylinder of 1974–76 was replaced in 1977 by a larger-finned one because the early type overheated easily on the hottest summer days; the newer cylinder also had bigger transfer ports. Between about 1977 and 1981 the engines had an extra chamber joined to the crankcase by two drilled holes, which lowered crankcase pressure and slightly reduced power. The Tomos gearbox originally had five gears, but the highest was removed to keep the moped within the 40 km/h limit of the time, either by the importer or at the factory by fitting bushes in place of the gears. The missing gear can be added again, and a five-speed Solifer runs at about 45 km/h.
Details and equipment
The exhaust of the 1974–81 models ran high past the saddle; from 1982 it passed under the tank and saddle so that the rider’s leg could not touch it. Fat-tank models had Maillard hubs with either 100 mm twin-spring or 90 mm single-spring brake shoes; Grimeca hubs with pressed-steel brake plates arrived in 1981. The fuel mixture was 4 per cent two-stroke oil, the electrical system was 6 volt with 18 W and 5 W outputs, and the spark plug was an NGK B7HS.
Design and features
- Two generations: the fat-tank SM of 1974–76 and the slim-tank models from 1977.
- Tomos two-stroke: a 48.8 cm³ engine with a four-speed gearbox and an optional fifth gear.
- Automatic SMA: a two-speed automatic version sold from 1976 to 1979.
- Gradual updates: new frame, exhaust routing, hubs and bearings arrived during the 1980s.
- Long life: twelve years in production, from 1974 to 1986.
Solifer SM versions
- SM 1974–1976: the fat-tank model with a small-finned cylinder.
- SMA 1976–1979: two-speed automatic with a Tomos A32-KS engine and Encarwi S85 carburettor.
- SM 1977–1981: slim-tank models with a large-finned cylinder and an extra crankcase chamber.
- SM 1982–1986: cradle frame, central exhaust, Grimeca hubs and 6203 C3 bearings.
The SM sat alongside the older Solifer Export in the range, and its automatic version is described with the Solifer Automat models. More Finnish mopeds are in the Solifer collection.
Video: Solifer sm sounds
Video by JomberoHD on YouTube.
Sources
- Solifer SM, Finnish Wikipedia: model history, versions, engine, technical data
- Solifer, Finnish Wikipedia: company history, model list
- Solifer, English Wikipedia: company history, moped production
