lubrication
engine bearing surfaces lubricated from a petrol/oil mixture in a 25:1 (4 per cent) ratio. Gearbox and primary drive shafts run in oil bath which also feeds main bearings.

engine
bore 55 mm
stroke 52 mm
cacity 123 cm
number of cylinders 1
compression ratio 10 ± 5:1
maximum power output 12 bhp at 7000 rpm
maximum torque output 9.1 lb. ft. at 6700 rpm
ignition timing (fixed) 2.5-2.9 mm btdc
cb gap setting .40-.48 mm
sparkplug Champion N3
thread size 14 mm X 3/4 in. reach
porting piston controlled
fitted ring gap .008-.012 in.
NB—bore is chromed and the piston must be matched to a particular barrel. Letters are stamped on the top fin of the barrel and on the piston crown to facilitate matching.

crankshaft

the crank and flywheels are pressed together and are only available as an assembly, complete with conrod.

big-end roller bearing
driveside main ball bearing
timing side main roller bearing
crankshaft endfloat zero
(the shaft is pulled up to the driveside main bearing)

fuel system
 
carburettor Bing 2/26/64
nominal bore 24 mm
main jet needle jet 1208 120
needle position 3rd notch from top
pilot jet 30
idling air screw 1.5 turns open
1968 Puch M125 1968 Puch M125 right side 1968 Puch M125 1968 Puch M125
The Puch M125 was sold in Canada and the USA under the Allstate brand. Similar to Vespa and Gileral products.

Produced in Austria, the M125 was reknowned for its robust motor and general reliability. After producing a line of split-singles since the 1920s, the M125 was the first “conventional” two-stroke produced by Steyer-Puch and was quickly adopted for trials work, especially ISDT-type competition. Interestingly, the cylinder is chrome plated.

For racing the displacement was increased to 175cc and six-speed gearbox was used.
Motorcycle Mechanics Magazine Cover : 1968M125 cutaway engineMotorcyle Mechanics Magazine Cover : 1970