Trail Bronc

BSA Trail Bronc review from Hot Rod Magazine 1964

Kicking off our trail bike review is a real volume package by one of the oldest motorcycle manufacturing firms in the business: Birmingham Small Arms of England. Their newly announced "Trail Bronc" is big news on at least two special counts: this tried and proven 174cc (10 1/2 cubic inch) two-stroke single is over twice the capacity of the average 50 to 80cc trail bike with only a negligible 25 pounds or so additional overall weight (about 200 pounds fueled), and the price is right (within $20 of some of the smaller-engined jobs) at $395.
In order to give the buyer a healthy eight horsepower at this price, BSA has ignored the frills: No chrome (I take it back-the gas cap), no speedometer, front fender, or lights-their original assumption being that such items were costly, heavy, and unnecessary in this critter's natural habitat. Ignition is by a flywheel generator, however (no battery), and if lights are desired, lighting coils are in place for simple attachment to any sort of 6-volt accessory lamps.
Engine and integral 3-speed gearbox are genuine motorcycle components, this design having been refined through nearly a decade of highway and competition use-no guesswork here. The carburetor, too, is the reliable Amal brand with 7/8-inch venturi. Utter simplicity is the keyword of engine layout; two-stroke construction with 61.5mm bore, 58mm stroke, and 7:4 compression. With its huge 80-tooth rear wheel sprocket, this happy little powerplant is a veritable stump-puller at just above idle, even when the going gets deep and sticky, or it can buzz down the road at a neck-snappin' 40 mph. With the 1 3/4-gallon tank topped up with 20:1 gas-oil mix, it should provide all but the most "eager beavers" with a full day in the woods.