Inclined OHV Engine
Engine. 4.93 h.p., 80 x 98 m/m bore and stroke with two-port head. Enclosed roller bearing rockers. Enclosed push rods, adjustable return springs. Double row roller big end bearing, pressure oil fed. Low compression piston standard. High compression piston can be fitted if specified. Two spare valve springs supplied.
Silencers. Two well-proportioned silencers with fish tails, mounted securely on either side of the machine.
Carburetter. Amac T.T. Twist grip control to throttle if specified.
Lubrication. Oil sump integral with crank ease. Capacity 3 pints. Sub- merged gear pump, visible tell-tale. Surplus oil in crank case returned to sump by scraper acting on flywheels. Oil level gauge. Additional oil tank on seat tube extra.
Transmission. Front chain, ½in.× .305in., enclosed in two-part case. Rear chain, 5/8in.× 3/8in., efficiently protected. Cam-faced cush drive fitted to engine shaft.
Gear Box. Special pivot mounting. A special close or wide ratio gear box can be fitted if specified.
Frame. Duplex cradle frame. Head fitted with B.S.A. steering damper. Detachable carrier extra. Spring up rear stand.
Handlebar. Sporting type (reversible), mounted behind steering head, with long rubber grips.
Tank. Saddle type for fuel only, nickel-plated, with top panel in B.S.A. green. Capacity: gallons. Adjustable rubber knee grips fitted.
Tyres. Dunlop cord, 26in.× 3.25in., W.O., 26in.× 3in. W.O. tyres can be fitted if specified. 27in.× 4in. Balloon tyres, with special front mudguard extra.
Brakes. 7in. diameter, taper roller bearings to both hubs. Rear brake quickly adjustable.
Saddle. Spring seat, de luxe type.
This machine can fitted with a specially-tuned engine (high compression piston) and supplied with spare piston (low compression), complete with rings and gudgeon pin, spare racing plug, valve, valve springs and engine sprocket at an extra charge of £6.
In addition to the road-going S29 twin-port, the factory produced some 400 speedway bikes using this engine, many of which were exported to Australia. See 1929 S29 DT Speedway