GB568799A - Improvements in or relating to motorcycles - Google Patents

Abstract

568,799. Driving-gear ; crank-chambers. COVENTRY-EAGLE CYCLE & MOTOR CO., Ltd., and WOODMAN, A. C, May 8, 1943, No. 7315. [Class 7 (ii)] [Also in Group XXXI] A power and changespeed unit for motor cycles having the primary and secondary drives at opposite sides of the changespeed gear with the kickstarter spindle mounted separately from the primary gear-shaft, is characterised in that the. engine is of the two-stroke type with a built-up crankcase and the change-speed gear is controlled by means of a foot lever 26 mounted on a forwardlyextended longitudinal shaft 27 carrying the gear - operating forks. In the construction shown, the engine is of the two-cylinder, twostroke type with the cylinders 2 horizontal and the cylinder-head 3 at the forward end. In order to prevent distortion of the common cylinder wall 4, the induction ports 5 and two of the four transfer ports 6 are formed therein. The carburetter 7 is carried by the cylinderhead and is connected by a passage 8 with the induction ports 5. The crank-case is formed in three sections having paralleljoints containing the cylinder axes, (1) one outer section 12 is extended rearwardly to form one end of the gear-box 13 and carries a cover 14 enclosing the primary drive 15 and clutch 16 ; (2) the other outer section 17 is extended laterally to form a casing 18 for the fly-wheel 19 and dynamo 20 and has a support bracket 21 for the other end of the gear-box 13 ; and (3) the middle section 22 is itself divided in a plane parallel to the crank-shaft 11. The changespeed gear is at the rear of the engine and comprises a main-shaft 23 and a lay-shaft 24 (not shown) preferably above it. The clutch 16 and primary drive 15, from the engine are at one side and the final or secondary drive 25 at the other side of the cycle. The gear is controlled by a longitudinal rocking-shaft 27 having the gear lever 26 at its forward end, the gear control being preferably of the onestep type with the gear lever returned automatically to its normal position after each gear-change. The spindle 30 of the kickstarter is mounted independently of the gearshafts 23, 24 and its toothed sector 31 engages a pinion 32 on the main-shaft 23. The unit, when installed on the cycle, may be completely enclosed, except for the gear lever 26 and the kick-starter crank, in a housing in the cycle frame such as that described in Specification 560,328.