Barr & Stroud Sleeve Valve Engine 1921

The 350 c.c. B. and S. engine with oil base and cylinder head removed. On the left will be seen the ribbed aluminium base, and on the right the sunk cylinder head with single piston ring. Crank-shaft, piston, and connecting rod may be removed from the machine through the base without detaching the engine from the frame.

Credit: The MotorCycle