Complex sentence: Beneath the bonnet however, Villiers had substantially upgraded the 197cc engine, which now became the Mark 9E, this incorporated a 4-plate clutch, a heavier final drive chain with simplified adjustment and a higher top-gear ratio.
Split into simpler sentences: Beneath the bonnet however, Villiers had substantially upgraded the engine, which now became the Mark 9E. This incorporated a 4-plate clutch, a heavier final drive chain with simplified adjustment and a higher top-gear ratio.