Complex sentence: Both Nortons and the T160 were improved by the fitting of an electric starter, a left side gear change, right foot brake and rear disk brake; the Bonneville got its own electric start in 1980 when marketed by the Meriden worker's co-operative itself.
Split into simpler sentences: Both Nortons and the T160 were improved by the fitting of an electric starter, a rear disk brake and the left side gear change/right foot brake. The Bonneville got its own electric start in 1980 when marketed by the Meriden worker's co-operative itself.