With the new bearings, piston rings and seals fitted into the 850 block (at last), it was time to pull the old 700cc engine from the Vegemite Special so certain other parts could be swapped over. Firs

…from a world champion mechanic. Yamaha spanner ace Liam Coffey reveals all

Engineering expert and creator of brilliantly bonkers bikes in MCN every month

Part FOUR: Rob Hawkins and CM editor Martyn Knowles deliver the Aygo’s original engine to Harrogate College and follow the students stripping it down to discover why it was so smoky.

Big, air-cooled retro is now an affordable, exciting modern classic

Pinning down the cause of the recurrent engine trouble that affected multiple cruises took patience and perseverance for Justin Morton