Manuel Vagnon ... We have to put a name! And "Manual of talks" was menssongé ... I do not criticize the educational side explaining many engines (2tps, 4tps, different injection mode etc ...) nor the Yamaha (only engines of this firm are shown!), But it seems more sensible to me treat motor interviews (commissioning, drain, change rooms ...) !! I recommend it as a bedside book ... and not as a guide following you everywhere and leaving you all the annoying situations :)
