Hi I can recommend the AA Book of the Car  for anybody looking to understand how cars worked in the 60's & early 70's  - The book explains the basics together with fault finding and  with 380 pages a good start and an easy read if you are new to maintaining your Triumph . Best source is Ebay and take your time in buying as the book can be purchased cheap. I paid £3.50 delivered on a buy it now . The book weighs just short of 2 kilos    Paul