My friend & his wife bought a little 1966 Yamaha YGS1 for pennies on the dollar. It is an 80cc 2-stroke, cosmetically amazing, and mechanically complete. The seller said he just had too many projects and this was the lowest on the totem pole. The seller included both the original Yamaha shop manual and the owner's manual, which I was just over the moon about. They have no mechanical experience and wanted a fun project, so asked me if I could help them get it going.
We've been working on it a day or two per week over the past ~3 weeks. Let me tell you, the Yamaha shop manual is the least helpful thing I've ever seen.
For example, we pulled the cylinder head to inspect the piston and cylinder walls. When putting it back together I looked for torque specs on the cylinder stud nuts. Nothing. Diagrams and pictures are not as helpful as I'd want. No good details on almost any disassembly or reassembly procedure at all. The most it gives is "check that [X] is operating properly". Ok, how???
The other thing that is driving me completely nuts is the lack of info about specialty tools. We need to pull the magneto which requires a puller. My Honda manual is so good at calling out Honda part numbers for every tool needed at the front of each section that I was hopefully expecting the same thing from Yamaha so we could order the right size the first time. Nope. Just guesswork. Just 57 year old pictures and no numbers.
I'd say the one saving grace about working on this little bike is that parts are mostly still available and it is overall cheaper than working on my Honda. I'm just so confused about how shops even worked on these back in the day if they gave a damn about specs.
