Problems and Retro-fit
I thought the headtube was 1 1/8, but it turned out to be 1 ¼. I really don’t know how common 1 1/4 was in the early 90’s but there couldn’t have been a lot of them. I ended up needing a 1 1/4 to 1 1/8 reducer to make it fit.
The crank on the bike was a Standard size, meaning the chainrings were 46/36/24. Back in the middle to late 90’s Shimano switched a compact drivetrain, 42/32/22. They have now switched back, so I needed either a very old or a very new front derailleur to be compatible with the Standard. Fortunately my friend at the LBS had a newer front derailleur. Since it had a 26.8 clamp, which won’t fit on most new bikes since the industry has gone to larger seat tubes, he just through it in for no cost. A little more history here. Shimano's idea of a compact drive train meant smaller chainrings and smaller cassettes They reduced the 5 arm triple crank BCD from 110/74 to 94/58 and then to a 4 arm crank BCD of 104/64. The idea was to reduce weight. However as 9 speed cassettes grew to 34 teeth, there was really no point to the compact cranksets and Shimano went back to Standard size chain rings but stayed with the smaller 104/64 BCD.
The Yokota had three sets of cable stops on the right side. They where meant for the rear brake and derailleurs and the bike had a hanger for cantilever brakes. Since I was going to upgrade to V brakes, I had to run a brake cable down the right side. Unfortunately, I ran out of black cable and had to use white, but that’s easily fixed.
And that was about it. The only other issue was it looked like some had just taken a hammer and pounded off the old headset. I ended up filling the divots, masking the headbadge and repainting the headtube. It was more of a hassle than I thought, until I discovered I needed to wait 48 hours between coats. You can see some of the divots if you click on the seat tube photo.