Reviving a Derelict Miyata

 I picked up a Miyata 100 that was evidently sitting outside unused for many years. Since I have a fair collection of used bike parts, I figured why not try to get this one working again with what I have. 

 First, I had to cut off the rusted chain with an angle grinder (there was no way it was going to move). 

 Even the freewheel was stuck and refused to rotate backwards. I actually unscrewed it from the hub when I put a chain whip on it. I still wanted to save it though, because it is a SunTour Perfect freewheel with a 32 tooth low gear. That's pretty rare to find. After soaking it in automatic transmission fluid and torching the outer bearing race, I was able to unscrew it for disassembly. Inside, the ball bearings where all rusted and the pawls were sticking. After cleaning everything up, the pawls moved freely again. I threw out all the rusty ball bearings, and added all new ones (1/8" size). Upon reassembly, the freewheel worked perfectly.

 The seatpost was a bigger problem. It's an aluminum post that was fully inserted in the steel frame, and thus was essentially welded in place. I soaked it for days in transmission fluid, and heated it repeatedly with a propane torch: 

 

 My poor little bench vise still wouldn't budge it. However, a pipe wrench with a cheater pipe attached was able to rotate it slightly: 

 I thought I had won, but that was only the beginning. There was still so much corrosion holding it in place that I needed to bring the frame to a friend's house to use his sturdier bench vise to twist it out. It put up a big fight, and we had to stop and let the seatpost cool down in the snow from all the friction from twisting the frame around it. As the aluminum warmed up from friction, it expanded and created a lot more resistance. We finally got it out after an hour of wrestling with it, and then had a well deserved beer.

The bottom bracket was another problem. Water pooled up inside, and rusted the bearings:

 There's no way to reuse any of those parts. The spindle and cups were way too pitted from rust.

The lower headset cup was very rusty on the outside. I couldn't fix the pitting with rust dissolver, so I ended up replacing it with another similar cup that I had. I removed it with a tool I made from EMT conduit years ago:

 Installing the replacement cup with a vise:

Next I moved on to the wheel bearings. The quick release skewers didn't want to come off, so I used a vise grip and a towel to unscrew them:

Fortunately the bearings inside didn't look too bad:

 

I cleaned them up with mineral spirits, and replaced any balls that looked pitted:

Next I reassembled the bearings with fresh grease, and reinstalled the freewheel:

 

 

 

 I used an M5 tap to restore the threads in the quick release nut. I simply held the tap in my vise, and then spun the nut onto it using pliers to turn the nut:

 

 The QR lever was also very sticky, and needed to be disassembled and cleaned:

 

 Back to the headset. I soaked the bearings in mineral spirits, and then packed them in grease:

 

 

Next I reinstalled the fork and screwed in the upper bearing cup:

 

 Then I tightened the lock ring after adjusting the bearings so that the fork can move freely without play:

 

 Finally I could tighten the top nut:

 

 

This was a good time to touch up the paint and give it a coat of wax. It's really impressive how well the original paint held up. It doesn't even look faded. Well done Miyata.  

 

Now it's time to install more bike parts. I took a set of bottom bracket bearings from my parts stash, and greased them up with new ball bearings: 

Next I installed them in the frame with a replacement 115mm spindle:

 

 Then I reinstalled the cranks (the steel chainrings and bolts cleaned up well with rust dissolver):

 The right side pedal was super stuck, so I used a tip from the great Sheldon Brown and tied the left crank to the frame. This let me use a cheater pipe on a wrench to unscrew the pedal:

 Damn you, galvanic corrosion. Fortunately, the pedal cracked loose and left the crank threads intact. I replaced the rusty pedals with nicer looking ones from my local bike co-op (my hobby wouldn't be possible without them).

 I also scored a used pair of tires from the co-op as well. Check out the originals:

Its starting to look like a bike again:
 

For the handlebars, I cut off the rotting foam grips:

 Then I installed the bars and stem on the bike. As a tip for aligning the brake lever heights, bridge a yardstick between them so you can better see if they're the same height. They are slightly crooked in this photo:

 I wrapped the handlebars and installed the brake and shifter cables:

 Then I installed a replacement chain:

 Adjusting the derailleurs took a lot of effort because the set screws were rusted. I eventually got them shifting nicely, however. Lastly, I installed a white saddle and took it for a well deserved test ride:

 This bike came out better than it had any right to. Despite being an entry level model, it survived with most of its original components still working. Even 40 years later this bike looks great, although it took a tremendous effort to revive it. Cheers!