After 7 years of weekly visits to the thrift shop, something finally showed up. Looks to be a beat '91 Seven 21 with bonded alu tubes. It's been mangled into a single speed but I can't find any frame issues or cracks and it tracks straight. I was worried about a smaller seat post crunched into the cluster but it came out easy and the ears popped back out to reveal a normal gap. Has great weight weenie potential. It also has that weird braze-on under the down tube...pump fitting?
Looks like original front wheel and tange headset. Everything else is a bodge. I LOVE the custom millwork on the Custom swaged crank. Angle grinder perhaps? And who needs stem insertion lines. Amazing.
Price was right. The wheels seem to be fine, straight rims, tires hold air.

I've missed out on two Miyata 310s at my local shop over the years in nice condition, for $30 each.

I happen to have a nice 310 sitting on the bench right now. Not sure which one to build and in which way. I think this frame is a little up the food chain.

Any Miyata guys know if these frames are constructed like the Koga Miyatas? They seemed to make a lot of these bonded alloy. I'll google some pics.

Dont see photos.

Hmmmnn, thx

I saw them the photos the first time I looked at this thread, but now they're gone for me too.

Now?

Miyata was a Japanese frame building company that was in long time partnership with Dutch bike company Koga.

In Europę most of the Miyata frames were sold as Koga Miyata since 1970s. Koga was selling bikes on all level - including high end road bikes (Koga Miyata FullPro) and touring bikes (Koga Miyata Randonneur Extra).

Koga Miyata frames used Miyata's own steel tubing. The best frames were build using triple butted Hardlite FM1 tubes.

Koga Miyata is a company that sells bikes in Europe up till these days. They still produce high end touring bikes like Randonneur.

The bottom bracket braze-on was for a CO2 cartridge inflater. Probably was a time trial or tri bike n new. Looks like it got the urban bike makeover.

The Koga-Miyata frames were built in Japan by Miyata, then shipped to the Netherlands for assembly by Koga. Your frameset is actually a bonded main triangle with CrMo stays and forks. Basically it followed the path laid out by the Raleigh Techniums in trying to combine the best traits of aluminum and steel. I also suspect that there was more than a bit of cost reduction driving things, at is eliminated the need for high paid brazers, the need to mitre tubes, etc. This technology shift followed on the heels on the big Yen revaluation that was lowering the competitiveness of Japanese bicycles. I'm just happy to see that the frame wasn't drewed in the conversion process.

I think they called them the air bottle basement or something like that, there was a thread here about them a few weeks ago.

Sweet score on the bike Clubman!

Me too, it's all there. This one will get the rattlecan treatment and a friction Suntour drivetrain. Might be a nice ride.

I remember that...thanks just re-read it. I think I'll mount a deer whistle instead.