Yamakuni 7000 Al tubing

[Spankyfart]

Apparently - and that's all I can find is some Rocky mountains were made with this alloy tubing.
What does one know about this, was it any good?
I have an MTB that has these tubes.

It reads: Nippon Light Metals Yamakuni 7000 Series.


I discovered that they weren’t just a tubing supplier, they were actually one of the first Japanese companies to mass-produce welded aluminum frames. They made the 1986 Centurion Facet, and possibly the Miyata Omnium, Diamondback Arrival, and the Kuwahara Maragay MTB. Yamakuni and also made bikes under their own brand, including the “Yamakuni Wolf” and “Country Bird” MTBs, and an unnamed road bike identical to the Facet.

 

[Spankyfart]

 

[Volker]

Yamakuni also made some (Koga) Miyata (e.g. Ridge Runner ECS) and frames for Cilo and MTB Cycletech.

It is quite easy to identify the frames, since the frame number starts with "YA" [the following number indicates the year of production].

 

[troje]

Indeed there are Rocky Mountain frames with a serial number that starts with YA.