First off, this is my first post here, I've been reading for years, finally signed in.
I'm pretty familiar with bikes in general, but nothing past the early 80's or so.

Well, anyway, I went the other day to look at a used boat motor, and came home with a free bike.
The bike is in pretty nice shape, and even my size but I've never run across the brand before.
Who made Mikado bicycles? There's a Taiwan decal on the seat tube and the model says Sportster on the top tube.
There is no tubing decal but its not super heavy and looks to be a decent mid grade bike. My guess would have been a $200-250 bike back in the day.
Most of the components are 1979-1980ish, Shimano 400 5 speed gears, Sugino Maxy crankset, Ukai convex?? alloy 27x1 1/4" rims, Sunshine large flange hubs, springer Cycle Pro padded saddle, Long white wheel reflectors, and Dia Compe center pull brakes. Even the old gumwall tires are still nice, showing no real age and still with little nubs on the tread.
When I asked about the old bike hanging in the rafters the guy said "Take it, it ain't been ridden since his kid graduated high school in 81".
It looks like it never got ridden at all. The rims have no brake wear, the only rusty spots are on a few dry chain links, and the paint is 95% perfect or better. Best of all its my size. I pumped up the tires and took it for a ride, every last bit of it works like a new bike. It shifts perfect, rides perfect, etc. The worst thing I found so far is that the little plastic nuts on the reflectors are dried out and cracked.

It looks a lot like any other Asian import from that time and reminds me a lot of the import model Schwinns or Raleigh bikes from that period. There's a number on the bottom bracket that reads OC504028.
I've got a few other same era bikes here and it really looks like a same era Nishiki Sport or Custom Sport, it don't match any of the Giant built Schwinn bikes, the lugs, chainstay style, and general fit and finish is better than say a Schwinn Traveler or similar.

If it had no badging on it, I'd probably have guessed it to be one of the later Asian built Raleigh bikes or a Nishiki clone.

One more detail that stands out, its got what appears to be Stainless Steel reflectorized rat trap type pedals, pretty much like the type that came on just about every run of the mill bike back then but in stainless steel. There is no branding on the pedals anywhere that I can see, but they do have removable dust caps and serviceable bearings.