[Drahken]

Does anyone here recall a particular motorcycle based toy/playset which was sold in the late 70s, but was gone by the mid 80s? It might have originated earlier, but based on the motorcycle/rider designs, I don't think it was earlier than the 60s at most.
These are childhood memories of a toy I have seen anywhere for about 4 decades now, so I can't be certain of the accuracy, but from what I recall;
It was a racing playset with a tower/mountain design and a rigid black plastic road/track winding down around the outside, with slots for the motorcycle wheels. The motorcycles were a little smaller than matchbox cars, were mostly a solid piece of single colored plastic, with a permanently moulded in rider, and the set came with 3 or 4 in different bold colors (red, blue, green for certain, and I think yellow). The design of the motorcycles was a streamlined crotchrocket type, with the rider leaning over the bike. The underside of the motorcycles had a wide steamroller type wheel in the back to keep it upright, a very thin but relatively large diameter wheel in the front which was designed to fit in the slot in the track, and a steel bearing pressed into a hole in the middle, which acted as an additional wheel, and provided weight to pull it down the track.
You would place a couple of the motorcycles (I don't recall how many, I think just 2) in their track slots at the top of the tower, then release them and watch them race to the bottom, powered entirely by gravity.
I had this toy at either the very tail end of the 70s or very begining of the 80s (78-81 or so). I have not seen it anywhere (not even in people's houses or thrift stores) since the mid 80s. Given the small size of the motorcycles, the presence of steel bearings which could pop out readily (the part of the toy i remember most is one of the motorcycles, without the bearing, that lingered in the bottom of my toy box for many years), and the simplicity of it's concept and play mechanic, I strongly suspect that it got discontinued for safety reasons. (Anyone young enough the not get bored after 5minutes would surely have been a choking concern, while anyone old enough to to swallow them would lose interest in it quickly.)

I have been trying off & on for many years now to get info on this toy, but without any luck. Does this ring any bells with anyone here?