Bike

[RDFL]

Seems to fit better here than ebay. --  https://www.ebay.com/itm/Yamaha-Moto-Bike-Vintage-BMX/224148753056?hash=item34304e8aa0:g:4vQAAOSw-LtfVqs5

[SoCal250]

Missing the chain guard, and that seat is wrong and the struts are all wonky. There are a couple of them on eBay right now. I recall seeing the Moto-Bike in an old Yamaha catalog from the mid-70's. Kawasaki and Suzuki also built BMX bikes in that era.
And 45 years later, Yamaha is back at making bikes again, although this time they're electric.

On the BMX topic, DG Perfromance also built bikes in the late 70's.

[Djg8493]

And now for $35 (slightly used) you can get the smaller kits version of the Yamaha YZ one.