Hi...brand new member here. suggested this thread.
Anyway from reading the thread intro, it seems like this bike might be quite old....

Nishiki Bushwhacker
18" frame, 21 speed, rear U-brakes, single-unit handlebar&stem
Serial CH 2543

(FYI, The site won't let me attach photos, until I make 10 more posts..)

Anyway....per your serial no. criteria, Canadian-made by Norco....1978 ?!?
Any correction and insights much appreciated.