^^ Yeah, no way you'd burden a motocross bike with electric start. Those old two strokes were pared down to nothing to shave every gram. And it worked. Look at the weight specs of those bikes, and it's shocking how light they were with very little or no use of exotic materials.
I'd moved up from my 80 to a 125 and loved the bike. Full sized chassis but super light with an engine that was Jekyll and Hyde. I scored a session on a CR400 and figured it would actually be easier to ride thanks to more cc's meaning a wider more useable power band. Whoops, nope. It was just a lot angrier! You had to ride the 400 exactly like a 125, keep it at full steam. You were just going a hell of a lot faster.
I loved Hondas approach to the CRs. "These are race bikes, you want easy, buy an XR."