soon after we got the 450 irs i did the bike ciurse, there was a neaerly new 420 there, had the ineviatable run off up across the field.The Honda 420 was its replacement for the 350, so remember this when your comparing price. I would compare a yam 350 to a Honda 420 and a yam 450 to a Honda 500.
Yamaha 350 has rated towing weight of 500kg
Honda 420 rated towing weight of 385kg
Yamaha 450 rated towing weight of 600kg
Honda 500 rated towing capacity of 600kg.
I haven’t looked at a 420 for a while but they are definitely lighter built than a Yamaha 450. Should make them easier on fuel though
the 420 only just edged it