[ifwinterco]

Motorbikes still overwhelmingly use chains, not sure why but there must be a good reason

[ReptileMan]

Belts are not suitable for passing lots of torque. This is why cvt are not that popular outside of small-ish cars.

[guenthert]

Harley Davidson, among others, uses belts. Torque isn't the issue in the context of m/c final drive. Chains are a tad more efficient, which hp obsessed customers fuzz about.