While I agree with you that motorcycle wear on the road is fairly minimal, more than bicycles and less than cars, the best way to handle it is that roads get paid through tax on gasoline, not any other tax. That’s something to lean on politicians about. Politicians should not be allowed to get away with sneaking other taxes through to pay for things that other taxes were originally set up to do.
Actually, they cause the same amount of wear in multiple tests - negligible to undetectable. Zero equals zero.
Also, what of diesel, electric and natural gas powered cars? If you only tax gasoline, why should these people get a free ride?
Tax *all* road users or tax none. No free riders.