I have heard that it is a larger liability for some shops to work on something ten years or older. Simply for the safety reasons of it being older. They have to inspect more things before they let the bike leave because if they dont and something happens then the shop is fucked. Say a customer wants his carbs cleaned and the shop does it but does not inspect any thing else, i.e. dry rot on tires possible rusty chain or other stupid shit that can cuz the bike to wreck. Then the customer takes off and and the thing runs great but the front tire happened to be dry rotted and it pops and the dude wrecks and hurts himeself. He could try to go after the shop saying that they should have told him that. This is why, also with cars, people at repair places always offer to fix something or tell you something is wrong if they see it. As long as they tell you or offer to fix it for you they are covered. If they offer and you decline then they have that written in their notes " Customer Refusal"