I can't believe a regular 3-5K on a working 45 year old twin these days... perhaps to Schedule 5 or some view of it? Which perhaps means it will all fall in a heap one day and someone will end up with the $40K 100 hourly when it all catches up.
Maintaining a single to manufacturers scheme averages out more than that... just paid 7K for 5 year old single. (Yes, I know I must be mad when I could have done it so much cheaper
)