Engine in the bike, or engine out of the bike? (it's easier if the engine is on the bench)
It's going to be a few hours of labour, several hundred dollars at normal rates. The labour involved is like that of setting the valve clearances (including replacing the shims) - either way, the camshafts have to come out and be re-timed on re-assembly, and there's four camshafts that need to be done.
If you want to trim the labour down, remove the camshafts and remove the sprockets from the camshafts yourself, get them machined, and re-assemble it yourself at nominal cam timing. Make scribe marks before taking the sprockets off the camshafts so that you can put it back roughly where you started. Then the labour is only that of doing the actual degreeing. It's still aggravation because you have two sets of camshafts to do, but at least you won't have to pay for a camshaft removal, re-install, and re-time.
