Put it back together and see what is going on, or isn't going on which should be. I would say that any 'dealer' I know of, would reassemble the bike and get it operational to maximize profit. I hope you bought this basket case for next to nothing, because in my view a basket case is worth more in parts than what it would sell-for as a 'non-runner' with the hope that it could become operational.
I wouldn't bother replacing the friction discs and 'steelies' before you have it operational, if as you claim they're in-spec. I'm assuming you will be using a new clutch cover gasket. If you put it back-together, and get it running, you will find out if it had a bad second gear, or that the clutch slips, or any other work which needs to be done. You probably don't have any idea of how-long it's been sitting, Drain the carbs individually, see what comes-out. Visualize the gas tank interior. If it's rusty, and not shiny clean inside, that's a job you need to do to get it operational and reliably so. The carbs will be 'knackered' from rust particles if the gas tank is rusty. There are plenty of threads on here about cleaning the carburetors and the gas tank. For the gas tank only I suggest cleaning vinegar, 6% works well, and it's easy to dispose of. It can be re-used as well for cleaning other steel or anything iron, just do-not use vinegar on anything potmetal like the gas sending unit inside the gas tank or the carburetors. Replace the sending unit with a blank-off plate, or immerse the entire gas tank in a vat of vinegar, sending unit removed. Electrolysis also works but you need to be very careful doing it.
If the engine needs a second gear replacement, and you cannot do that yourself, that's a $2000 parts and labor job here in the USA. You may decide to buy something not needing that expenditure, if you cannot fix it yourself. What good is the expense of a new clutch if second gear is bad, and you don't want to spend the $ on it?
Say that you get it together, and running, and you find the clutch slips, it's easy to remove the clutch cover with a new gasket on it, which has not been baked on there from a couple hundred heat/cool cycles. I suggest using a thin coat of water-soluble jel, like KY, on the two metal surfaces of the clutch cover & engine case, it helps hold the gasket in-place for reassembly and it helps the gasket to not tear when you need to remove the cover if indeed the clutch is slipping.
Tell us how things are going.
so it was never reassembled. No other explanation is available now so I hope the guy is ok.
