10w40 oil - 5w30 is too "thin".
SS or FS? It shouldn't matter that much. I'd stick with better - full synthetic oil all the way. Some will disagree.
However, if it starts burning oil when you pour 10w40 grade in it, THEN it there's probably something wrong with the engine - worn seals, pistons... Then you can start looking for a new engine, rebuild current - while in the mean time you can use semi-synth 15w50 oil.
Oh, and do check for "obvious" things like some seals leaking - clean the bike thoroughly and look for any oil leaking. Does it drip somewhere when you park it?
SS or FS? It shouldn't matter that much. I'd stick with better - full synthetic oil all the way. Some will disagree.
However, if it starts burning oil when you pour 10w40 grade in it, THEN it there's probably something wrong with the engine - worn seals, pistons... Then you can start looking for a new engine, rebuild current - while in the mean time you can use semi-synth 15w50 oil.
Oh, and do check for "obvious" things like some seals leaking - clean the bike thoroughly and look for any oil leaking. Does it drip somewhere when you park it?
Most things done in a hurry need to be done again - patiently.