Oil jets? Are you referring to the oil pressure relief valve? If so there's only one and it screws in you can't dislodge it, not unless you've snapped it off which would take a bit of doing. Pictures would help?
I will try and upload a photo.
Mate where in the Haynes manual does it refer to these "oil jets" in the crankcase? I've lost count of how many FZS600 engines I've stripped, I've never seen an oil jet with a spring and ball bearing. I've seen 'oil pressure relief valve' which does have a spring and ball bearing in it, but there's only one.I'm seriously curious and interested can you either post where it refers to oil jets or post some pictures please.
Oh got you now, you mean oil nozzles yes there's 2 of them. Sorry I don't use Haynes manuals just Yam workshop, different terminology If it fell out that would suggest the oil ring has gone brittle, which could be a sign of overheating, due to crap, low or no oil, they as a rule don't fall out.