@PoH
I generally use one of 4 methods of searching for JP raws likely on syosetsu.
1) Just copying the JP name and googling it, if there's a raw out there, it's usually on syosetsu. If it's not there, it's likely been licensed or removed, but those are somewhat rare actually, more so for 18+.
2) Copying the name and searching it on syosetsu
3) Find another novel by the same author on syosetsu, then go by their 'posted works'
4) Find a genre / tag you're very , very sure it would be tagged under, then find a novel with that same tag/genre and search through that tag/genre.