Married to ROC girl,want to bring big bike back with us

Interesting. I presume you want to do the “once-only-duty-free-import-of-a-personal-vehicle” thing, right?

Ben wrote some useful info, although it relates to cars. Don’t know whether you can do the same with a bike.
[Forumosa - Taiwan's largest and most active Taiwan-oriented global online community in English … 935#200935](Import a car for personal use - #5 by Ben

You should read the rest of that post and the whole thread anyway. You should also read Plasmatron’s post on the import process for bikes here;
[Forumosa - Taiwan's largest and most active Taiwan-oriented global online community in English … 324#112324](Motorcycle touring - #51 by plasmatron