You can stay as long as you like on your EU nationality, rather than passports. However, I think you may complicate matters for yourselves with the actual physical lack of an exit stamp on your Canadian passports.

I also have dual nationality, but I have always entered (and been stamped in) as a certain nationality and been stamped out in the same passport so as to avoid some officious border pr1k having a reason to hassle me to over why I was stamped into a country,but not out.

Very easy to solve though, exit the EU i on your Canadian passport and then enter Montenegro/Serbia/BiH on your UK/Cro passports. Just turn around and reenter Croatia then using your EU passport and all potential future problems are averted. You basically swap nationalities in no mans land.

Be wary of EU border crossings (entry from non-EU countries) they like everything to be 'just so' and can in my experience be utterly painful to deal with.

Registering Canadian bikes onto EU plates may be easier or harder depending on the year, make and model and the country you are in. If you want to go that road, you will need an address and be prepared potentially for some eye watering import duties (varies by country) and hassle as regards getting the vehicles 'inspected'. The EU is legendary as a dual buerocracy, each country has its own ludicrous hoops to jump through as well as a second set created by the diktat of Brussels! You will soon discover why it is very hard to do anything of a business nature in the glorious fatherland........

Sorry EU. :st ormy: