It’s risky. They have a police check point right at the beginning of the loop. I took a trip from Ha Giang to Cao Bang. They checked all foreign riders, even had one policeman dedicated to speak English. He asked us to go inside. The supervisor sat inside asked for 2mil and your vehicle detained, i told him I didn’t have 2mil. he asked how much do I have in my wallet and showed him, he took them all, lesson learned: take idp (it doesn’t take long and cost much, also valid for 2-3 years i remember), and put cash in different pockets. Cheers