I have seen many scooters (Honda wave/dream) with 17 inch offroadtires, so it schould be possible to get those small Tires for your Bike (Front 3.00-17-4PR, Rear 3.25-17-6PR) in Indonesia.
Just ask around, there are many shops selling normal tires, and they will help you finding offroad tires.
I found one place in Denpasar who sold Tires for Big-Bikes
Bought a 90/90-21 fronttire made in Indonesia for 285.000rp (22€)
It will not last forever, but grip is good...
Scooter-Tires start at 80.000rp
Adress of the shop:
Jl. P. Tarakan 25A, Denpasar, Bali 0361-8422143
Anyway, if you stay at the main-roads, you will not need Offroad-Tires in SEA
Greetings from Kupang West-Timor