It really depends on your age but staying a couple of years, but there's multiple different visa options like education and retirement if you are over 50.
Make sure you have insurance that specifically mentions riding motorbikes on international licences. You also need a bike licence in your home country, if you don't and ride a motorcycle in Thailand nothing you have means anything.
Just setup and register a school, make a curriculum and teach people something, plus hire 4 Thai people. That should be all you need to do to do it yourself.
If you want a simple education visa, you can go to the school or go through an agency and it's exactly the same price.
If you don't want an education visa and are over 50 with 800k in the bank it's easy too. Do it yourself 1900 baht.
If you are over 50 and don't have 800k in the bank go down some back alleys and you will find someone who knows someone who knows someone in immigration and you'll pay and get a visa.