One needs a long term Thai Visa to register/plate a Thai plated vehicle in Thailand. The Visa could be a tourist Visa of 6months or longer, or a business/employment/retirement Visa which are >6mth duration/validity.

It could also be helpful to have a 'house-book' (home/property ownership document) in your name, as that might suffice even if one had a 30-60day tourist Visa, to get a Thai plated vehicle into your name.

There are agents that can assist with the formalities, for a reasonable fee...
I paid about 600THB for the agents fee I used. The actual cost of registering ownership, including inspection was about 2400THB on the CB500X. Keep in mind this in Bangkok however, and different jurisdictions might have different rules and costs etc.

Welcome to TIT... 1000x better than a TIC any day of the week IMHO.

YMMV...

PS.
TIT = mammary gland
TIC = parasite that feeds of a host

...just saying