The Pattaya police have been order to crack down on people driving motorbikes and cars. You need to have proof the motorbike you own is really your or that you have consent from the owner to drive it. If you do not have then police will confiscate the motorbike or car.
They will off course crack down on foreign passports as well so at least have a copy of your passport with you while you driving. I have seen many police on the streets the last week always standing on the same place every night and ranking 100 of people every day for not wearing a helmet.
Do not risk a fine or worse, just wear a helmet and keep your passport and motorbike documents close by.