Remember these motors are OS based and like to run a little "looser" than other brands. It sounds like your JX is in its prime-enjoy it, I would say you should get another 2 or 3 gallons easy before you need to worry about. Although it is a good idea to take apart and check bearings, they should be good but its a good idea to check them regularly. Most I have seen get 7+ gallons before there are any worries, then repinch and its good for another 4 gallons or so.