i use rock oil: 2 stroke injector, fully synthetic. If it won´t start in the rain change the spark plug for a new one and make sure its screwed down tight. Water got into the wiring where the fuses go on mine so i dried it all out and squirted some silicon sealant all round the fuse holders which sorted it. If your bike still smokes a lot you may need the piston rings doing or try de-coking the exhaust.