compression?
 

I've got a 150cc jmstar and I cleaned the carb and did a compression test, but it's reading 125 on my compression so I put a little oil in the cylinder and compression jumped to 150. So I think it may be the rings.. And also when I start it up it'll run fine for about 30 seconds then the motor revs high without me giving any throttle. any suggestions to what it could be?

Possible air leak in the intake somewhere. Also have the valves been adjusted?

If putting oil in the Cylinder raises compression, then you probably have a scarred cylinder, or wore rings.

How many miles have you put on it? If it is new or low mileage the rings may not be seated. If there is a lot of miles on it you can make plans for new rings or top end.