Got spark got fuel/air and my cr 125 still wont start?

i,ve come too a dead end with my dirt bike, the engine refuses to fire up.i,ve changed the air filter,plug and had the carb cleaned but it still wont run.even when i try to bump start it it just bogs no matter what throttle position. ive checked the spark which is fine,ive even sprayed easy start into directly into the carb but still wont kick over.ive checked the reeds, looked into the cylinder through the reed intake which looks fine there's no oil in the cylinder or on plug. the only thing i think it could be now is the piston rings, there is compression there but how much i don't no? also back fires occasionally. could someone give me a point in the right direction before i strip down the head thanks.

oh buy the way its got good fuel in it and ive not long got so dont know how old the piston and rings are.Got spark got fuel/air and my cr 125 still wont start?its probably compression. remove the spark plug, and if you dont have access to a compression tester, have someone kick it over while you put your finger over the hole. if it blows your finger off every kick, (just a nice easy kick- not kicking furiously) it should have enuf compression. if you can hold it back with your finger, its dead.Got spark got fuel/air and my cr 125 still wont start?You haven't said the year of your bike so I'm guessing it's an old one where the timing needs to be set. Go to the link below and do some research.

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is it tough being a woman