Originally Posted by roozbeh
2-stroke engine, hard to start up, I changed the spark plug. And still...
This is what happens when I try to start it: So I get some speed then release the clutch to engage the engine. However, right after I release the clutch the bike slows down as if I pulled the brakes. So the engine does not start up. (P.S. IT WAS NOT LIKE THIS WHEN I FIRST BOUGHT IT) and thanks for any help!
Assuming since you have run the motor previously you can tell if the motor is turning over or not? That is the first thing you need to nail down, is the motor turning over when you dump the clutch? If not then you probably have a clutch problem.
If the motor is turning over but not starting then you have a whole other set of things to check. First thing I usually ask of people when their motor suddenly doesn't start is "did you turn the fuel valve off when it was parked", I read about people flooding out their motors pretty bad when the fuel valve is left open on some motors (proper float function should prevent this but...). If you have a flood condition, in addition to cleaning/changing the plug you should roll the bike around a bit with the spark plug removed and clutch released, the motor will turn over and blow air and any fuel in the cylinder out through the spark plug hole. (make sure there is no SPARK or flame around that will ignite the fuel that may come out, also make sure no debris is drawn in the spark plug hole) Often times a no start bike will start right up after doing this.
You should also check that the air filter is not clogged up with dirt or oil residue, see if she fires up with the air filter removed? Check the spark plug boot to see that the electrical contact is still intact. Disconnect the kill switch to make sure it isn't killing the ignition. Make sure fuel is flowing freely from the tank. All the basic stuff, beyond that you will have to give some more info to get better advice.
Also, before the rings seat on a brand new motor the compression can be kinda low (motor turns over very easily), once the rings seat the compression goes up and it is much harder to get the motor to turn over. Perhaps you are just feeling the additional compression and need to build more momentum to overcome it than when the motor was brand new?