Hey guys I have recently brought my first bike a cbr250r mc19, when I brought the bike it was not staring or even crankng, I replaced the starter motor and battery and then the bike would crank but not start, since then I have replaced the fuel pump, filter and fuel lines, rebuilt the carbies, replaced plugs and leads and ensured firing order was correct and now am basically out of ideas as to what else may be stopping the bike from starting any suggestions I could get as to what may be preventing it from running would be greatly appreciated

 

Check ground wire/cable. All fuses, coils? im not familiar with the 250 but if you got juice and its cranking, but your not getting fire that would be a place to check.

Take a plug out, put it in the coil plug and hold it against a spot on the motor/frame and have some one crank it over and see if you have spark.

Make sure your not holding the very end of the wire or plug. might make your hair stand up for a bit.

That will tell you if you have spark, if you have nothing and you didnt already do it, check the ground cable and fuses and try it again. Still nothing, you could have a bad coil/wire leading to the coil.

Just a few places that id start at.

 

A gas engine takes 3 basic things to start: spark, fuel, and air. Figure out which your missing and trace your problem from there.

As Dirtrider009 suggests, start with checking for spark. If that proves to be good, check for fuel supply and fuel getting into the cylinders. Make sure you have good compression and air flow into the motor.

Has the motor been apart since it last ran?