trappermike
ArboristSite Guru
Ok,here is how to find your ignition problem in your RM125,and other similar Japanese bikes....
First off,you generally cannot test the "Magical" CDI box unless you have a special dealer tool worth about $1000 and most dealers never had them,but you don't need to. It's a process of elimination,since you can test all the other components. You need a shop manual to get the testing specs,sometimes the aftermarket manuals have the specs too. All you need is a muti-meter and you are just doing resistance tests-ohms.
Test the generating coil under the flywheel,it should be within resistance specs and the windings should not test(Have continuity) to ground.
Then test the trigger coil,same thing,should be within resistance specs and not grounded.
Test the coil,there are resistance specs for the primary and secondary windings,and the coil can be actually tested(made to fire spark) on a coil tester.
If all checks out then it's probably a bad box.
Note-Be sure coil is grounded properly,sand paint from the frame for a clean contact where it's bolted to the frame.
Also check the spark plug cap,it often has a resistor,if it's over 5000 ohms resistance it's no good,replace it,and you can buy plug caps without a resistor too.
And of corse replace the spark plug,one can become fouled in a few minutes in bad conditions.
First off,you generally cannot test the "Magical" CDI box unless you have a special dealer tool worth about $1000 and most dealers never had them,but you don't need to. It's a process of elimination,since you can test all the other components. You need a shop manual to get the testing specs,sometimes the aftermarket manuals have the specs too. All you need is a muti-meter and you are just doing resistance tests-ohms.
Test the generating coil under the flywheel,it should be within resistance specs and the windings should not test(Have continuity) to ground.
Then test the trigger coil,same thing,should be within resistance specs and not grounded.
Test the coil,there are resistance specs for the primary and secondary windings,and the coil can be actually tested(made to fire spark) on a coil tester.
If all checks out then it's probably a bad box.
Note-Be sure coil is grounded properly,sand paint from the frame for a clean contact where it's bolted to the frame.
Also check the spark plug cap,it often has a resistor,if it's over 5000 ohms resistance it's no good,replace it,and you can buy plug caps without a resistor too.
And of corse replace the spark plug,one can become fouled in a few minutes in bad conditions.
