how to check cdi

[kev]

how do i test if the cdi unit is working on rt 125?

[DAVID THOMPSON]

have we under stood that relay 19 powers cdi box
no power on red white wire = no cdi power

i have never had a report that a cdi box has failed on a 125
but almost always when a problem is solved on a 125 the relay 19 is involved
it is a safety cutout relay and most of the time it does its job VERY WELL by keeping
the bike from running at all period! bikes very safe when they do not run
it is the biggest pain in the bikes wiring...
the tachometer on mine was giving funny readings 3 days later r 19 died
leaving me sorting electrical in the dark by street light

there is a white 3 wire plug near cdi box under rear of seat
the red white should measure +12v with key on ..if not back to relay 19 and the red/white wire in between the 2 points
dave
bikes very safe when they do not run
had a friend with an old triumph he never had a wreck on it ....it never ran long enough at one time to get to the site
of an accident
bought a honda and wrecked it almost weekly
extra note
the cdi will probably not fire the coil unless the motor is being turned over by the starter motor
it must be fired by a signal from the crank timing sensor
if cdi is not powered then back to relay 19

the starter solenoid if you can hear it click the big contacts in side are bad and dirty and its not passing enough current to run the starter motor
this failed on mine in 2003 its a standard Yamaha ATV part ..number listed in a past post on this site i am looking for it
D

[kev]

this is like a crash course in 12v electronics for me but im starting to picture how it all works, i shall attempt the relay bypass idea in the morning in the morning and report all finding back here for future reference

best wishes
kev

[DAVID THOMPSON]

the starter solenoid died on mine at the bmw moa rally on sunday morning at charlestom wv
when i went to leave for home
when i shorted across the 2 big nuts on the back of it the bike started
so i made a jumper plug and rode it home letting the end of plug stick out from under the seat