Help No Spark Please Suzuki

**virusmac** · 15th February 2005

JUST BOUGHT AN SUZUKI RM125 1984 TO RESTORE WHEN I BOUGHT IT HE SAID IT NEEDS A NEW C.D.I UNIT I NOW THESE ARE EXSPENSIVE BUT I MANAGED TO GET ONE CHEAP. I BUT THIS ON BUT STILL NO JOY SO I CHECKED FOR A VOLTAGE COMING FROM THE C.D.I TO THE COIL AND THIS WAS FINE 17 VOLTS SO I THOUGHT IT WOULD BE THE COIL AND REPLACED THIS BUT IT STILL DOESNT WORK AND I HAVE TRYED EVERYTHING.

CAN SOMEONE PLEASE HELP!!!!!!!!

**Pegasus** · 15th February 2005

If you are reading 17 volts at the ignition coil then I would get a new multi meter.

Failure of the CDI unit is incredibly rare, my money is on the ignition stator being shagged.

P.S
Please don't type in block capitals, it makes you look like an AOL user.

**tiggerbiker** · 15th February 2005

anything more than 14v to the battery would indicate a regulator/rectifier fault.

**Zippeyrude** · 16th February 2005

where are u reading the voltage?
leads perhaps?

**Lighty** · 16th February 2005

To test your rectifier/regulator. There is no way to do this 100% conclusively, since it's pretty much a sealed box, and you cannot precisely test on the component level. But some things can be tested.
There are a few diodes in the circuit, which should permit current to pass by in one direction, but not in the other (a little like Gore-Tex does with water). Usually in the case of a broken stator these diodes are fried, and turned into ordinary wires, permitting current flow in both directions.

If you were to get your meter and from memory??? here goes its been a long time but......
(+ not all rectifiers are the same )
put your Negative (-) Black test lead on the Red cable,
then try the Positive (+) Red test lead on all the following one at a time:-Yellow, White/Blue, White/Red, Black/White. And also your Positive (+) Red test lead on the Black/White and then your NEgative (-) Black test lead on the following one at a time White/Blue, White/Red and Yellow
Now in all cases there you should get Continuity.
Now do the same tests, but with the test leads REVERSED. In all cases you should see discontinuity (infinitely high resistance).
If you dont then your regulator/rectifier is knackered so replace it immediately before your stator windings end up knackered too unless they already are.
Hope this helps
Cheers

**cosmicma** · 16th February 2005

last time i had trouble like this it turned out to be the wiring harness ( rg 250 about the same age same cdi unit i think ) it was killing cdi units for fun
first thoughts was the magnito so changed that ( wasn't that )
eventually got round to putting a fresh harness on and it cured it

i,m not saying it will cure your problem as the simptons was slightly different mine would run but wouldn't rev above 3/4 grand it took a while to work out because everything appeared to work

**virusmac** · 16th February 2005

i am getting 17 volts from the c.d.i to the connection at the coil but i dont now if this is the correct reading and would i still get a reading if the c.d.i was f***ed

thanks for all the suggestions anyways will try them out.

**dirtyrider** · 17th February 2005

I had and used to race a 1984 Rm 125 E it was 1 of my better bikes at the time.
I agree with Pegasus more than likely your stater coils are shagxx as mine went too:
You can either get another from a breakers (for info 1981 rm125 will fit too) or get a rewind.
I had a 1983 CR125 before and the coils were knacked and it still produced a current.
Good luck.