Hi,
I just bought an 85 trx 125, and it doesn't have any spark. It cranks over great and the primary coil is putting out around 35 volts, but the cdi is not sending any juice to the secondary coil. Does any one know how to test the CDI or pulse generator to see if they are working right, or maybe have one for sale cheap.(This is a christmas present for my 2 little brothers and funds are limited)
Thanks,
Dennis

 

You should have 35 volts at any point on the bike. CDI's are not testable aside from taking one off of another running bike. I think you have the primary and secondary coils misnamed. The best thing to do is to buy a manual that will give the specs and resistances. You should have around 12 volts going to the cdi.

Try this first. Set your meter for resistance and check the two prongs on the ignition coil (what your plug wire comes out of). What does it read?

 

Hi,
I proberbly do have them missed named, the one under the fly wheel has 35 v coming from it and the ignition coil has 0 ohms of resistance between the two prongs and 3500 between either prong and the plug wire(without cap).
Thanks,
Dennis

 

Dennis, I am not sure what that particular specs for your bike is, but you should show some resistance (usually .1-1 ohms depending on the bike) between the two prongs (ignition coil primary winding). Obviously, you know what you are doing since you already knew to check the plug wire and prong (ignition coil secondary). Your secondary is normally 2500-8000 without the plug cap so you should be fine there. Check the primary again and if it still doesn't show any resistance, pull the coil off the bike. Check to see if there are any signs of melting from it getting hot. Chances are this is your problem. New one should be less than $50 from honda. If you have another smiliar bike (electric 12v start) try its coil. Let me know what you find.

 

Hi,
I only have an anoulog(sp?) meter so there may be a slight amount of resistance and my meter is just not sensitive enough to pick it up. The problem is there are two wires going to the coil, and if I go from the neg. on the battery to the black wire with a yellow stripe i get a very small amount of voltage (like .5-1 volts). I was thinking I should have a much larger amount of voltage than that, any suggestions?
PS I appreciate all the help I have gotten so far!!
Thanks,
Dennis

 

When you read 1 volt, is that with the engine cranking over? You should set your meter to 12VAC and hook it up to the two wires that go to the ignition coil. Common (black test lead) should go on the black or black/white wire. The red test lead should go to the red or orange wire. Crank the engine over. Your needle (this is where analog meters come in handy) should jump up to 12 volts and back down every time the engine should fire.
Most analog meters are capable of reading as little as 1 ohm, so you should see some resistance from the coil if you are on the lowest setting.

If you give me your phone number, I will try to call you tonight. I think better when I can ask questions and get an instant response.

 

Hi,
Sorry for the delay, but I purchased a cdi and it didn't help the problem, my # is 207-645-2153 I appreciate the help.
Thanks,
Dennis

 

did you ever get it running? i just went threw the same thing with mine..

 

yea ive almost the same problem but i have a weak spark on my spark tester but not enough to go thur the spark plug.