Pickup Coil Diagnosis?

[Guest Thainglo]

I'm continuing to have trouble with getting a spark out of my #4 cylinder. All ignition and pickup coils passes the resistance test in the service manual. Swapped pickup pins from #3 to #4, that would generate a spark through the #4 ignition coil. Believing I had the problem isolated to the TCI, I first swapped transistors on the original unit then purchased another TCI from ebay. After resolving some interlock issues, I'm having the same problem with spark on 3 cylinders, none on #4. Is there another way to verify the pickup coils are working or non-functioning?

 

Here are my resistance tests on the pickup coils:

#1 119.7 Ohms

#2 122.2 Ohms

#3 118.7 Ohms

#4 115.9 Ohms

 

I'm wondering if the contact area for that coil is not any good, would that still show good resistance?

 

Any thoughts?

[FROG MAN]

You need to clean the pickup coil connector that plugs into wiring harness left of bike behind foot peg along frame. The female connector provides the tension to make a tight connection. I have had to take a pin extractor and remove the female pins one by one and re crimp both ears slightly to restore the contact.Same thing goes for the TCI plug. When the engine is running the vibration of the motor can cause one or more of the contacts to go intermittent. The only way to verify the pickups are good is to use a O-Scope and monitor the pickup pulses at the TCI for consistency when running.

[GeorgeS]

Also, Check out the Circuit " From " the " 15 Amp Ignition Fuse " You will be looking for any EXCESS High Resistance Across the following components.

 

---- Service Manual, with schematics, is avialable on line, this web site , ------

 

Apply CRC 2-26, or Equivilant Electrical Contact Cleaner, ( Radio shack carries, this, or Home Depot, and Lowes for the CRC brand product )

 

1. 40 Amp main fuse, Open and clean fuse element, tighten screws that hold element in place.

 

2. You migh have high resistance ACROSS the " ON-OFF " contacts of the Ignition Switch, ( give it a bath with CRC 2-26 ) ( blow out with compressed air, and repeat )

 

3. 15 AMP, Ignition Fuse HOLDER> Check the Prongs that hold fuse in place, They are brittle and crack and break, Clean the contact surface.

 

4. Your " RUN - STOP " Switch on right handle bar. Water gets into the switch, the contacts Corode, and turn into High REsistance Contacts. ( thus, lowering voltage to coils, and TCI )

 

5. Follow the two wire cable from the Run Stop Switch, forward, to behind headlight. There is a pull apart connector, on that cable. Open it an clean it.

 

--- All of the above item's can in- ject Series , IN Line , Resistance and Cause a Voltage Drop, to the 4 Ignition Coils, And the voltage Supply for the TCI.

 

In other words, instead of 12V to the Ing Coil Primary windings, you " Might " have a lower voltage there. In one case, one fellow found only about 4 volts avialable to fire the coils. ( because of excess series resistance in the above components )

 

--- Also, Check your Charging Voltage at Bat. + Terminal, with Engine running.

Make sure its at Least 13.8 Volts, should be 14.1.

IF not, you might have Battery Charging Problems.

 

--- Is your Battery " Fully Charged " ??? Charge it at 2 AMP Rate, for at least 6 to 8 hours. ( With a real charger, not a trickle charger )