The latest on my no-spark on the 550

The beginning is here: http://xjbikes.com/Forums/viewtopic/t=44080.html


The steps are copied form Page 6-10 of the manual

1. Check entire ignition for connections
*Done. Checks out. Grounds are good.

2. Check battery for voltage and specific gravity
*Done. New and fully charged

3. Check fuse and fuse connections
*Done. New fusebox, new fuses.

4. Check resistance of ignition coil
Primary: 2.5 Ohm +/- 10% at 20C/68F
Secondary: 11 KOhm +/- 20% at 20C/68F
*Done. Primary - 3 Ohm, Secondary - 20 Ohm

5. Check pick-up coils resistance
650 Ohm +/- 20% at 20C/68F
*Done. One is 630, one is 650 on the nose.

The manual says that if all this checks out - replace TCI.


The only thing I am not sure of is the secondary ignition coil measurement. I measured between the inner contacts in the plug caps. Does the higher resistance mean both coils are bad?

 

I'd think lower resistance rather than higher would indicate a problem. Or an open circuit.

 

The secondary side of the ignition coils (plug wires side) needs to be measured WITHOUT the plug caps on.....the caps are resistive and will add to the readings. The 20K number with the plug caps installed is low, and it may be masking a problem. Best to recheck with the plug caps removed, and check each plug cap itself for resistance. The stock plug caps are 10K each, +/- 20% (thus 8K - 12K is "within spec" for each plug cap).

 

I got a used TCI and tried it out.

No spark.
However, with this box, as opposed to the original one, there is a spark when I turn the key on, but no spark when I crank. The original one, there was no spark at any time.

Now, there is absolutely no guarantee that it was any good, so this is still not conclusive.

Since I now have two TCI boxes neither of which appears to function, I took apart one. I managed to not screw it up too badly (It can be put back together) and now I know how they come apart. I also see where the coil driver transistors are, and I am pretty sure they can be replaced cheaply. I might try that just for giggles. As far as I understand the inner workings of the TCI, the transistors are the most likely thing to fry because there is a potential for a high-voltage spike through them if the plug wires are detached.

 

There are two more common failures... The transistors are one. Dried out empty electrolytic capacitors are the other.