So on my last ride last year I had the bottom cyl fail on me, I managed to limp it home on 1 cyl.

I pulled the plug and it was of couse soaked. I grabbed a couple new plugs put them in and still no bottom cylinder firing. Pulled the plug, grounded it and kicked it over, there was a spark, weak and intermittent.

So to eliminate the possibilit of a coil issue I swapped the coils and then the problem duplicated itself in the upper cylinder, not firing, and the bottom cylinder now fired. Ok, so I figure I will order some coils from Tyga.

Procrastinated all winter and still haven't ordered them! I was reading last night the fantastic post on coil testing...now I am confused.

Both of my coils test to the same specs. .3 ohms between terminals however they both have a resistance of 28.9 from terminal to boot.

My question is this, are both coils in need of replacing...if so why did bottom coil NOT work in the top cyl if the specs are the same and why did the top cyl coil work on the bottom?

Confused, and is there only the rear coil avail new?

Thanks for input fellas.

So were you getting a spark from both coils on the bottom? I would be checking your circuit on the bottom coil, also consider if you connectors are not corroded or gummed up not giving you continuity.

Honestly, it's only a coil, replace it and don't worry about it

nope, getting a spark from the top cyl coil wherever I put it and none from bottom coil no matter where I put it.
What has me puzzled is that they both read the same on my meter....

so you have a continuity issue in your wiring then.

You mean in my harness....

all your wiring, not just the harness...from source to supply. Give things a jiggle as you measure too.

I would try replacing the suspect coil first.
I would think the rest of the loom wiring is okay if the original top coil worked when you swapped it to the lower position.
Sometimes electrical components can break down under load. They can test okay for continuity, then fail in use.
Also it's harder for a spark to jump under compression. Putting more load on the ignition system than when the plug is just layed on the cylinder head.

Chester, that makes perfect sense.

I have just ordered a pair of coils from tyga!

Thanks for input fellas.

wardlaw wrote:Chester, that makes perfect sense.

I have just ordered a pair of coils from tyga!

Thanks for input fellas.

One thing I would also check, is maybe just swapping the plug caps over and see if the original front cap was causing the fault.

I'd assume the front plug to be okay if you didn't swap them over with the coils originally.