Very weird new ignition coil problem

I rebuild my engine, and i bought two new ignition coils on eBay (id or di i dont recall the brand) engine is running awrsome. after just 800 miles , this morning i wanted to start the bike and the engine was running only on cylinder 1 and 4.
I took the tank off , the 2 and 3 coil is shot.
My multimeter read infinity on the primary, low voltage side.
I had to connect my old coil and the engine is running perfect again. Plenty of torque and smooth.
My question is: what can cause a new coil to break only after 800 miles? :blink:
It was a factory problem of the coil itself or i should search something else? Can a low voltage connection (maybe a bit loose) cause that?
Thank you, happy summer!

Is the phrase "MADE IN CHINA" somewhere on the coil? Ed

Hahaha i really dont know. But i think those coils are Not made in china. I cant find the link..

They don't always say that. Even new good coils can fail. What's the return policy? If none, I don't buy.
Steve

Im now worried for the other coil.. I hate driving with those suspence
Are tourmax coil good? I was thinking about But them

I don't blame you. I've had good luck with used KZ coils. I have three sets as spares but I bought a pair of used Dyna coils in good condition. I paid about 1/2 price and if one goes bad, I know where to get a new one.
It's not that I'm cheap, it's that money isn't flowing like it did when I was still working full time. Semi Retired. :whistle:
Steve

If you have a Dyna S ignition, you shouldn't leave the ignition on for more than a few minutes without the engine running, or the coils and the Dyna itself could be damaged from heat build up. If your new coils aren't the correct resistance for your ignition, again, they could be damaged from overheating.

Sometimes you just get a defective part. I had a coil that would cut out after about 30 minutes of running time. After it cooled down, it would fire again....it only measured 0.1 ohm out of spec when I checked it....

I bought a pair of coils on eBay too for my 650 restoration and discovered the exact same thing as you - coil pack for 2&3 goes dead.
It happens in under 5 minutes (of non-continuous use of course, I've never gotten the bike to run yet).
It measures out close to but not exactly what the advert says it should (ie: I get 5 ohm, not 4 ohm readings but they are consistent with each other).
Basic problem of DOA, new part still remains an issue tho. I contacted the seller who eventually responded and told me this has never happened before. I can send it back (at my expense) and he will replace it.

This is the eBay item I bought:
[ Looks Stock(ish) but clearly NOT ]

One of the steepest learning curves with these old bikes has nothing to do with the bike itself but learning how to be a better online shopper (which I have failed multiple times now )

If you have a classic anything, there are going to be those that try to sell you junk. Chinese knock off's whatever. Even well known and respected sellers can get faulty equipment. (Speedo's come to mind) It's their return policy I look at first. If they won't exchange or refund within a year, I don't buy. eBay is different. You have much less time unless the item comes with it's own return policy. The term "buyer beware" applies in any case. :dry:
Steve

The three-word warranty is usually found in an obvious location on the product...easily understood by many who read it, and can sometimes be easily peeled off if you wish.
On top of that, labor costs will not be covered. :kiss:

Do coils have correct resistance for whatever ignition is fitted?
Higher resistance is usually okay, but lower than specified resistance for the particular ignition at hand could result in coil failure.

Good Fortune!

shamal wrote: I rebuild my engine, and i bought two new ignition coils on eBay (id or di i dont recall the brand) engine is running awrsome. after just 800 miles , this morning i wanted to start the bike and the engine was running only on cylinder 1 and 4.
I took the tank off , the 2 and 3 coil is shot.
My multimeter read infinity on the primary, low voltage side.
I had to connect my old coil and the engine is running perfect again. Plenty of torque and smooth.
My question is: what can cause a new coil to break only after 800 miles? :blink:

It's junk quality or it's used.