Ignition coil life?

[montmil]

The recent "new spark plug leads?" thread went from plug wires to coils to horns. Me? I'm easily distracted so figure it's all good. It did bring up a question...

My '81 R65 appears to have its original gray ignition coil. Maybe the bike's just been lucky. However, I still have a bit of a spark problem on the left jug. The new plug leads, caps and NGK sparklers helped but all this chat about elderly cracking coils has me a bit concerned.

Question thrown out...  If the coil is an OEM installation, then it's 27 years old. Is it possible that it's still up to snuff at this advanced age? Even with no visible outward signs of checks/cracks, might the slight unwillingness of the left jug to light off as well as the right side plug be an indication that the coil needs replacing? Might a new Dyna twin coil be in my future?

I plan to retorgue the heads and set valves this weekend. Perhaps get the new fork seals installed. Mother-in-law visiting my bride for their college homecoming so I'll be spending some quality time in the garage.

Help me burn up my credit card just a little bit more  

[Bob_Roller]

With the history of this particular coil, it's a good bet that it will fail, and most likely at the worst possible time.

My original grey coil failed on me after 13 years, gave me no real warning, just quit 2 blocks from home.

I replaced it with the upgraded OEM 'red' coil, the upgraded coil started giving me problems after 10 years in use.

I have had the Dyna 'brown' coil for the last 2.5 years , but the R65 doesn't get the use it did before I got a second bike, so I don't know what kind of life I will get out of it.

The Dyna from Motorrad Elektrik is $90US including the mounting adapter braket.

OEM coil is around $130US.

[Rob Valdez 79 R65]

I have a different ignition (points) set-up than you, but I ran my original coils for 26 years when I decided to replace them just for the heck of it.  I got one of the last pair of cheap Blue Bosch 6v coils (like my bike uses) before they quit making them.  Now they have a different one that is the same, but more money, of course.

Anyway, it should be considered a consumable after 25 years, I would say.