'83 R65 Not cold starting

[rounders]

I nearly placed an order on EME yesterday for a 0.7 Ohm coil but hesitated - I never like throwing parts. Given the state of this coil though, it might be justified.

[gspd]

I see. I'm still running the OEM crack-coil .....and it is indeed cracked.

Ta-dah! Look no further. Replace it.

[rounders]

Ta-dah! Look no further. Replace it.

I will be both thrilled and flustered when you turn out to be right! Placing an order now...

I'll report back after replacement, for better or worse. Thank you for the input.

[gspd]

I will be both thrilled and flustered when you turn out to be right! Placing an order now...
I'll report back after replacement, for better or worse. Thank you for the input.

If I'm wrong I'll give you back every penny you paid me
Either way, a 'real' airhead owner needs a spare coil lying around for times like this.

[gspd]

While you're at it, check your HT wires with a ohmmeter to be sure they're in spec and that the ends aren't corroded into the coil.

[barryh]

I nearly placed an order on EME yesterday for a 0.7 Ohm coil but hesitated - I never like throwing parts. Given the state of this coil though, it might be justified.

Did an 83 R65 really have a 0.7 ohm coil ? I thought the original crackomatic dual output coil was 1.5 ohms and didn't change to 0.7 ohms until much later.

[Kurt in S.A.]

Just for my own understanding, how would a cracked coil affect the performance of the ignition? I've heard about the cracked coil breaking down during wet weather riding or maybe after washing...sort of makes sense. But that's not the situation here. In a static situation what does the crack do to make things not work? Is it the humidity in the air that gets to the windings? Just wondering...

Kurt

[gspd]

Depending on their severity and their location, the crack(s) may or may not immediately affect performance.
Your bike is 40+ years old, probably still has the original coil.
Those coils weren't renowned for instantaneous cold starting, even when new.
Consider any visible crack as an unsubtle warning that failure is on the horizon.

[barryh]

Just for my own understanding, how would a cracked coil affect the performance of the ignition? I've heard about the cracked coil breaking down during wet weather riding or maybe after washing...sort of makes sense. But that's not the situation here. In a static situation what does the crack do to make things not work? Is it the humidity in the air that gets to the windings? Just wondering...

Kurt

The crackomatic coil has been discussed on the R65 forum and the fact that it was assigned that name suggests failure was common enough. Symptoms ranged from only a problem in the wet to wouldn't start at all even when dry.

If it is the coil causing your symptoms then the presumption would be that the coil can produce a healthy spark at atmospheric pressure when the HT voltage demands are relatively low but then begins to break down when a higher HT voltage is demanded of it under compression. HT voltage will take the easiest path perhaps through an internal short rather than firing the plug. If this is happening when the coil is dry, the situation when wet might be it doesn't produce any spark at all.

Even if the coil is not the cause of your problem, replacement would still seem a wise move.

[Rob Frankham]

Just for my own understanding, how would a cracked coil affect the performance of the ignition? I've heard about the cracked coil breaking down during wet weather riding or maybe after washing...sort of makes sense. But that's not the situation here. In a static situation what does the crack do to make things not work? Is it the humidity in the air that gets to the windings? Just wondering...

Kurt

The crackomatic coil has been discussed on the R65 forum and the fact that it was assigned that name suggests failure was common enough. Symptoms ranged from only a problem in the wet to wouldn't start at all even when dry.

If it is the coil causing your symptoms then the presumption would be that the coil can produce a healthy spark at atmospheric pressure when the HT voltage demands are relatively low but then begins to break down when a higher HT voltage is demanded of it under compression. HT voltage will take the easiest path perhaps through an internal short rather than firing the plug. If this is happening when the coil is dry, the situation when wet might be it doesn't produce any spark at all.

Even if the coil is not the cause of your problem, replacement would still seem a wise move.

All agreed... the other factor is that a cold engine at cranking speed requires a lot more spark energy to 'light the fires' than a hot engine one running. This will often explain why and engine that runs (on the face of it) perfectly will be difficult to start. This may be due to a faulty coil or indeed any one of a number of reasons most of which have already been discussed.

But, yes... by all means replace the original coil. They are a known source of issues... although to be absolutely fair, if it's the original coil and it's been on the bike since it came off the line, it really doesn't owe anyone anything.

Rob