[Rockatanski]

'75 360: new coils, wires, resister caps and NGK B8ES, but condenser is original. I've been working on it on and off since last spring when it was pulled out of a barn. While dinking with it last fall, the new spark plug went bad on the right side so I replaced both. When I did, I'm 75% sure that I replaced the right coil at the same time just in case (I had inadvertently ordered twice the coils and caps so I have spares).

Now that the weather is warm, started it yesterday and initially it wasn't running on the right side, then decided to. Then today it won't spark at all on the right side. I switched plugs around and confirmed that the plug is bad. That's twice now. Again, I haven't put hardly any miles on this thing yet.

What causes two plugs to go bad so quick on the same side? Do I try another brand of plug? Put the last new coil and caps on when I do? Replace the condenser even though the points aren't arcing? Auction the whole thing on eBay for $50? Give it to my brother? Soak in gasoline and light on fire? AAAAUUUUUUUUUGGGGGGHHHHHH!!!!!!!

 

[mike in idaho]

Have you cleaned/adjusted the points?

 

[Rockatanski]

Oh, yes, and insured that the timing is set. My brother convinced me to go ahead and put in a new condenser, then new plugs and try that. BTW, the points also look new and smooth, not pitted. They were new too when I did the above.

 

[Kim]

Had the same on my CL360. New points and condensers fixed it...

 

[Donthav1]

Do you have pictures of what the electrode end of the plugs look like?

Curious if it's a fueling issue & not electrical.

 

[Rockatanski]

Had the same on my CL360. New points and condensers fixed it...

Thanks. The points were new along with the coils but I think I'll triple check them. I put a new condenser on and will report back if it stops killing plugs.

 

[maltaman]

'75 360: new coils, wires, resister caps and NGK B8ES, but condenser is original. I've been working on it on and off since last spring when it was pulled out of a barn. While dinking with it last fall, the new spark plug went bad on the right side so I replaced both. When I did, I'm 75% sure that I replaced the right coil at the same time just in case (I had inadvertently ordered twice the coils and caps so I have spares).

Now that the weather is warm, started it yesterday and initially it wasn't running on the right side, then decided to. Then today it won't spark at all on the right side. I switched plugs around and confirmed that the plug is bad. That's twice now. Again, I haven't put hardly any miles on this thing yet.

What causes two plugs to go bad so quick on the same side? Do I try another brand of plug? Put the last new coil and caps on when I do? Replace the condenser even though the points aren't arcing? Auction the whole thing on eBay for $50? Give it to my brother? Soak in gasoline and light on fire? AAAAUUUUUUUUUGGGGGGHHHHHH!!!!!!!

'75 360: new coils, wires, resister caps and NGK B8ES, but condenser is original. I've been working on it on and off since last spring when it was pulled out of a barn. While dinking with it last fall, the new spark plug went bad on the right side so I replaced both. When I did, I'm 75% sure that I replaced the right coil at the same time just in case (I had inadvertently ordered twice the coils and caps so I have spares).

Now that the weather is warm, started it yesterday and initially it wasn't running on the right side, then decided to. Then today it won't spark at all on the right side. I switched plugs around and confirmed that the plug is bad. That's twice now. Again, I haven't put hardly any miles on this thing yet.

What causes two plugs to go bad so quick on the same side? Do I try another brand of plug? Put the last new coil and caps on when I do? Replace the condenser even though the points aren't arcing? Auction the whole thing on eBay for $50? Give it to my brother? Soak in gasoline and light on fire? AAAAUUUUUUUUUGGGGGGHHHHHH!!!!!!!

I have been going through the same thing. What I found out is that if you take the bad spark plug out and clean it with a wire brush it will work. What I also found out that is that the carburetor is running rich and covers the plug with carbon and does not ground itself. I have not checked that carbs yet since I hardly ride the bike.

 

[Rockatanski]

I put on a new condenser, addressed carburetor woes that I posted elsewhere, and looked forward to running it today.
Started it and found it running on only the left cylinder again. Pulled the right plug and it is wet. Checked for spark and it was weak, then intermittent, then complete failure. I swapped it out with the other and verified that the plug completely failed... the third one that failed from the right side.
Since everything's closed today, I'm going to install my last new coil and cap (mark the old coil), then Monday purchase new plugs, one heat range hotter if he has them.
Due to carb problems, the left has fowled (dry soot) much more but has never failed.
I guess I'll keep updating in the hopes that future generations and archaeologists can make sense of this one day.

 

[mike in idaho]

Coils getting enough voltage to fire?

 

[Rockatanski]

Coils getting enough voltage to fire?

Good question and I'll check that out today, but something is killing the right plug which I verified by switching them over.

 

[mike in idaho]

Check to make sure both sets of points aren't closed at the same time. This is what is referred to as "points overlap", it tends to rob the right hand coil of part of the voltage needed for a hot spark. Both sets of points should be adjusted to the high side of the adjustment range to keep that from occurring.

 

[Rockatanski]

I found the points closed at the same time, so I spread them a bit to the maximum setting, and they still close at the same time. The points are still very new new from when I started this project and I think them I got them from common motor.

I Also put on a new coil and cap for whatever that will be worth and we’ll get some new plugs tomorrow if they’re in stock.

 

[gogodirk]

check the ground on the coils.

 

[HenryNorfolk]

If you're determined to keep it as original as possible then I understand that, but I converted both of my classic Hondas to electronic ignition. The Boyer system I put on my CB350K2 includes a new coil unit. It works brilliantly.

 

[Rockatanski]

I would like to keep the points, but if I don't resolve this, then I will be forced to go electronic.

 

[mike in idaho]

Are you sure there isn't a carburetor problem, that is drowning the right hand cylinder?

 

[Rockatanski]

No, I am not sure and am about to update a separate post on my carb woes.

Having adjusted the points to the max, and installing plugs one heat range hotter, I was encouraged with the way it ran at idle as it warmed up. After two short rides, the right carb has some soot on it, and the left is fowled with dry soot. It ran good going out, very nice on the highway 4 to 5K RPM's, not so good turning around, sputtered through town, and died going up the driveway. The right has some soot on it- more than it should, and the left is very sooty.

Even if it doesn't fire because it has drowned, why won't it then fire on the left side? The left is worse but it hasn't killed a plug yet.

 

[Rockatanski]

I'm updating this post to close it out. I rode it a few times with the hotter plugs and have the carb situation nearly straightened out (another post that I'll update as well). The right plug should have failed by this time but didn't. I highly suspect that fowling was killing the plug, but why right and not left? The difference is the type of soot in the right cylinder, more wet and gooey rather than the dry of the left which I suspect is oil. Oil along with maybe two much fuel was killing the plugs somehow. If not that, then I'm open to suggestions.

While I still have repairs to make, I had it on the highway today and just LOVE this bike.