Topic: Spark arcing from spark plug cap

[bryanj]

Forget Clymer, you need the specs from a genuine Honda manual

[papi_sosaa]

[...]

[...] I ordered this Ignition coil kit from 4into1 and I'm just curious about resistance.
https://4into1.com/ignition-coils-caps-and-wire-honda-cb650-gl1100-1200/

That set of coils would also be my choice.

As a matter of fact: that set looks ideal also for CB Fours with conventional breakerpoints ignition. Just add a 2 Ohm ballast resistor in the primary route. I favour screw on connections like these coils have. I can't comment on the quality of these particular coils though.

I don't think my coils are bad, I don't trust the Chinese quality coils and I do have a spare set of OEM ones if my current OEMs are actually bad.

Replace the plug in any case. BTW, did the hole in the old cap look like it had burned through from the arcing, and was it in the same location as the arcing now?

I'll run over to my parts store tomorrow and grab some new plugs.

I believe the arcing is in the same place however the old cap looks like it got chipped rather than burned.

well that cap is #$%*ed for a start.

That's the old cap, it's still arcing with the new cap.

Forget Clymer, you need the specs from a genuine Honda manual

I've been making due with the Clymer but I'll see if I can find one.

[Ozzybud]

[...]

[...] I ordered this Ignition coil kit from 4into1 and I'm just curious about resistance.
https://4into1.com/ignition-coils-caps-and-wire-honda-cb650-gl1100-1200/

That set of coils would also be my choice.

As a matter of fact: that set looks ideal also for CB Fours with conventional breakerpoints ignition. Just add a 2 Ohm ballast resistor in the primary route. I favour screw on connections like these coils have. I can't comment on the quality of these particular coils though.

I don't think my coils are bad, I don't trust the Chinese quality coils and I do have a spare set of OEM ones if my current OEMs are actually bad.

Replace the plug in any case. BTW, did the hole in the old cap look like it had burned through from the arcing, and was it in the same location as the arcing now?

I'll run over to my parts store tomorrow and grab some new plugs.

I believe the arcing is in the same place however the old cap looks like it got chipped rather than burned.

well that cap is #$%*ed for a start.

That's the old cap, it's still arcing with the new cap.

Forget Clymer, you need the specs from a genuine Honda manual

I've been making due with the Clymer but I'll see if I can find one.

The honda manuals are on here in pdf format

[papi_sosaa]

Forget Clymer, you need the specs from a genuine Honda manual

I've been making due with the Clymer but I'll see if I can find one.

The honda manuals are on here in pdf format

There’s nothing for the 1982 CB650SC.

[scottly]

Did you replace the spark plug yet?

[scottly]

Replace the plug in any case.

I'll run over to my parts store tomorrow and grab some new plugs.

Any updates???

[papi_sosaa]

Replace the plug in any case.

I'll run over to my parts store tomorrow and grab some new plugs.

Any updates???

I bought new spark plugs, I'm just waiting on my new HT cords to come in. I also found out my petcock was leaking while taking the tank off so I'm waiting on that too.

Technical Service Manual is also on the way.

[scottly]

I bought new spark plugs, I'm just waiting on my new HT cords to come in.

Why are you replacing the plug wires??? The ignition system appears to be working fine, as it is throwing a very strong spark! The problem is it's somehow escaping to ground on one cylinder. BTW, I think Dave meant that the new cap may be compromised by the arcing going through it, burning a carbon path.

[papi_sosaa]

I bought new spark plugs, I'm just waiting on my new HT cords to come in.

Why are you replacing the plug wires??? The ignition system appears to be working fine, as it is throwing a very strong spark! The problem is it's somehow escaping to ground on one cylinder. BTW, I think Dave meant that the new cap may be compromised by the arcing going through it, burning a carbon path.

I wanted to replace them because I think the plug wires are a little too tight. Especially with #4, when the cap goes onto the spark plug, the top of the cap is resting against the block and the wire backs out of the cap a bit.

Might be a little excessive but I just want to cover my bases.

[scottly]

That's not where the arcing is; the power is making it through the wire and into the top of the cap. If the cap is hitting the block, is it the correct cap? What about the #1 side, does it's cap hit the block?

[papi_sosaa]

That's not where the arcing is; the power is making it through the wire and into the top of the cap. If the cap is hitting the block, is it the correct cap? What about the #1 side, does it's cap hit the block?

#1 and #2 are okay, #3 and #4 are tight.

[scottly]

Please replace the spark plug.
PS I don't care if the replacement is resistor or not; it's no big deal.

[papi_sosaa]

Please replace the spark plug.
PS I don't care if the replacement is resistor or not; it's no big deal.

I'll update once I get the parts and get it started. In the meantime, I'm fixing my left fork so I can test while the weather is still decent. 

[scottly]

Please pull the plug and inspect it for cracks in the porcelain insulator and /or any black carbon traces.

[papi_sosaa]

Please pull the plug and inspect it for cracks in the porcelain insulator and /or any black carbon traces.

Compared #4 with #1, both plugs look fine. Reading 4K Ohms on #4 and 3.8K Ohms on #1.

[scottly]

Got pics of the plugs handy? The problem is somehow the spark is being conducted from the threaded end on the plug past 1 1/2" of insulation and through 1/16" of cap insulation before arcing to the head, when the path of least resistance should be through the center conductor in the plug and a .028" gap. This is not a common issue.

[papi_sosaa]

I didn't realize it until I pulled the plugs out but I've been running DPR8EA-9 plugs with a 0.35 gap all summer :S Besides a carb issue when I finished the build in May, the bike has been running fine (up until recently). Regardless, big oof on the plugs.

My brain must've been on autopilot when I was buying plugs; either I bought what was in the engine before from the previous owner or I didn't pay attention and grabbed the wrong plugs at the auto store.

I replaced the spark plugs with DR8ES-L with a 0.25 gap, new HT cords, coils, and resistor caps this evening (HT cords/coils/caps from 4into1). After warming up, #1 and #4 seem to be fine but now #2 and #3 are arcing similar to how #4 was with the wrong plugs. Going to try twisting the cords on #2 and #3 again but if they continue to arc then I'll try putting the old coil back in.

On top of this and my forks, my carbs are acting up so that's another thing to look into.

Sure glad this is happening now and not at the beginning of the season.

[scottly]

Are you putting any kind of grease or anti-seize into the caps or on the outside of the plugs?

[papi_sosaa]

Normally I do put dielectric grease on the ceramic part of the plug but I wanted to make sure everything was running fine before I did it.

[scottly]

So there's dielectric grease inside the caps now?? NEVER put anything on the ceramic part of the plug!! 

[papi_sosaa]

No, there's no grease on the plugs or inside the caps at this moment.

[scottly]

No, there's no grease on the plugs or inside the caps at this moment.

Are you sure about that? The use of grease is a smoking gun for your quite unusual problem. I was wondering about it before, but since the problem then only involved the one cylinder I dismissed it. Now the problem has moved to two other cylinders, and the common denominator is the grease.

[Don R]

  Scottly beat me to the post, I was saying the same thing.

[papi_sosaa]

No, there's no grease on the plugs or inside the caps at this moment.

Are you sure about that? The use of grease is a smoking gun for your quite unusual problem. I was wondering about it before, but since the problem then only involved the one cylinder I dismissed it. Now the problem has moved to two other cylinders, and the common denominator is the grease.

New plugs, new coils, new cords, new caps. No grease was applied yet and now, never will be.

[scottly]

When you installed the new caps over the old plugs with the grease, the rubber seal would have squeegeed some of the grease onto the seal, and then when installed on the new plugs some of the grease would have transferred from the seal onto the new plug. Try cleaning the plugs off, and swab the inside of the caps with q-tips or something, and clean the seals as well, or leave them off for now, as they're mostly to keep water out when it rains. Brake cleaner might help, but if the grease is silicone based, it can be hard to remove.