Why does that happen?

[Geoff Hastings]

Thanks Michael, I forgot the plugs can also the resistor type. The caps I’ve fitted are non resistor type but I believe they should be 5k ohms.

[Tim Allman]

Thanks Michael, I forgot the plugs can also the resistor type. The caps I’ve fitted are non resistor type but I believe they should be 5k ohms.

All of the ignition parts for bikes (and cars) at the time were non-resistor. I'm amazed that your C95 works as well as it does with the resistor style parts. My CB77 runs poorly with resistive caps and plugs. Sadly it's getting very hard to find the non-resistive types.

[Geoff Hastings]

Hi Tim,
I don’t think an ignition system should run both resistor plugs and caps, one or the other but not both. They are just for radio interference suppression. My bike is now resistor free so the locals will hear me pass but not from the exhaust noise!

[Tim Allman]

I think you misunderstood what I wrote. This should be clearer.

My CB77 runs poorly with resistive caps and/or plugs.

[deuce_7]

NGK D8HA spark plugs currently available are the non-resistor type (no "R" in the plug number). Many of us probably run this D8HA plug. (Denso equivalent is non-resistor X24FS-U). I think Honda intended for the HT ignition path in our vintage bikes to be non-resistor from the coil, through the HT wires, caps and plugs.

Interestingly, two years ago NGK stopped offering the non-resistor spark plugs that are commonly run in vintage British bikes; e.g., NGK non-resistor B8ES is now only offered as resistor BR8ES. Brit bike owners were reassured that running NGK resistor plugs in vintage analog ignition systems would have no negative effects. (From my experience this is correct). And, NGK also offered that resistor plugs are more ideally suited for digital ignition systems, by decreasing potential radio frequency interference (RFI) issues.