> Does anyone have a "chart" showing TR6 spark plugs over a heat range from
> cold to hot. I'm running the stock Champion N9Y and want to try some that
> are a range or two hotter. Brand doesn't really matter.
For almost any given brand of plug, the letters determine all the plug physical
dimensions, while the number is the heat range. Unfortunately they differ
between brands as to whether a higher number is hotter or colder. For Champion,
higher numbers are hotter. The Champion chart I have lists the following plugs,
in order from hottest to coolest :
RN16YC5
RN14YC
R/N12YC
R/N11YC
R/N9YC
R/N7YC
R/N6YC
RN4YC
The trailing 'C' indicates Champions "Copper Plus" line of plugs, which replaced
the 'standard' N9Y. The leading 'R' indicates an internal resistor, for EMI
suppression (and where I've written R/N it means the plug is available both
ways).
The other thing you could try (if you want) is one of the newer plug designs
that have wider heat ranges.
Interesting to note that the plug specified in my TR6 owner's manual is a UN12Y.
Not only a much hotter plug than you are using, but the leading 'U' indicates an
"auxiliary gap", which I assume is to improve starting with fouled plugs. Seems
like Triumph must've had trouble keeping the plugs clean, too.
Randall
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