Well said BRush,
CC, since we are advised to look at the insulator base for color vs tip, that may suggest it may not be super-critical which plug you use to jet, since at the insulator base, the surface temp will be very similar between plugs due to that area's proximity to the plug's metal (heat-conductive) shell? I suspect?
Am I the only only one who dislikes the way a 7-plug works in their bike?
I'm suggesting it may be susceptible to preignition.
If I use a 7, of course its fine and 'normal' in the woods, but then rev it out along the corn, then reduce the throttle or chop it, the bike will surge, ping, etc, not pretty. Its OK under load but I think it leans up a bit as throttle is reduced, and sets it off.
This was jetted at the 'fat' side of optimal, I'm pretty sure,
(45 1173N-2 155 as 5/8, 40:1 YammaLR, delta valve, dg pipe, fresh crank seals, 70F, 400'.....)
Drop in an 8 and it (the glow-plugging) all goes away.
If I had to make a 7 work, I'd have to go much richer, and give up a good chunk of 1/4-3/4 throttle responce. Got my sudco 5- needle set to play with now, but any thoughts or similar experience?