Lets disect my spark plug.

[Billy Golightly]

Same Plug





Strictly wide open, less then 10 seconds of being off the throttle stop. Its a B9ES on a 250R, 39PWK 152 main 01 CR ignition. From the pictures I've seen around here, that bottom burn ring is about perfect I think, but the tip of it kind of worries me, although I've also read the tip does not mean anything. The plug I actually rode around on was about the same color as the burn ring the whole length of the porcelain. It was a little bit lighter chalky gray on the tip which I've usually associated with lean, but the side of the porcelain looked about the same as the burn ring on this one.

[Liquid-Darkness]

As long as your main jet is one size down from sputtering, I think its burning ok. What els can you do, besides richen up your low to midrange? When I first started jetting my bikes, I had the two main checks in my mind. I couldn't make a choice. It was either down one from WOT spudders, or a nice tan tip. Made me a little frusterated because I hear everyone talking about both or one is better then the other. Out here in the heat of Ca I had to go with the spudder method. I did not like the thought of being too rich, but I hate the thought of being lean. Too many mods at stake to blow an engine from being lean for me. What are you thinking Billy?

[Billy Golightly]

I honestly am not sure, thats why I've posted it. The thing is running insane. Theres not a drop of smoke anywheres and it pulls like a freight train. If I had to tell you where it was at without looking at the plug, strictly by the seat of my pants I'd say its running lean. But thats about the most inaccurate way there is, of telling how its running.

[SYKO]

derek moved me to a b7es plug in my R he said nothing else! or ELSE!

[4cylinders]

hey, gray can be too lean, transfering over heated aluminum to the plug. check out syko's, keeps wearing away until it won't run any more.

[Liquid-Darkness]

I would run a cooler plug with a shorter ceramic tip. Makes the engine run cooler I hear. The NGK web site says it transfers heat better with a shorter tip. Are those all the mods your R has above?

[Billy Golightly]

I'm already running a 9. Theres 10s, but there not really available around here locally. I dunno how Alan is running a 7 without melting something

The R has a ton of bolt ons, but this engine has zero internal mods. Bolt on wise it has a ported reed cage, boyesen carbon fiber reeds, fmf exhaust system, 39PWK with clamp on uni airfilter, and the CR ignition.

[edog]

Try one of these? I don't recommend these for plug chops.

http://www.ngk.com/sparkplug411.asp?kw=Iridium&mfid=1

Move the clip on the needle to the bottom slot.

[x.system]

That plug looks pretty good, here's a pic of mine from the last ice race I ran, 43 laps with practice, heats and main, I put a new plug in at every race (BR8ES). My bottom burn ring is a little smaller than yours by the looks of it. My plugs always look like this. I just pulled the top end for a new piston and rings for the new season. I figure I've got about 6 hours of wide open throttle on this piston for the 06 season.

My setup is stock bore on its second overbore I believe, 39PWK, rad valve, open air box, esr trx5, 55 pilot, 220 main jet, middle clip, DGH needle, air screw 1 3/4 turns out, cam 2/amsoil 50:1. Temp was about 5 degrees that day, 600ft above SL.

[edog]

Looks like the, spark was jumping to the outside.

[Billy Golightly]

Your plug makes me feel better x.system. Whats up with that red/orange spot though? That kinda color always makes me nervous, and theres a tiny spec of it on the end of mine.

[x.system]

Every plug I've had in it does that on the exhaust side. My gap is closed to around .017/.019, if I open it to .020 or above I get a sputter around 1/2 to 3/4 throttle caused by the 20 year old electrical system. That should be fixed here in the next couple weeks.

[Billy Golightly]

I'm running mine at .012 with the CR ignition. When I had the stock setup, like you, if I ran anything bigger then about 15 it wouldn't run right and that was even with a pretty low compression engine.