[rollscanardly]

let me tell you a few spec's first, im running a stock cylinder 67mm bore, rad valve, trx 6 pipe, cool head with a pump gas dome 38mm AS carb 45 pilot, cej needle 2nd clip and 160 main jet the plug is a BR8ES.

The trail i ride to get to the flat fast stuff is rough and rocky, also uphill....about half way up i stalled it and she was bubbling in the overflow bottle for just a second after it cut off....Well after letting her cool off a bit, i turned it around and went back down(was a bit tough to start, but not that bad), made a pass down the field and she ran pretty good went back home and took the plug out to find this: Seems there is about 1/16-1/8 of an inch of the side elctrode ?burned? off

http://www.geocities.com/rackemqwik/

I've done a little reading about spark plugs and wonder if this could be prevented by using a br9es, or if my pilot jet is too lean, and lugging it up the mountain caused it heat up. She does have a bit of a bog off idle when i hammer down on it(lean pilot?). I checked the compression on the engine while the plug was out, and it is still at 180 psi, just like before it was started for the first time


Thanks, Hunter

 

[C-Leigh Racing]

How your describing, sounds like a combination of things.
1st off, where your riding, the slow pace on & off the gas through the ruff part, the jetting might be just about right but then again just a tad rich for the area.
# 2, if you leave the jetting like it is & then go to the flat & push it hard, you could seize it up from being to lean.

If you was to jet the carb so it would perform real good in that ruff stuff & the slow going pace, when you got to the flats, you would lock it up for sure from it being to lean.
Looking at the plug pic, the plug looks like it has had time running real rich, because it is so black & then later, the no shine & flat ashey look, it was to lean almost to the point of seizureing the piston.
Lot of times you see this kind of thing when more than one rider is riding a machine & one rider is a more advanced level than the other & run it way more harder than the other.

Far as the plug looking odd, burnt, only answer I may have is it could be an ignition issue of some sort, never had one burn like that but I dont use resistor plugs, never have.
I know the book calls for a resistor plug to be used, but theres a bunch that never have used them.

I would say, you probably need to jet a bit larger for when you ride the flats just so you wont lock it up when your on it hard & then try to set a faster pace through the ruff stuff using higher rpms to keep it from loading up. Might be hard through the ruff to do that, but I cant see you jetting the carb down for that area & then it surviving out in the flats.
Neil

 

[rollscanardly]

What kind of plug do you run instead of the resistor ngk?
I had an off idle bog so it might be bit on the lean side with the 45 pilot jet, and possibly my needle too?...i noticed duncan racing recommends a dgh needle on the 4th clip which is richer than the cej 2nd clip im using.
I have a dgj needle to try, how much a difference will it make being one size leaner on the needle diameter?

Thanks, Hunter