Spark plug color. Possible lean

[albertp86]

I just finished riding my (race dome) and took a look at the spark plug ( br9es)and noticed that it had a yellowish color to it. I was running a 178 main in my 40.5 carb and noticed it was cutting out on top end as well. After several mains it ran at a 188 main. (I think to big). Bike ran good, never got hot but the plug didn't look great

The race gas 110 is ran at 50:1 bel rey as always. The weather was good 68 degrees. Needle position was in the middle.

I just cant think of why the color and now why do I have to run a main so big. I'm not leaking coolant either. Can it be the power valve? I have not checked that.

Anyone ever have a yellowish type of plug that was also very dry. (no oil on the plug). Thanks for any help

[Grande Huevos]

could be somthimg to do w electrcal system? try ohm everything out make sure its all working good, also could try running an 8 plug instead of the 9. and last of all that bel ray oil is trash!!! great way to harm ur motor try using maxim castor 927 or klotz

[albertp86]

I thought that it could be electrical cuz I did wash the bike really good 2 days before I came riding to the dunes. Being that the spark comes weak with the stock ignition I could benefit from a cr system or is there something else? I'm not sure how to test that electrical stuff. Something is leading me to that. I have never seen a yellow tip in the spark. Also, the only thing that I changed since it ran well was a fuel petcock and I washed it and the race gas was 3 months old in a metal container. So I am not sure.

[Thornfold]

been told no water on 250r's as leaks into ignition and rusts, clean dry

[Darthgeese]

you could always benifit from a cr ignition. Im really pullin my hair out with this ignition system, first good deal i see on cr im buying it asap

[KSRRider]

This is pretty cheap IMO: http://houston.craigslist.org/mcy/2169126859.html

Not mine, just passing it along.

[albertp86]

After thinking about my situation a little more, I'm thinking that I might have a power valve issue or something. I had to increase my main to a 188 from 178 to get the top end not to die. I am lost on this. Yellowish color on the spark plug and no oil residue at all on the plug. I can't get that thing to fowl. Any other ideas would be great.

[profab250R]

Try putting a lerger jet in there. like a 200 or something. see if it turns black or fouls out then. Also doube check your gap.