Now what

[Wolf]

2000 KDX 200, Pro Circuit pipe, stock silencer, airbox lid removed.
Ran great up until yesterday. My jetting tests from a few weeks back brought me to the following: Wisconsin 75 - 85 degrees
45 pilot, 152 main, 1173 needle 2nd from top, AS 1.25 turns out.
This worked great until yesterday.
Granted it got a little colder (about 60 yesterday), but...
It makes not much sense to me how I can go from great to fouling plugs??? I thought the colder temps might lean it out just a bit?
I fouled 2 plugs within 20 minutes. Did not have the opportunity for WOT.
Help?

 

[canyncarvr]

Exact same type plugs?

State of the air filter?

You are correct. Cooler temps will call for richer jetting (other things being equal).

Did your bike smoke more than usual?

 

[beefking]

I had the same thing happen to me the other day. It was running awesome the ride before that, and then it fouled a plug in about 5 minutes of riding, not to mention it was smoking out the pipe really bad.

All I did was drain the carb, change the plug, and mix up the gas tank a lot by shaking the bike around. After I did all that, it ran just as good as before. Kinda strange.

 

[canyncarvr]

Gas from the corner pump is guaranteed to be one thing....different than it was last week.

The #1 reason I read that makes race fuel a good thing to use is its consistency.

That's not what you get from your one-each major brand gas station.

 

[Wolf]

That makes sense. I got gas yesterday too. Dang, I don't like that at all.

 

[canyncarvr]

Hey! It's an easier fix than a top end! ;)