A Few Questions....

[TIGER72]

I HAVE A 2000 400EX ON WHICH I HAVE INSTALLED THE USUAL GOODIES- K&N FILTER, OUTERWEAR, AND A CT RACING SLIP ON. EVER SINCE INSTALLING THE SLIP ON, THE PLUG KEEPS FOULING. I PUT A NEW PLUG IN, RIDE IT FOR 3-4 HOURS, AND THE NEXT TIME I HOP ON, IT WON'T START. THE PLUG IS BLACK. I HAVE NOT REJETTED, I STILL RUN THE STOCK JETS, BUT I AM GETTING READY TO INSTALL A DIAL-A-JET. (CHRISTMAS PRESENT) I KNOW THERE ARE LOTS OF OTHER JETTING QUESTIONS ON HERE, BUT I WANT SOME INFO SPECIFIC TO MY QUESTIONS. ANY INFO IS APPRECIATED.

[jesshamner]

I just installed a t-4 on mine and I had to get a bigger main jet. You are probably running too lean. Once you install the dial-a-jet, it should run a lot better. I know how you feel. I was starting to worry when mine wouldn't run right. Everything is all good now. Good luck and let me know how that dial-a-jet thing works.

Something is wrong with what your saying, the mods you did should cause it to be more lean and the cold weather should add to this, but your plug is telling you its too rich.

If you are absolutely sure that the prob started when youinstalled the silencer then I would suggest you take it off and check it out to be sure there are not any problems with it like something blocking or stuck inside.

The other thing I was thinking is if your filter is clean and not clogged and if thats OK then I would be taking out the jets to see whats really in there, unless you have it since new and know there truely stock.