Fouled Plug?

[TRFOXX]

I went out last night to start my 2001 400 and it wouldnt start
chocked it and still nothing. Checked the plug and it was wet.
Dried it off and put it back in and nothing. Put in another plug
and it started right up! My ? is im running a 152 main jet with stock settings. I put a FMF Powercore 4 S/A on a couple weeks ago with 4 1" Uni vents in the airbox with a Uni filter. My head pipes turned a little blue ever since i got the machine (running lean i guess) and spark plug was showing a little white. How can i be fouling plugs now and I have noticed a little bit of a backfire when started
but goes away? I totally confused back fireing and blue pipes means running lean, but fouled plugs means im too rich? Any help here would be great!

You sound exactly like I did about 2 years ago with my first 400. I put the same exact pipe on drilled holes in the lid and it ran like sh*t,,backfired, and I just wasn't happy.
What I would suggest you do to fix your problem is order a K&N powerkit and get it installed with the stage 2 kit,,,,This will fix your problem,,,no doubt about it,,and you won't foul any plugs anymore,,no more blue pipe,, and it'll start easier,,,and I just love what the kit did for me. Of course you can go buy a hand full of jets and hope you get it dialed in Ok ,,,but a lot of trial and error with that method,,,You get a jet kit and it comes with directions, elevation charts,,etc,,,,just trust me on this and you won't be sorry,,,and your 400 will really,,,come alive with this installed..good luck..

PS...leave the choke alone when starting it...but you definitly need to rejet,,,,that's your whole problem I noticed after I wrote this you have a uni filter,,,just order you a jet kit,,it'll fix your problem...garaunteed...

[TRFOXX]

Thanks for the advice Rico! But I found out what the problem was
it had the wrong spark plug in it! The guy at Honda sold me a
NGK DPR9Z in stead of the DPR8Z. He said that the DPR9Z plug will foul in the 400 the 8Z will burn hotter and keep it from fouling.

[trx400ex]

it says in the manual the 9 will work better for riding hard or something, doesnt it?

[TRFOXX]

Yes it dose, but its also a cooler plug which can result in
fouling. Dose anyone know for sure if that's the case? Thats
what the Honda dealer said. The dealer sold me that plug because I told him about my pipes turning blue and said i was running lean, but I did get a few long rides out of the plug.
I dont have any engine mods except 152 main jet, FMF Powercore
4 S/A, 4 1" Uni air vents, and Uni filter. Let me know if im missing something or you think i need to change something. Let you know that when it dose get started it runs great and has only fouled 1 plug so far. I didnt know if this was common or not?

[max400EX]

To me it kinda sounded like your valves. when my valves were bad, it ran like crap, backfired, and the plug was black.

The 9 spark plug is NOT your problem. The 9 runs hotter and is recommended for Fall and Winter use and the 8 plug dosen't run as hot and is recommended for Spring and Summer use. Mine was fouling out plugs regular and I had to change the jetting for it to run right but now it starts easily and runs great.