YZ250 woods riding

[yama426rider]

My brother has a YZ250 that if he rides it in the woods or on my tight 4stroke practice track will almost always foul a plug after about 10 - 45 mins sometimes longer or shorter. If you are able to ride the bike way fast all the time its fine. My question is how would we go about making this thing better for tight slow woods riding and still be able to do some fast riding as well?

[dirtrider1]

The short answer is to jet it correctly, I ride my 250 100% woods only, and have never fouled a plug. My jetting isn't perfect, but its close and I'm striving to get it better.

[Brumy 55]

That must be nice because i know excactly what yama 426 is talking about because i have the same problem with mine

[mattskn]

The short answer is to jet it correctly, I ride my 250 100% woods only, and have never fouled a plug. .

Same here I can go all day in first and second and not foul a plug.

[Brumy 55]

How do you have your bike jetted because fouling is a big problem with my bike

[tonybalony]

what gas/oil ratio do you run?

[odonnks]

I run 32:1. Never fouled a plug yet. Its in the jetting.

What year YZ?

Also, Check out the jetting sticky at the top of this forum.

[yama426rider]

Its a 99 yz250 if we ride a full day in the woods he will probably foul 4 or 5 plugs

[mattskn]

I am between 400-600 ft above sea level and I run 168 main and 48 pilot air screw 1 1/4 turn to 1 3/4 turn and dont have any problem with fouling plugs.Give it a try Make sure you read your plug after a quick ride and check color:thumbsup:

And I mix my gas 40to1 I use maxima super m

[kawamaha]

when I ride on small tracks or woods I put a NGK BR7ES plug in. this thing should be about 3$ and almost no work. I would try it first

[yama426rider]

Thats what he has been running

thanks

[kawamaha]

Thats what he has been running

thanks

he run a "7" spark plug with a jetting that seemed ok? I hope for him he is cleaning the air filter regularly (a dirty filter causes a richer mixture) so that sounds like a real problem

[huey104]

I'd try running your fuel 50:1, use 93 octane (premium) and Bel Ray H1R. Never fouled a plug that way. Just adjust screw to run right not to rich, not to lean.