JOHNNI Posted October 5, 2005 Ha i have a 02 yz 250 and it foules plugs alot, last time just when i was warming it up but most of the time when i come down this hill buy my house were i ride. i always pull the cluch and rev it to keep it of idle and goose it on the non steep parts but after the hill ends and its flat ill get on it and bam foul. After the last time when i was warming it up i changed the plug and rode fo 20 minuts and the plug was black. This is all woods ridding, when i go to the track i dont foul. I checked the coil with a meter and the reading were not consistant with what the manule said and i order a new one but i want to check with you and get you oppinion. I ride between 6200 and 9000 feet 13 oz flywheel weight Needle Jet second clip form the top Float hight stock as per manual Needle Valve stock #50 as per manual Main jet 175 Piolt jet 48 Air screw stock 1 turn out as per manual, ive tryed it a couple of different places but still fouled Power jet #50 stock thanx Share this post Link to post Share on other sites
Kdmead Posted October 5, 2005 I think the reason you're not getting any replies is because your title says...2 Stroke Question Share this post Link to post Share on other sites
Sam_66 Posted October 5, 2005 Is your gas too rich? Share this post Link to post Share on other sites
Cozza Posted October 5, 2005 Is your gas too rich? Sounds like it. Share this post Link to post Share on other sites
Wayward Son Posted October 5, 2005 what is the stock main jet? Share this post Link to post Share on other sites
JOHNNI Posted October 6, 2005 178 i could i forget, 40:1 mix Share this post Link to post Share on other sites
ODH446 Posted October 7, 2005 The way it sounds your not mixing your gas to rich. Either it is your coil isn't hot enough or you need to run a heat range hotter spark plug. Share this post Link to post Share on other sites
Wayward Son Posted October 7, 2005 178 i could i forget, 40:1 mix your still much to rich on the main jet for sure. you canbe down a 165 main jet easily and probably more. looking thru my notes,i have several around set up with 158-162 mains at 5500-6000ft. Share this post Link to post Share on other sites
JOHNNI Posted October 7, 2005 thanx for the advice, im going to test the coil againe just to make sure than drop the main jet thanx Share this post Link to post Share on other sites
JOHNNI Posted October 7, 2005 thanx man going to test the coil agine and drop ther main jet to 165 thanx for you time Share this post Link to post Share on other sites
James_Dean Posted October 8, 2005 Turn the air screw outwards to lean the idle mixture, ~2 turns. You could easily use a #45 pilot jet instead of the #48. Your bike is probably loading up on the downhill and then fouling. The elevation will easily take leaner jetting across the board (between 6200 and 9000 feet ). Burned's main jet suggestion sounds about right too. James Share this post Link to post Share on other sites
mickeydee Posted October 9, 2005 ya,sounds like your mj is too big.i found on my old 94yz250 that if i went to rich i fouled and when to lean it would flaten out on top Share this post Link to post Share on other sites
