Results 1 to 9 of 9
  1. #1
    Join Date
    Sep 2006
    Location
    Arrington, TN
    Posts
    887
    Blog Entries
    2

    Default 250r Fouling Plugs at Idle

    My buddys 86 250r keeps fouling plugs at idle. As long as you're riding or moving, even at a slow pace it runs fine and will not foul the plug. If you let it idle more than a few minutes, it's toast. It's an unported 86 jug, standard bore with a wiseco piston, short rod crank, cool head w/ 21cc dome, atc head gasket, boyesen pro series reeds, fmf fatty pipe & silencer, keihin 35mm a/s carb-155 main, 48 pilot, needle in the middle, pilot screw 2 turns out. Stock air box w/a uni filter, lid off, amr coil, b8es plug gapped at .018". We just replaced the stator with a oe unit. He tried a b7es plug saturday and said it ran better than ever and didn't foul the plug. Should he keep running the b7es or drop the pilot jet to 45 or even a 42? I don't know what else to do to keep it from fouling plugs.
    01 Banshee....020" over, Pro Circuit pipes, DMC 916 silencer, CFM aluminum airbox,
    Uni filters, TDR reeds, lightened flywheel, milled head, +4 timing, Renthal bars,
    250r front shocks, Duro Hook ups on the front, Dunlop KT396's out back,
    400ex thumb throttle, TORS removed, yfz450 front brakes.

  2. #2
    Join Date
    Oct 2004
    Location
    pennsylvania
    Posts
    14,217

    Default

    i would not run that tight of plug gap on gasoline,what fuel and premix oil and what ratio whats an amr coil ? maybe its not getting good spark at low rpm and needs the plug cap trimmed back or this coil is not operating correctly
    CLICK BELOW FOR MY NEW SITE

    http://flotekperformance.com/home
    HELP SUPPORT OUR SITE >http://forums.everything2stroke.com/...ad.php?t=35928
    http://www.rjatv.com/
    cheapest ^^performance parts online

  3. #3
    Join Date
    Sep 2006
    Location
    Arrington, TN
    Posts
    887
    Blog Entries
    2

    Default

    Klotz super techniplate at 40:1 on 93. Amr makes aftermarket coils, cdi's and graphics kits. The old r ignitions aren't that great. They don't run with the plug gap opened up. It's got 185-190 psi last compression check.
    01 Banshee....020" over, Pro Circuit pipes, DMC 916 silencer, CFM aluminum airbox,
    Uni filters, TDR reeds, lightened flywheel, milled head, +4 timing, Renthal bars,
    250r front shocks, Duro Hook ups on the front, Dunlop KT396's out back,
    400ex thumb throttle, TORS removed, yfz450 front brakes.

  4. #4
    Join Date
    Sep 2007
    Location
    North Carolina
    Posts
    5,668

    Default

    I run the same plug gap on my 250R. I try to keep it .018 or .020, thats what ESR recommends. Maybe try dropping the pilot down a size or two. I'm not sure what your climate is or what elevation you're at, but running a 42 pilot may not be a bad idea.
    Support our site>> E2S Premium Membership

    E2S MOD

  5. #5
    Join Date
    Jun 2007
    Location
    MISSIPPI
    Posts
    694

    Default

    agree's with jared..... try bumping the pilot jet down one size at a time and see where that gets you. adjusting the pilot screw accordingly.
    250R's...... "they gots bite wiff dat bark !!!"
    R's are fo sand bars.....

    '86 TRX250R (265)
    '86 TRX250R (250)
    '86 TRX250R (CT310) WIP
    '86 TRX250R (WIP)
    '93 Blaster (WIP)

  6. #6
    Join Date
    May 2005
    Location
    Florida
    Posts
    815

    Default

    I'd recommend dropping the pilot one number and see what it does. 48 already sounds a little bit lean, but you never know. Have you ran a leak down test to ensure its not sucking trans fluid or anything?

    There really is no reason that the motor should need to run a heat range 7 plug. Honda recommends 9 series range and if it needs 2 more ranges hotter to run right something is up.
    www.everything2stroke.com
    www.3wheelerworld.com
    http://shop.3wheelerworld.com (Online store exclusively for three-wheeler parts)

    Rides:

    1986 ATC250R
    1985 Custom ATC500R
    1996 Full Laeger framed TRX250R
    2003 Yamaha GP1300R

  7. #7
    Join Date
    Sep 2006
    Location
    Arrington, TN
    Posts
    887
    Blog Entries
    2

    Default

    Yea we just rebuilt it a month ago...had to replace a busted left side crank half. I know the clymer manual says 86-87 came with a 48 pilot. 88 had a 45 and 89 had a 42. He's got a 45 ordered so we're gonna give it a shot. The bike runs strong...it can hang with my banshee for a short distance but the r does get better traction in the dirt.
    01 Banshee....020" over, Pro Circuit pipes, DMC 916 silencer, CFM aluminum airbox,
    Uni filters, TDR reeds, lightened flywheel, milled head, +4 timing, Renthal bars,
    250r front shocks, Duro Hook ups on the front, Dunlop KT396's out back,
    400ex thumb throttle, TORS removed, yfz450 front brakes.

  8. #8
    Join Date
    Sep 2007
    Location
    North Carolina
    Posts
    5,668

    Default

    I want to say that I'm running a 45 pilot in mine, but getting ready to drop to a 42 pilot. Not sure if it matters, but what type of plug are you running??
    Support our site>> E2S Premium Membership

    E2S MOD

  9. #9
    Join Date
    Sep 2006
    Location
    Arrington, TN
    Posts
    887
    Blog Entries
    2

    Default

    He had been running a b8es but went to a b7es...said it ran great and didn't foul the plug. We're still gonna drop the pilot jet down and go back to the b8es. I'm afraid the b7 is gonna be too hot and hurt the engine.
    01 Banshee....020" over, Pro Circuit pipes, DMC 916 silencer, CFM aluminum airbox,
    Uni filters, TDR reeds, lightened flywheel, milled head, +4 timing, Renthal bars,
    250r front shocks, Duro Hook ups on the front, Dunlop KT396's out back,
    400ex thumb throttle, TORS removed, yfz450 front brakes.