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Old 07-08-2018
tone61 tone61 is offline
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JD jetting Wr250f

Just wondering what JD jet settings people have settled on. Bike is a 2013 WR250f. Tried recommended 185 main with red needle 4th clip and way too rich. Did oring mod and installed #60 leak jet supplied which has really improved initial throttle response and no bogging. Pilot circuit is ok ( 45 ) but needle and main settings are shit. Iíve heard using red needle 4th clip with stock 170 main is the go. Anyone found the sweet spot combo.
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Old 07-08-2018
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Nutty Nutty is offline
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No mention of the PAJ or MAJ you have fitted...you're wasting your time chasing fuel flow if the airs aren't done/correct. Get onto Thumpertalk, there's a WR jetting archive on there.
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Old 07-08-2018
tone61 tone61 is offline
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Quote:
Originally Posted by Nutty View Post
No mention of the PAJ or MAJ you have fitted...you're wasting your time chasing fuel flow if the airs aren't done/correct. Get onto Thumpertalk, there's a WR jetting archive on there.
Pretty sure I mentioned I fitted the 185 main and #60 leak as per instructions and the pilot circuit was fine with the standard 45 pilot jet and currently back to 170 main. Yep Iíll try Thumper talk and hopefully get the info I need.
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Old 07-08-2018
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Quote:
Originally Posted by tone61 View Post
Pretty sure I mentioned I fitted the 185 main and #60 leak as per instructions and the pilot circuit was fine with the standard 45 pilot jet and currently back to 170 main. Yep Iíll try Thumper talk and hopefully get the info I need.
The main (MJ), pilot (PJ) and leak (LJ) are all fuel jets. Your symptoms sound like incorrect air jetting (MAJ/PAJ). The fuel jetting swings off the air jetting.

JD kits are designed for US spec low RON/high MON fuels. I'd suggest using a OBEPQ or a OBELQ genuine YZ-F needle. I prefer the P if running YZ-F cam timing. Get yourself a Boyesen or R&D adjustable LJ as well. After a while you'll work out why...

Best air fuel sets are PJ45, PAJ 90 or PJ42, PAJ85
and. MJ170, MAJ185

There's 13 adjustments on a FCR, get them all correct and it will blow a FI bikes doors off.
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