jetting, mpg, @ 7000' plus

8 replies to this topic
  • Flagstaff

Posted May 08, 2009 - 08:47 PM


I recently bought a 06 wr450 stock, but with poor maintance (dirtyoil, hole in air filter). After short testride tore down top end, mic'd everything, everything in mid to tight end of specs. 1 tight valve, no leaks with valve gas leak test. Same time rejetted JD red needle 5th from top, 165 main, 165 starter (stock), gytr 48 pilot, stock 50 leak, zip ty fuel screw 1.5 turns out,JD thick o-ring. Runs somewhat better than my drz400 kicker, handles better, but i'm only getting 25-30 mpg on forest service roads 10-50mph. The drz got 45-50 similar riding. Ride 7-10k ft. Forgot, did greywire, airbox snorkel and cutouts, peashooter removal. Plug is black. Do i have a jetting issue or is this normal? Would live with it, but the black plug tells me I'm rich ? And it feels rich. Thanks, searched with my limited skills and better than half way through a 12-pack, couldn't find an answer.

  • ww44wrf450f

Posted May 09, 2009 - 03:42 AM


  • WR_Dave

Posted May 09, 2009 - 05:16 AM


I would say that your pilot jet is waaaay tooo big. I ride at some of the same altitiudes and am using a 40 pilot. The 165 main should be OK, but it's easy on that bike to experiment with a smaler MJ. If your DRZ is basically stock it is jetted ridiculously lean. I opened up a friends DRZ and his power and fun went up and the mileage came back to where the WR is. WR's are hotrods not smart cars when it comes to the fuel mileage department. WR Dave.

  • Flagstaff

Posted May 09, 2009 - 08:46 AM


Thanks WW44WRF450F and WR Dave, looks like mpg is not unusual for these bikes, will need to get a bigger tank.

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  • Chas_M

Posted May 09, 2009 - 11:10 AM


At high elevations, even with the JD red needle, you will need to run it leaner than the 5th clip.


Posted May 09, 2009 - 01:35 PM


If I read it correctly you're 5th from top on the red needle. You should be 5th from the bottom so you are at least 2 clips too rich right now. That is probably 99% of your problem. Your main is a little rich but not bad. I'd probably put a 162 in it. For the pilot a 45 or 42 would probably be better as well. Plug color is not really a good indicator on these bikes so don't worry about that too much. If you lean the pilot down too much the bike will start popping out the exhaust on deceleration. As for mpg cruising on dirt roads/jeep trails I get in the mid 30's but pushing it hard will drop it down into the mid 20's. From the riding you're describing I would guess your mileage will improve a bit once you lean it down.

  • Flagstaff

Posted May 09, 2009 - 08:08 PM


5th from TOP per JD and elsewhere on these forums. Think I'll try 145 pilot, 4th from top 162 main. Dirtbike tested an 09 here last fall and liked stock jetting.


Posted May 10, 2009 - 06:23 AM


5th from TOP per JD and elsewhere on these forums. Think I'll try 145 pilot, 4th from top 162 main. Dirtbike tested an 09 here last fall and liked stock jetting.

My JD kit sheet say 4th from the top 6000' - 9000' and 3rd from the top above 9000'. I think your settings will work fine.

  • Flagstaff

Posted May 10, 2009 - 08:05 AM


Thanks PBDBLUE, hope to try it today


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