XR650L Fuel Screw...

4 replies to this topic
  • MotoMike14

Posted November 21, 2004 - 03:26 PM


My dad just picked up a 2005 650L, and he's been fiddiling with the fuel screw to get it right. We've got it close, but what does everyone else run? Thanks

  • XR650L_Dave

Posted November 22, 2004 - 09:41 AM


2-1/2 turns is about right when the correct pilot jet is used. From the factory, its too lean.
So he ground off the tab? It might run better 3 turns out or so, but after that it doesn't really make a difference.
On this bike, there is a no-fail 'formula' to get a lot more oomph with minimal $$.

1) do not, Do Not, DO NOT buy a dyno-jet, K&N, or Baja Designs jetting kit for it. Its a $35-$50 waste of money. It works better than stock, but not nearly as good as the 'recipe'.

2) Remove the slide from the carb and remove the needle from the slide

3) Drill the 2 off-center holes in the slide to 5/32 of an inch (the 2 holes not for the needle).

4) Re-install the needle, but put a 0.030 inch washer under it. Make sure the washer fits into the little 'well' at the bottom of the slide

5) File the tab off the float bowl that keeps you from spinning the pilot mixture screw.

6) Jet with a 55 pilot (get the short one) and with a 158 main. (this is sometimes a tad rich with the stock exhaust and the other mods listed here). Here in CT they're running gasohol so I had to go richer.

7) Pull ther snorkel (as suggested many times over)

8) Get a better air filter. I'm running the K&N, they say they're prone to letting dust through. UNI makes a foam filter.

9) there's a little more airflow to be had by making an easier path to the top of the airbox (its really restrictive under there).

These mods improve the throttle response enormously, and improve the driveability. The bike is so lean stock, that rejetting IS normal maintenance.

Good Luck,


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  • MotoMike14

Posted November 23, 2004 - 04:11 PM


2 1/2 sounds about where we have it. Any other recommendation for just rideability, and not performance wise. No problem with performance, just trying to smooth out the edges.

  • yooper_porkchop

Posted November 23, 2004 - 05:24 PM


I did the screw thing somewhere around 2 1/2 and a UNI air filter, cut down on a lot of farting in the exhaust. Are you riding street mostly or off road, I use mine mostly on 2 tracks and gravel roads with some single track, I found that going to a 14 tooth front sprocket made a world of difference off road for me, next time I replace sprockets I will also change the rear from a 45 to a 48 tooth along with the 14 front. This gears it down and makes it better in the woods as far as I am concerned.

  • XR650L_Dave

Posted November 24, 2004 - 09:11 AM


MotoMike, the mods described do wonders for the rideability and throttle response.


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