XR650R lean on bottom, P.J P#'s?

9 replies to this topic
  • BCBrouwer

Posted April 21, 2007 - 09:36 AM


Hey there, My XR650R runs as strong as ever, but I did a few changes this past winter. I opened up the side airbox cover. I also have a uni filter/W/no backfire screen, All uncorking upgrades with the honda racing baffle too. Im running 68s pilot, screw 3.25 turns out, b3 needle, 3rd notch (runs better than 4th notch), and 182mj. 0-1000" elevation. Just a bit lean on the bottom, hanging idle, popping on decel (more than before I made more air available) Long story yes, but you guys may have other suggestions before replacing the pilot (prob not though) Anyone have the part number for a 70s pilot jet? I know 3.25 is too much on the screw, and it wants more. 70s would work better yes? Thanks a bunch for any honest input.

  • needsprayer

Posted April 21, 2007 - 10:08 AM



182 MJ is large - what does your plug look like?

Conventional wisdom says: If you see an improvement with the air screw more than 3 turns out you need a smaller pilot jet - try a 65

A little popping is normal

Hanging idle - possible air leak - check carburetor clamps for fit & tightness

  • drop

Posted April 21, 2007 - 02:03 PM


What's the temperature in Nova Scotia now? Probably pretty cold yes?

  • needsprayer

Posted April 21, 2007 - 02:46 PM


Good point DROP.

Let's see then.

Halifax, Nova Scotia

High today at 1400 18 C 64 F
14 day trend, Highs above 12 C 53 F

Recommended jetting: 178-180 MJ (w/ Side Panel cutout)

So 182 MJ is much closer than I thought. I sit corrected.

  • drop

Posted April 21, 2007 - 03:49 PM


Yeah 182 is only slightly high for him or most of Canada in all but the middle of summer. I'd try the 70s. Sorry, that's not what you wanted to hear. I'm going to try 180 main, 70s pilot on my bike for Ontario. It doesn't have the side panel cut but it does have a Jardine full exhaust, unifilter, and uncorked of course. Your bike with stock header and hrc tip (i'm assuming that's what you have) would probably do well with 180/70s also. You can find the 70s part number by doing a search on this forum.

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  • Thumpage

Posted April 24, 2007 - 07:57 PM



Conventional wisdom says: If you see an improvement with the air screw more than 3 turns out you need a smaller pilot jet - try a 65

A little popping is normal

Hanging idle - possible air leak - check carburetor clamps for fit & tightness

Sorry, but the pilot screw quote is all wrong. The pilot screw is a fuel screw not a air screw. A fuel screw and air screw are tuned exactly opposite. Two stroke carbs have air screws & 4 stroke carbs have fuel screws.
If someone is more than two turns out on a fuel screw to get the bike to run and idle properly, the pilot jet is too small. Therefore, you would need to go to a bigger pilot jet.

Besides that, I do agree that an air leak at the carb isolator boot can also cause a hanging idle similar to lean jetting.

  • needsprayer

Posted April 25, 2007 - 09:26 AM


Well there you go, I'm mixing apples and oranges. I ride the CR250R more lately and recently changed jetting on it.

Sorry for the mix-up.


  • captb

Posted April 25, 2007 - 03:32 PM


I run a 75 pilot, idle fuel screew 2 turns out, I have to go in 1 turn to pass emissions. Starts first kick, solid idle, runs cool, no hesitation, no popping on decel, spark plug is 4 years old, don't know what it looks like but it allways runs good so I don't mess with it. I do have a UniFilter, side cover cut out and a Powerbomb with WB R-4 silencer :applause: allthough it don't do alot of silencing.

  • bigtooth

Posted April 26, 2007 - 05:13 AM


When you guys say popping on decel, do you mean slowly throttling down, or cruising down a hill and completley closing the throttle? Just trying to get an idea of what my bike should be doing.

And to add the little jetting experience I have with my 650, i'm running:

b3 needle 3rd notch

I'm in vermont and have the stock tip completely cored out and covered with a screen, an UNI filter and of course uncorked.

Before I cored the tip it was just drilled out and it seemed to be running a bit rich.

  • needsprayer

Posted April 26, 2007 - 06:49 AM


Rolling off the throttle, I.E. going from 3/4+ to 1/4 throttle quickly, but not abruptly closing it all the way. I get a gentle series of pops, not loud or harsh.

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