17 replies to this topic
  • rampaige

Posted March 27, 2008 - 10:56 AM


i got an 08 L and i have started uncorking it, but now it seems to be running very warm about 275 to 295 what gives, i have an xr's only temp dipstick, a 5.8 gal. fuel tank, racing exhaust and had pulled the air box snorckle but put it back still running warm.....what gives

  • Motosprtman

Posted March 27, 2008 - 11:15 AM


you say you have started uncorking it ... to what extent? the rejetting is the most significant part coupled with a good aftermarket exhaust so that the engine can breathe. The Dave's mods are most commonly done replacing the main jet with a 158 size main and a 55 pilot jet, the two holes in the slide are drilled to 5/32" and the tab on the air fuel screw is ground off and the screw adjusted to 2 1/4 turns out from bottomed. Also a small washer of .020 is installed under the head of the needle. You can also buy a dyno jet kit that will contain everything you need for the carb minus the pilot jet. I run the Dynojet kit in my 2005 XR650L and still installed a 55 pilot, makes it start ez and run better cold and improves low end throttle response. As a comparison I did just the Daves mods in the carb on my 93 XR650L and noted not much difference in either bike. The 93 seems to pull harder, but Ia ttribute that to the 15 / 48 gearing. Also, The air box lid (snorkle is removed) and a high flow air filter installed, such as a UNI air filter. A white borthers E-2 pipe or FMF Q2 are popular aftermarket pipe choices. The smog pump is eliminated and blocked off with an a kit available from IMS. With these mods the bike runs better and drivability is improved as the engine breathes better and gets sufficient fuel for combustion, still dependent upon where live and the ambient temparture these big singles can run hot. The tank wings DO affect coolng and most aftermarket tanks designed for the XRL retain that shape - somewhat.

Bottom line is dive in and get the jets replaced etc, then you will see a difference.

  • Bibleman

Posted March 27, 2008 - 11:24 AM


That sounds hot even for stock. Possibly a bad temp dipstick?:prof:

  • Motosprtman

Posted March 27, 2008 - 11:32 AM


if the stock jets remain - it sounds about right to me - and figure the engine is new and tight and that also generates some additional heat until fully broke in.

Bibleman is that really you in the pic in another post...

  • Bibleman

Posted March 27, 2008 - 11:35 AM


Ha! Yes, but I tell ya, I was just striking a pose!

  • martinfan30

Posted March 27, 2008 - 11:54 AM


DEFINATELY rejet with Daves Mods or a DJET kit.
By uncorking(as MS stated) you have made a lean running bike into a possible magnesium case fire.

Welcome to TT!

  • rampaige

Posted March 27, 2008 - 11:57 AM


thanks for th reply ...i thought that the aftermarkert fuel tank might be causing the problem but i am just curious that if the stock jets could cause such high temps.

  • martinfan30

Posted March 27, 2008 - 11:59 AM


thanks for th reply ...i thought that the aftermarkert fuel tank might be causing the problem but i am just curious that if the stock jets could cause such high temps.

Oh absolutely!
By making the exhaust free flowing, you NEED bigger jets for the extra fuel needed. Lean = heat.

Read here.
http://www.thumperta...ight=daves mods

  • rampaige

Posted March 27, 2008 - 12:06 PM


ok thanks ....what are some suggestions on jetting i an a novice and need the simplest jetting mod. there is...lol

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • martinfan30

Posted March 27, 2008 - 12:14 PM


ok thanks ....what are some suggestions on jetting i an a novice and need the simplest jetting mod. there is...lol

Simple is just paying 60 bucks for the DynoJet kit.

Cheap (not saying it is hard) is collecting a 158 main jet, 55 pilot jet, a .020" shim for the needle(I think thats the right size) and drilling the slide.

  • Motosprtman

Posted March 27, 2008 - 12:16 PM


you wana go here

http://www.4strokes....xr650lcarbmods/ print it out and follow it step by step you cannot go wrong.

to buy the jets you can go toyour local dealer and or http://www.jetsrus.com/main_page.htm and get a 55 pilot (slow jet) and a 158 main jet.

or for a jetting kit go to www.dynojet.com (about $50.00) and you still need the 55 pilot jet.

and come on back for more help if you need it. :-)

  • rampaige

Posted March 27, 2008 - 12:23 PM


ok thanks....are ther any pics of the dynojet mod

  • martinfan30

Posted March 27, 2008 - 12:44 PM


ok thanks....are ther any pics of the dynojet mod

Go here and click on the PDF for the xr650L.


  • Purcell69

Posted March 27, 2008 - 11:30 PM


The Dynojet kit is a pretty straight forward install. If you have already de-smogged the bike it is fairly easy to get to the carburetor. Remove the two 12mm bolts that hold the seat in place from the underside, ahead of the rear wheel, and the two side panels. Also remove the two 8mm bolts that hold the splash guard to the bottom of the airbox, ahaed of the rear wheel.

1. Take the three bolts out that hold the airbox in place (two on top and one on right near the rear brake MC.)

2. Turn your fuel "off" and remove your fuel line either at the carb or teh petcock.

3. Remove the two phillips head screws that hold the throttle cables to the carb right side of the body, then slip the cable ends out of the throttle on the carb.

4. Loosen the two clamps the hold the carb to the airbox and the intake and you should be able to slide the airbox back and to the left, partly out of the frame on the left side.

5. At this point you should be able to work the carb out the right side of the frame, disconnecting the bowl drain line and the vent line from the left side of the carb as you go.

6. With access to the top and bottom of the carb, remove the 4 screws that hold the top cover on the carb and remove the spring and diaphragm/slide assembly. Remove the white nylon widget from the slide with a phillips screw driver by pushing and turning CCW. With this out, you can remove the stock needle.

7. With the needle and widget out, drill the two outboard slide holes to 5/32" and then install the Dynojet needle and spacer, per the kit directions and reinstall the widget.

8. Flip the carb over and remove the 4 screws that hold the fuel bowl in place. Remove the fuel bowl and trim off the flange that stops the tab on the mixture screw.

9. With the carb upside down, the longer exposed brass jet is the Main jet. Install the appropriate Main jet from the kit. The brass jet inside the recess behind the Main jet is the Pilot jet. If you are going to install a 55 Pilot jet, install it now. Put the Nylon slosh guard back in place over the Main jet, (it will only fit one way,) and re-install the fuel bowl.

10. Reinstall the slide, making sure the needle is inserted into the main jet as it drops in. Be sure to align the corner port on the diaphragm with the port on the top of the carb body and install the spring from the kit.

11. Reinstall the carb cap, making sure to align it with the port at the corner of the diaphragm and the carb body.

12. Reinstall the carb, the drain and vent lines, fuel line, throttle cables and air box.

13. Reinstall the splash guard, side panels and seat.

I have done this twice now and it can be done in about an hour to 90 minutes. The process goes very well if the snorkle has been removed from the air box.


  • Motosprtman

Posted March 28, 2008 - 05:13 AM


If you deciude to use a Dynojet kit, install the 165 main jet that comes in the kit, as you are already running an aftermarket pipe.

  • rampaige

Posted March 28, 2008 - 06:13 AM


how much top end do you gain by jetting the carb.

  • Motosprtman

Posted March 28, 2008 - 06:38 AM


rejetting makes power better throughout the RPM range, Dynojet haa a graph that presents the overall gain. It also runs cooler.

  • Kenzo

Posted March 28, 2008 - 07:10 AM


i've uninstalled and installed my carb three times and never moved the airbox...just bend the rubber intake boot 90 degrees and it takes a little wiggleing to get the carb in and out...the choke fitting is soft plastic so be careful with it...i also replaced the carb top and bottom bowl screws with some quality fasteners

reguardless of gains...if you improve the airflow in and out of the engine(airbox & exhaust) IMHO u must rejet...these bike are lean from the get go and if you lean it additionally the heat caused will shorten the life of your engine significantly...heat and excessively high rpms are engine killers.

i replaced the PO installed Dynojet Kit with the proper pilot and main jets...shimmed the stock needle and drilled the slide...all for about $24 including shipping...this is in addition to de-snorkleing and a SuperTrapp race exhaust...the bike now runs like a scalded ape :prof:

using the Keihin jets i settled with the 55 pilot and 160 main(~165 DJ jet).


Related Content


93 xr650l Restoration Project by Zigster

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 17 replies

2015 XR650L Squeaking noise by Crayjay

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 3 replies

Which thumper motor for a street tracker? by woz

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • * * * * -
  • Hot  29 replies

Honda XR650L 2017 by Chris.GVS

Honda XR650L 2017
  • - - - - -
  • 0 reviews

Fell Off Trailer by usafxr

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • Hot  43 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.