XR650L Big Gun Jetting

4 replies to this topic
  • rdsrf

Posted March 26, 2007 - 05:46 PM


I just bought a 2004 XR650L with a full Big Gun exhaust system with the quiet insert in. It doesn't run so great down low right now so I'm thinking it hasn't been jetted properly. Any jet kit and/or jet size recomendations? Mixture screw settings? Anyone know what the stock size main jet is? I'm down at sea level and humidity is 70-90%.

  • rebelventurer

Posted March 26, 2007 - 09:00 PM


I believe stock is 155. I am using the Dynojet kit which includes the 160, and 165 mains, new needle, as well as a lighter slide spring, around $50 for the kit. I am at sea level same humidity if not more have a FMF full system, K&N filter, desnorkelled and drilled air box, I am running the 165 main, with needle in 4th notch down and almost 3 turns out on air screw. You can save some $ by just buying the jets and doing daves mods.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • XR650L_Dave

Posted March 27, 2007 - 08:22 AM


Please note the dynojet jet#s do not correspond to keihin #s.

A DJ 160 is approx. a keihin 158.


  • 650_shark

Posted March 27, 2007 - 08:53 AM


I just did re-jet form a new exhaust system. I have the big gun header and WB E-series muffler. I am running a 158 main (actually I drilled my stock jet to 1/16" which is .0003" bigger) and 55 slow jet, also did Dave's mods(washer, drilled the slide) De-snorkled, de-smogged.

Stock jet is a 155 main, 52 slow.

Runs good, I had a little bit of popping on deccl but worked that out with the pilot screw I'm at approx. 2-1/4 turns. I would suggest starting with these numbers if you go the non-dynojet route.

  • goblin127

Posted March 27, 2007 - 11:19 AM


A 58/160 is what worked for me at about 150 ft/sea level.

Related Content


ignitech programmable XR650L CDI by brianhare

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • Hot  60 replies

Fell Off Trailer by usafxr

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

93 xr650l Restoration Project by Zigster

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

Supercross Preview 2017 Part 1: Championship Contenders by Chris Cooksey

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  186 replies

Wiseco 101MM Spark Knock Low Engine Temps by imandrewparks

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 9 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.