Mods for 2003 650L?


I am new to TT but must say am impressed with the wealth of knowledge here. I have been looking around a fair amount and have some ideas about what I should be doing to modify my bike but don’t have the experience I need. I am picking up a 2003 650L that is stock and need help with mods. I want to get the most out of it but am unsure where to begin. I know I need to jet it, change sprockets, new exhaust…. and so on but I am not sure where to start and where to finish. I would really appreciate any outline or help I can get regarding mods that will help me get the most out of it.



Do a search on this forum. They have been posted many times. Look for posts by XR650l Dave if it can be done to the L hes tried 2X.

Hey Jlp - I have been reading to some degree but will keep diging. I was wondering if they all needed to be done at once/in order or if I can make changes over a few weeks to help the pocket? I'll keep reading. Thanks!!

Do the jetting first!!!!!The bike is jetted very lean to start with and doing the other mods before hand just makes it worse. After the jetting you can take your time with the mods good luck and enjoy. I love mine.

Alos do a search in the dual sport forum and look for post by Tourture Chambers to see what the bike is capable of in skilled hands. It will blow you away.

Good choice on bikes, :naughty: I love mine. I would do the exhaust. I have the White bros E series. Remove the snorkell, add a uni filter, and remove the smog and then jet. Also going down to a 14 tooth on the front works awesome for off road. Look on four for instructions on smog and snorkell removal, its very easy. Good luck, and happy trails. :naughty:

Take the carb off, drill the two vacuum holes on bottom of slide to 5/32, shim the needle up .024 with a small washer (radioshack). Re-jet to a 158 -165 main and a slightly larger pilot jet (depends on elevation). Install a K&N or Uni filter. Remove the smog equipment. Remove the snorkel under the seat on top off the air box ( drill the rivets out). Install a good free flowing exhaust ( yoshimura, big gun, WB, FMF). Re-gear the front and rear to 14/48 or 15/48. And if you really want to have some fun you could install a stage 1 Hotcam camshaft. Also a larger tank will ease you big thumpers thirst a little.

All of this will increase Horsepower and throttle response. It will actually transform the XR 650 L into a good working on and off road bike. I take mine EVERYWHERE. The trails here are very rough and the things performs good.

I bought a stock 03 that was basically new at 600mi. First mod was smog removal with IMS kit. Next was billet rear shark fin disc guard and Acerbis fork guards w/disc cover.

current mods in progress hopefully done this weekend. Summers bros fork guards and seal savers and billet fork stabalizer. White bros E-series pipe and jetting and Uni filter.

Next will be a Clark tank and some new bars with Acerbis rally guards and extensions for the wind.

Very cool, thanks for the input!!!! It has around 2000 miles which have mostly been on the road. I am hoping to pick it up this weekend and will start with the mods during the week. I'll f/u with my thoughts after mods are done. I think I am going to start with jetting , exhaust, smog equipment and then finish off with the gearing.

Thanks for your thoughts, really appreciated!!!!!!

Wheels, where are you in NB? I lived in Edmundston for many years, went to UNB in Fredricton. Currently on Canadian boarder in Maine.

WOw lot of maine members in this thread. thanks MrGraham i had the same questions this thread was alot of help

650L stock BRP

Hey char!

Picked up the beast last week! Runs very well but is a bit flat and boggy when I snap the throttle and spits when I down shift. The bike is still stock but I will be starting on the mods in the next couple of weeks! A question for anyone who has changed the front sprocket from a 15 to a 14 tooth, how is the top end? I will be running about 50-50 road and dirt.


I went from stock gearing to a Teraflex and 14/48 Sunstars...

Lost like 10 mph on highway top end

so you gotta decide what you need more!

I am from Musquash ,NB. It's 35 minutes from St.Stevens.

stock, you should be able to pull 99mph, by most accounts ... the 14/48 should bring you down to about 85 or better, but my front end gets pretty light over 80-85mph, anyway ... hope that helps

I am going to go to a 14 on the front, any reccomendations? Got most of the things needed for mods, just waiting on the pipe. Thanks for the feedback!!!

Happy Trails

Just got most mods done, seems to have awaken the beast!!! I'll know more this weekend!!! Thanks for the info.

And the AAV army grows by one more...


I tried to order the E series white bros. and i was told it was discontinued. Had found a real good price too. Is the supper trapp the same system,the price seemed resonable?

If you really want to get into it, call up thumper racing and order there 675cc BBK and the hotcams stage 1 cam! You wont regret it at all, good luck!


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