New XR650L exhaust upgrades & jetting

Hi guys I have a 2003 XR650L and like you all, I'm looking at upgrades. The pipe I'm thinking about going with is FMF PowerCore4 (not the Quite core) or the "Q" pipe. I'm in Maryland so I don't have to worry about the 96db issues / enforcement that most of you have to worry about in California (thank goodness). I also wanted to do the Jetting. I'm torn because Baja Designs has a $20.00 jet kit with drill bit that's been around for 5 years. (a lot of posts say that this kit was the way to go) But recently "BD" is recommending DynoJet's kit that has a needle,two main jets, a slow jet, and spring for $50.00. Is the new kit the way to go or should I go for older kit? From one prospective with the newer kit I can take it out (but I never will) if I had to, vs. the older kit that whould have been drilled out (no going back) Anyone out there in the same boat? What direction did you go in reguards to pipe and jetting?



I have a '01 XRL and started with the Baja kit then bought a new slide and went with the Dynojet. Dynojet was much better. Now I'm using a Qwiksilver Pumper carb with a Yosh Comp pipe & White Bros. oversize header. WHEELIE TIME! I was using a WB E-seris with the Dynojet. Are you planning on removing the air pump & airbox snorkle?

XRLMotard, I was contemplating going with a White Bros. E-series pipe. Just curious to hear your review of the pipe with the dyno kit and your jetting set up if your at sea level in VA. Also why you decided to go with the Yoshi pipe in comparison to WB. Was it because you motarded it and didn't have to be concerned with the noise level? TIA


I'll have to look at my notes to see what jet & needle position I used(been awhile). The E-seris is an awesome pipe, inifinitly tunable,etc. But when I started using it as a road bike only the rear fender started to melt! Even with the WB shield. (Prolonged cruising @ 80 MPH + !) The E-seris worked perfectly in dual sport mode though. The Yosh pipe has 2 smaller dia. inserts available to tone it down. I'm using the Comp. for a XR600. Works on the "L" just fine. I'll post the jetting when Ifind my notes.

Hey guys-

I recently upgraded my 2001 xr650l with the following: W/B E series pipe, Baja designs (Dyno jet) jets, spring, & needle kit, smog block off kit, removed the snorkel from the airbox and installed a Uni higher flowing air filter. The bike is a friggin' rocket compared to stock trim, the question I have is how many discs to run in the E series pipe ( I'm currently running 11, I removed 2 on advice from a friend)

I still get a little bit of hesitation off the bottom end when I hit it hard from idle or from decel. I'm looking to get the most snap.

Thanks for the help,


Thanks XRLMotard, That's exactly what I was looking for about the exhaust. I am very interested to find out if you used the stock pilot in the stock carb and which needle/clip position and how many disks in the E-series if your able to find it.

BLFD1, What needle, clip position, pilot and how many turns out on the fuel screw?

Found my notes. DJ 165 mainjet, 55 pilot jet, DJ needle 4RTH position(from top), stock carb spring, 3 turns out on fuel mixture screw, WB air filter, 12 discs on pipe(LOUD!) + 1 hard whack on throttle = BIG FUN! 14T/49T sprockets help. I used a 50T for awhile, almost pulls like a 650R. I went to the Qwiksilver carb because with the WB oversize header I would still get a bit of low end stumble, the pumper carb eliminates that. I think with the stock headpipe & a slip-on you can dial-in pretty close with the combo I used. Remember that the stock carb is a CV type(constant velocity) and there might always be some hesitation when you nail the throttle. I am at about 650 above sea level if that helps. Don't be afraid to try different needle positions & mixture screw settings to get your best performance. I never stop tweaking!


I've tweaked my jetting over and over. My understanding is that the low end sumble will never be eliminated on a CV (cosntant velocity) carb.. The reason for the stumble is that the carb only draws fuel as the air intake demands it. When you twist that thing at low rpm, the air volume is huge while the gas flow is still at idle. Once the air starts sucking more gas via vacuum, it will quickly catch back up, but unless you have a pumper you'll never get rid of the stumble. The best thing I have found is running my pilot just a hair lean and not overjetting the main. It's like putting a 600 cfm on a car instead of a 750. More response at low.

Good Luck

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