New jetted XR650R

I just purchased a 2006 XR650R and I'm just in the finishing stages of dual sporting it. I've opened up the air box, done the jetting (175,68s,needle(B53E), and clip in the 4th position). Everything seems fine except when I snap the throttle from idle it bogs. When I roll on the throttle, even quickly it's fine. And this is when the bike is warmed up. I'm also at sea level.

Is this normal or is there something that I can do?

This bike is so much more fun than my old KLR650!

Any info would be greatly appreciated

Scotty, it sounds normal for the stock carb. What is happening when you snap the throttle is you are bumping more air into the intake faster than the jet is able to add extra fuel. The fuel-air mixture is therefore going lean for a split second and you get your "bog".

When you roll the throttle more normally the jet is able to keep up with the air flow.

Your jetting is fine, from your description. You have two choices: 1) understand and accept that snapping open the throttle on the stock carb will cause a momentary bog. Or, 2) if you have an extra couple hundred bucks replace the stock carb with a pumper carb like an Edlebrock Quicksilver/Performer.

With #2 you will get rid of 99.9% of the bog and you'll get rid of 99.9% of any flooding problems after a laydown. After I had my R for about a year it went this route. The throttle response is now close to an EFI system in smoothness and response time.

Lots of guys peacefully coexist with #1. Just learn to roll the throttle instead of snapping it open. Even with the stock Kiehin carb the 650R is a rip-snorter.

Either way you got yourself a sweet bike. Congrats, Scotty.

Ride safe.

Thanks for the very informative response.

I will probably just leave it alone as I can't really see when I'll snap on the throttle from idle position. As it is I can hit the throttle pretty hard without a problem and it starts very easily.

I put the Mikuni pumper setup on mine, and ooohhhhh is it sweet. Once its dialed in is pulls hard the whole way,, no matter how fast you twist on it. I did have to back off the throttle spring a notch to help keep the wrist happy. Never tried the Eldebrock, but heard lots of good things about them. The Eldebrock and the Mikuni are way easier to start after you lay it over. (Not that Ive ever laid my bike over:busted: )

Scotty,

One thing I noticed you said about your carb jetting is that you state 4th clip on the B53E needle. That is too rich. The B53E needle is supposed to be in the (3rd) middle clip position. That is most likely why the bogging is happening. The other info. from the other guys is great and true but I think the main problem at this point is the needles clip position. As it is right now, I am sure it is a bit lazy. Once you put it in the correct position it will clean up and have the power you are really looking for. Pumpers only make it even better but that could be for a future time when the funds permit.

That, my friend, is the infamous Honda "Dead-spot". It's a side effect from not having an accelerator pump carb. But honestly, will you ever be twisting the throttle that fast while riding?

The info about Clip position 3 on the needle is important. Also, are you running a cut-out side panel? That can cause bog by letting air rush in fast when you whack the throttle open. If none of that helps, you may want to try a 178 jet. I usually tune (leaving the carb on the bike) by increasing main jet size one-at-a-time until the bog disappears.

There is an air screw on the side of the carb. It sits above the float bowl on the right side of the bike. Verify that it is 1.5-2 turns out from screwed in (bottomed).

I had the Mikuni TM carb. It was great for midrange but sacrificed a little bit of power on top. I took it back to XRsOnly and the mechanic verified that it was slightly down on top end power compared to the stock carb.

Good luck.

When you ride, roll on the throttle instead of whacking it open.

If you did the airbox mod (extra holes), cover some holes with Ducktape and try.If it helps,you're too lean...And try a 70S pilot jet.

The side panels are not cut out. I moved the clip to the third position and didn't really make a difference. But I can live with it the way it is.

Thanks for your advice

Scotty905,

You do now have the B53E needle in the correct position,:censored: . But as has been mentioned also, the stock non-pumper carb cannot meter the correct fuel/air mixture when the throttle is snapped open quickly.

Besides this. 1) Did you be sure to pull out BOTH the rubber inlet boot & the plastic piece next to it from the airbox? 2) Did you replace the stock carb isolator (manifold) with the full internal diameter replacement part? 3) What did you do or what are you using as far as your muffler is concerned? This can make a difference. Sorry, I had to cover all the bases and ask, :ride:

The usual method of simply "drilling out" the stock tip does not come close to the flow of the HRC tip or aftermarket muffler, :lol: . This will effect what jets and settings needs to be used. If you are still using the stock muffler and stock drilled tip, there is still two internal baffles inside the muffler body that need to be bypassed. At the very least, cutting off the first baffle cap from the stock tip portion that resides within the muffler will get you closer to the proper flow. Even then it is not on par with what is needed to equal an HRC tip or aftermarket muffler. The second baffle cap which makes up the end of the spark arrestor section of the tip inside the muffler body, would need to be drilled out with a 1.5" holesaw and covered with screen. If you are not into modifying the stock tip that far and don't want to buy an aftermarket muffler, you can get a $40 freeflowing tip from ebay that should produce a similar result. Then, you could be effectively using the jetting you are currently running. If you use a HRC tip or aftermarket muffler than just ignore the exhaust info. I just gave, :applause: :applause:

Thanks Thumpage

I have a stock exhaust with the HRC exhaust tip, and the rubber boot and the plastic piece are remove from the airbox. The intake manifold is also been upgrade to the full diameter intake.

Then you are pretty much set. Sorry for rehashing things that you have already made sure to do. There just has been a few times where guys have skipped or overlooked some of the steps.

Be sure to properly adjust your pilot = fuel screw.

Holes in the sidecover can help the bike breath better also. :censored:

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