[jet_mech_tech]

Just wanted to post a quick comment that might help others out.
The bike: 2008 DL650 w ABS.

First the issue: Occasionally when i would be downshifting through the gears the bike would suddenly stall on me (usually 3rd or 2nd). Of course it would happen so fast that before i knew what was happening i would let the clutch back out, and jump start the bike back to life. This would sometimes happen when going around a corner (like turning onto a sidestreet) and cause a good wiggle on the rear as the rear tire skids for a second before restarting. Also, when i started the bike this spring it had what i thought was a bit more of a growl when i rolled on the throttle hard (didn't think too much on this as it had been months since i had started the bike due to the cold winter months here in Ontario and thought it was my imagination). But it was only occasionally and the rest of the time the bike ran like a top.

The solution: All too simple that i look back on it. When cleaning the air filter a month ago i noticed that the airbox had come off of the rear throttle body. Therefore the rear throttle body was sucking in unfiltered/non restricted air. Since the re-installation of the airbox not only does the bike not stall anymore but it runs noticably smoother and seems to have a bit more power.

Just wanted to post this as i'm not sure how often it happens but something so simple could definitely pose a big problem in the right circumstances (back end braking free, damaged engine) and thought it would be a quick check for someone.

 

[greywolf]

A massive vacuum leak like that creates an extreme lean condition. It makes a huge difference.

 

[dirtrider1]

I had a simular on my 06 Wee. I finally noticed that the idle speed had dropped way to low causing it to stall. Easy to adjust on the 06, all it took was a screwdriver and about two minutes.

 

[xDownSetx]

Very common with the 1000's, not so much with the 650's but it does happen. Another symptom would be the RPM's hanging a bit before coming down to idle.

 

[RichDesmond]

A massive vacuum leak like that creates an extreme lean condition. It makes a huge difference.

What he describes isn't really a vacuum leak (that's when the leak is on the engine side of the TB/carb) but more a case of just running unfiltered air into the engine and not having the benefits of the airbox. It was leaner than normal I'm sure, but not a whole lot.

 

[greywolf]

What he describes isn't really a vacuum leak (that's when the leak is on the engine side of the TB/carb) but more a case of just running unfiltered air into the engine and not having the benefits of the airbox. It was leaner than normal I'm sure, but not a whole lot.

Oops! My mind just went right to every other case of an intake separation I've ever heard of on a V-Strom, at the throttle body to engine connection. A separation on the airbox side of the throttle body would only lean out the mixture slightly but it would probably screw up the IAP sensor reading enough to cause an occasionally noticeable running condition. It wouldn't be dirt related.

 

[MikeB]

Interesting. At one point the airbox-TB connection came loose on my bike, and it caused the engine to race uncontrollably at start-up. Reconnected, it idled properly. I wonder why the OP's bike stalled and mine raced like crazy with the same condition. I just assumed the computer was throwing more gas in to make up for a perceived lean condition at the TB.