DR 650 chokes, then backfires

[the ruffian]

So, over the last few weeks I have this randomly occurring problem: I’ll be cruising along ( like quarter to a third throttle, on open road) when suddenly , and for no more than a second or two, the bike chokes and dies, and then with a single loud backfire, resumes the cruise.

It seems completely random. On a recent trip , which included the Baviaanskloof, it didn’t do it for a coupla hundred Kay’s, and then close to home it did it three times in a hundred Kays...?!

Can it be dirt in the carb? If so, why doesn’t it affect starting , and the otherwise smooth running that the bike exudes?

Looking forward to your analysis.

With thanks...

[katana]

Check the spark plug, cap, lead, kill switch, ignition switch, side stand switch.  Unlikely you have a fuel issue as unburnt fuel is filling your exhaust.

[katana]

Maybe CDI or wiring.  Long story short, probably electrical.

[chopperpilot]

DRs are very reliable.

I agree on Katana's analysis, but would first tick the carb off the list, as its relatively easy to remove, strip and clean, although the symtoms might not indicate a fuel problem.

[the ruffian]

Good tips, all.

Thank you, K , and Ch.

I’ll let you know what transpires...

[Colin Kaapschehoop]

Check that you haven’t got water in your tank.

[the ruffian]

What’s the best way to do that ,Colin?

[katana]

Put a hose on the carb drain and drain the float bowl into a glass.  Any water will float in the bottom - easiest way too check..

[lecap]

My money is on the side stand switch. Check and lubricate the side stand pivot.

[the ruffian]

Would you consider de-activating the side stand switch?

[the ruffian]

So, here’s the update:

For 2000ks after the original post I did all the wiring and carb checks (thanks for the suggestions, Oakes!), but the problem persisted, very randomly.

Then , timeously (with a big trip coming up), LeCap weighed in with his assertion that it was the side-stand. Thank you, Jurgen! I disassembled the unit (in the up position it was rubbing against the swing arm) bent the shaft accordingly, re-tensioned the springs , lubricated everything , including the switch, and voila! Just did a 3000k trip with no problem. Rode with Ri, who owns several DR650’s, none of which have a side-stand switch - for all the obvious reasons.

Oh, and just for the record, my bike has 25k on the clock, and on this 3000k trip (Northen Cape/Boesmanland...2500ks on dirt), not a drop of oil used, no chain adjustment needed, best consumption 26km/l and average consumption overall 23km/l. That’s carrying quite a load (self-supported for 10 days with full winter rig and camping gear). Look out for Ri’s RR soon...

[Ganjora]

nothing to worry about with a DR until it decides to eat its own gears and destroy its entire engine.
yes,  the ENTIRE engine.
great bikes,  and nothing to complain about,  up to THAT point.
 

[Ri]

nothing to worry about with a DR until it decides to eat its own gears and destroy its entire engine.
yes,  the ENTIRE engine.
great bikes,  and nothing to complain about,  up to THAT point.
 

And then goes strong for another 10 years after. I think yours is the only DR 650 in RSA this has ever happened to 

[Jacobsroodt]

An intermittent starting problem on a CRF230F that I could not trace was eventually identified as a wire running to the start button via the neck that had gone brittle and made occasional contact. I found that out by pressing the start button and then rotating the handlebars until the starter suddenly started turning.  Might be an electrical issue, given the age of the bike?
my 2c

[Ganjora]

And then goes strong for another 10 years after. I think yours is the only DR 650 in RSA this has ever happened to 

that's why,  once a bike is out of manufacturer's guarantee,  only Runner can touch them.

most likely the only on WD.
i know you love them,  and i know you love our one especially,  but not for me.