DR650 No Start - Stumped...

I’ve got a 2000 DR650 with 23k miles that I’ve owned for the last 4 years. I consider myself pretty capable mechanically (rebuilt/restored other bikes as well), but this problem has me stumped. Here’s what happened:

The bike was running normally, then sat for two months while I traveled (a friend was supposed to ride it, but oh well). I got back, put on some new brake pads and took it for a spin to bed-in the brakes. The bike was running well, I was having fun, and I sped up to 90mph on my way back home (it’s got a modified airbox, rejetted BST40 carb and GXSR exhaust…normally does 90 easy). All of a sudden the motor starts cutting out, I back off the gas and pull in the clutch, and the motor dies. Tried to start it again on the side of the road, no luck. When I try to start the bike, the starter motor cranks, the piston cycles, I have spark, but it will only fire for a millisecond and then die (maybe on just one stroke) after cranking for 4-5 seconds. Here’s what I’ve done so far:

- Did a leakdown test, looked great at 95%

- Changed oil, no metal shards found on magnetic drain plug or in pan

- Cleaned carb

- Drained old gas from tank, replaced with fresh gas and added fuel stabilizer

- Adjusted valves (they were a tiny bit loose)

- Replaced spark plugs (checked them on the bike, getting consistent bright blue sparks)

- Tested resistance of pulsar coil, power coil, and ignition coil (both primary and secondary) - all  within spec

- Battery tested and in good shape

After all this, I still have the same result when starting the bike. I haven’t tested the CDI box yet, but I think that’s the next thing on my list before tearing into the motor. Any ideas of where else to go from here? This really has me banging my head against the wall...

sounds to me carby related - getting fuel ?

diaphragm still ok ?

I'm thinking the same thing after going through the ignition system and having everything test to spec...the only other electrical/spark related thing that could be going wrong is the CDI. As for the carb, I inspected the diaphragm, but I wasn't exactly sure what to look for...there were no tears or any other obvious issue. Anything I should re-check?

Also, when I cleaned and reassembled the carb, the float assembly wasn't seating very well in the two openings where it sits in the carb body. I ordered a carb rebuild kit, so I can replace the float assembly o-rings and give it a shot. Should arrive in a couple days and then I'll install, will post an update.

Just a thought, but have you checked the little sock filter at the carb fuel line inlet? Having sat for a while crud can build up and block this. Also clean the idle and main jets.

Alright, did a full carb cleaning/rebuild today and even completely removed the filter at the carb inlet...same results. The next step is to check the CDI, so I'm on the hunt for a running DR near Ventura, CA to do a quick swap and see if mine's faulty. My only thought after that is there's something wrong inside the motor, either with the cam timing or maybe the piston arm, but I'm no expert here. Any other ideas are welcome.

 

FOUND IT. Took the stator side cover off the motor last night and confirmed a suspicion I'd had...a loose pulsar coil. The two screws holding the pulsar coil into the cover had backed out, which would cause the motor to fire briefly and then die since the coil would wobble out of position. In fact, one of the screws backed completely out and fell down into the motor, but luckily it had wedged itself at the bottom of the casing next to the crankcase oil separator plate. I was able to fish it out still intact. It appears that this screw must've fallen out VERY recently, because the damage to the pickup coil is minimal along with the screw. I had tried to start the bike yesterday morning during some tests and it was the first time I hadn't heard the bike fire even for just a moment...I'm guessing that was when it fell out. Last week, the pulsar coil tested within spec at 219 ohms last week, so I tested it again last night to make sure I wasn't crazy and now the reading is infinity (due to the damage from hitting the generator rotor). I've got a new pulsar coil coming from ProCycle and should be up and running sometime next week.

Seems like the big lesson here is that even if your pulsar coil passes the resistance test, it could be loose and consequently act like an intermittently failing coil. So check that before buying a new CDI. Thanks for all the help and suggestions, stoked to be riding again soon.

 

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wow, good job

Thanks for passing the information on.  Now us DR owners have one more thing we can check when it isn't working correctly.

What is it they always say?  "All you need to get an engine to run is proper fuel/mixture, compression, and spark".  The spark part has to happen at the correct time to be effective.

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