94 DR250ES nearly dies on accelleration----sometimes

Hi all-

Have been through the archives but still need a bit of help trouble shooting this.  Just bought the bike.  It sat for 12 years.  Drained and cleaned the fuel tank, then filled the tank and let the new gas drain through the carb for several minutes.  Bike started right up, but would only idle with the choke halfway on, and might stall coming to a stop.  Pulled and cleaned the carb (I couldn't get the pilot jet out so I just sprayed carb cleaner and air through it.  Everything looked fine, but replaced what o-rings and gaskets I could.  Replaced carb and bike now idled great with choke fully open.  Now though the bike will hesitate and nearly die during accelleration, though not always.  In a twenty minute ride with moderate amounts of shifting, it might do this four times.  If when it happens I hold the clutch in and cycle the throttle, it will start running fine again and I can be on my way.  Archive searches pin point the following:  bad stand switch, bad run switch, loose CDI connectors, or air leak on one of the carb boots.  What about bad gas?


Sound to me like it's running out of gas. Did you pull/clean/replace the fuel filter and petcock? Also, if it sat for 12 years, you're going to need to go through that entire carb before it starts running right. 

Edited by Todd157k

I went for a ride yesterday after posting.  Bike started fine.  Did fine in first at low throttle getting off my property.  It then died as I pulled out onto pavement and accelerated.  I was going fast enough to bump start it, but it died immediately after starting.  I stopped and restarted it and took off.  It ran a little rough at first but then was fine for 2-3 minutes.  Stopped at a stop sign and it stumbled again on acceleration but did not stall.  Got it into fourth and opened the throttle almost fully open.  It ran fine opened up, and on the rest of the trip. maybe 20 minutes or so it only stumbed twice more, and only on acceleration, and it never died.  A few cranks on the throttle and it picked up and ran smooth.

These are my thoughts--if its having trouble getting fuel how come it runs fine with the throttle open?  Is the vacuum stronger on the diaphragm during acceleration?  If so, and the diaphragm has a small leak that might explain why it runs okay when you are not asking it to accelerate?

Thanks for your response Todd.


ya, it could be the diaphragm in the petcock has a leak. Put the petcock in PRIME if it has one, and run it. If it's ok, then it's the petcock. If not, it's carby. 

Edited by Todd157k

You Da Man!  Just got back from a ride with the petcock in the reserve position.  No problems, no stumbling, no stalls. 


Thanks a bunch!



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