Ducati Monster Forum

Moto Board => Tech => Topic started by: austin6728 on October 25, 2011, 05:07:56 PM

Title: Carb/ Fuel problem
Post by: austin6728 on October 25, 2011, 05:07:56 PM
My 2001 Ducati M750 has recently developed a problem. The biker starts great rides great but more and more often when i come to a stop after riding the bike it will idle at 1400rpm and all by itself the revs will pick up to 2500 rpm sometimes if i give it i quick blip of the throttle it will then return to the 1400 rpm but seldom. Sees like an issue with the carb i think but would appreciate any input anyone has

Austin
Title: Re: Carb/ Fuel problem
Post by: hillbillypolack on October 25, 2011, 05:45:04 PM
 [popcorn]

I'm listening too.
Title: Re: Carb/ Fuel problem
Post by: the_Journeyman on October 25, 2011, 07:00:18 PM
Sounds like a vacuum leak.

Check the runners from the carb to the cylinders.

JM
Title: Re: Carb/ Fuel problem
Post by: Howie on October 26, 2011, 04:14:19 AM
Turn the idle down to 11-1200 RPM.  When the ignition module sees 1400 RPM+ a bit the ignition advance kicks in.
Title: Re: Carb/ Fuel problem
Post by: Autostrada Pilot on October 26, 2011, 07:51:46 AM
Quote from: howie on October 26, 2011, 04:14:19 AM
Turn the idle down to 11-1200 RPM.  When the ignition module sees 1400 RPM+ a bit the ignition advance kicks in.

+1

My '99 900 did the same thing, and once I turned the idle down a hair, it fixed the problem.
Title: Re: Carb/ Fuel problem
Post by: hillbillypolack on October 26, 2011, 04:16:46 PM
Here's the thing.  I lowered the idle, which was like a kitten in the driveway.  Checked the intake runners with brake fluid spray (you'd hear it accelerate if there was a leak).  No leak I could detect.

So, it idled fine in the driveway, but 3 miles away from home it's idling at 2300 at the first stop light.  I'm currently in the process of doing the Ignitech and FCRs.  I'm wondering if I was stupid not to fix the issue before the upgrades.
Title: Re: Carb/ Fuel problem
Post by: koko64 on October 26, 2011, 04:57:02 PM
A lean idle mixture can cause the idle rpm to "hang up", as can a manifold leak. Sticky cables can do it. Adjusting the idle speed before its fully warmed up can cause the problem also.
Fit the FCRs and see what happens. Chances are its a carb problem.
Re the Igniteck, you have stock pistons?
Title: Re: Carb/ Fuel problem
Post by: hillbillypolack on October 26, 2011, 07:07:07 PM
Running JE high comp with stock bores.  It's a bit trick, so I have a little testing to do.
Title: Re: Carb/ Fuel problem
Post by: MongoReturns on October 26, 2011, 07:32:16 PM
Mine's been doing this, FOR 10 YEARS  [laugh]  If it bugs me or hangs for too long, I blip the choke & it goes to normal.  It did it more until I adjusted the idle screw, like 7 years ago.  I always figured it was ovaled emulsion tubes or something else I didn't want to mess with.
Title: Re: Carb/ Fuel problem
Post by: koko64 on October 26, 2011, 07:58:10 PM
Quote from: hillbillypolack on October 26, 2011, 07:07:07 PM
Running JE high comp with stock bores.  It's a bit trick, so I have a little testing to do.

I have the same, FCR 41s, JEs, bit of porting, Igniteck.
Let me know if you want some starting numbers for your advance curve. A few of us have set custom maps with the Igniteck. Check out Brad Blacks Bikeboy site re igniteck.

If you fit the FCRs you can at least check out the manifolds for internal cracks, etc.
Title: Re: Carb/ Fuel problem
Post by: austin6728 on November 08, 2011, 07:35:24 PM
Quote from: howie on October 26, 2011, 04:14:19 AM
Turn the idle down to 11-1200 RPM.  When the ignition module sees 1400 RPM+ a bit the ignition advance kicks in.

  :) :) :) Thanks howie that semes to have worked for me
Title: Re: Carb/ Fuel problem
Post by: austin6728 on November 10, 2011, 08:55:31 PM
Quote from: Autostrada Pilot on October 26, 2011, 07:51:46 AM
+1

My '99 900 did the same thing, and once I turned the idle down a hair, it fixed the problem.

Thanks for that bike running great now