Ducati Monster Forum

Moto Board => Tech => Topic started by: chirrin on November 17, 2008, 11:43:35 PM

Title: how to regulate de air/fuel mixture if
Post by: chirrin on November 17, 2008, 11:43:35 PM
hey guys its me again i have a question how can i regulate the air/ fuel mixture if my carbs doesnt have those screws? my bike is 2000 ducati monster 750 and i have done research about the carbs and i have seen that other ones have those screws and mines dont  :o 
Title: Re: how to regulate de air/fuel mixture if
Post by: jerryz on November 18, 2008, 01:07:19 AM
The air screws are either under the little black rubber bungs are lead seals which can be prised out ..I know as I have a 2000 M750
Title: Re: how to regulate de air/fuel mixture if
Post by: ScottRNelson on November 20, 2008, 06:18:59 AM
Here's a photo of the carburetor from a 1997 M900.  Yours should look similar.  The brass screw on the left is the idle mixture screw.  It only affects the mixture from idle up to about 1/4 throttle and at low engine speeds.

(http://i25.photobucket.com/albums/c67/scottrnelson/Ducati/MikuniCarb.jpg)

If you're trying to adjust the mixture at larger throttle openings or at faster speeds, you need to remove the carburetor and either adjust the metering needle or change jets.  There are no external adjustments for those mixture settings.
Title: Re: how to regulate de air/fuel mixture if
Post by: dragonworld. on November 20, 2008, 03:05:48 PM
And if you find that this adjustment doesnt do squat about the gurgling/surging and general crappy small throttle opening performance it will most likely be the needle jets.  [thumbsup]

For some reason on the Duc these carbs wear these jets out fairly quickly. Not too expensive or difficult to replace. ;D
Title: Re: how to regulate de air/fuel mixture if
Post by: ScottRNelson on November 20, 2008, 03:41:41 PM
Quote from: dragonworld on November 20, 2008, 03:05:48 PM
And if you find that this adjustment doesnt do squat about the gurgling/surging and general crappy small throttle opening performance it will most likely be the needle jets.  [thumbsup]

For some reason on the Duc these carbs wear these jets out fairly quickly. Not too expensive or difficult to replace. ;D
Also known as the Emulsion Tubes.
Title: Re: how to regulate de air/fuel mixture if
Post by: chirrin on November 21, 2008, 12:35:41 AM
thank u for ur answer but the thing is that the picture that u show me has the screw, but mine has o close hole there is not even a hole! how did u do to put the picture so i can show u cause i cant put it thanks
Title: Re: how to regulate de air/fuel mixture if
Post by: Howie on November 21, 2008, 04:33:37 AM
Do you have stock Mikuni carbs as in the photo?  If so, they are there, but may be sealed, as described by jerryz.  As I said in the other post, I think you need local help.  Post here:
http://ducatimonsterforum.org/index.php?board=34.0 (http://ducatimonsterforum.org/index.php?board=34.0)
Title: Re: how to regulate de air/fuel mixture if
Post by: ScottRNelson on November 21, 2008, 07:59:03 AM
Quote from: chirrin on November 21, 2008, 12:35:41 AM
thank u for ur answer but the thing is that the picture that u show me has the screw, but mine has o close hole there is not even a hole! how did u do to put the picture so i can show u cause i cant put it thanks
On one of those carburetors as it comes from the Ducati factory, there is a brass plug over the screw.  I used a drill to remove the plugs from my carburetors, but I'm pretty sure they can be removed using a large sewing needle as well.

In any case, if your mixture problems are in the mid-range or at full throttle, you'll need to do more than just adjust those screws.
Title: Re: how to regulate de air/fuel mixture if
Post by: chirrin on November 21, 2008, 08:50:55 AM
ho thank u for ur answer i apreciate it,