bombrider04,

I'm no carb expert by any stretch but I do know that the only "adustable" jet is at the very bottom of the carb nearest the engine. There is an open hole on the bottom of your carb and it takes a medium-small flat screwdriver. This is the one you adjust (discounting the idle adjustment ****) while the engine is running...screw it in/righty/clockwise closes the orifice and lefty/counterclockwise opens it up. You are supposed to close it while the engine is running until the engine stumbles and then open it until the engine stumbles and then put it between those two points and rejet the main or adjust your needle if you get no stumble which will require more research as to what that means. This is your air adjustment screw, I believe, and it is the one that the pipe companies suggest you turn out two turns. Basically that means take it all the way to seat and then screw out two full turns...hope that helps a little.

Jim

 

Thanks jiminok I appreciate the response and when I get home I will check it out and if I have any ?'s I will let you knwo and it isn't inside the bowl because thats what I got confused with.

 

Alright so when I got home I took a look at the carb to see what I was messing up and it was alot and realized how dumb I was correct me if I am wrong...All Of the jets get snugged up and jet the carb depending on lean etc and where to set the needle...Then once you have those in you need to take the adjuster in the back of the carb engine side which is recessed up in the hole turn it as jiminok said...I never knew about the screw at the bottom of the bowl and it will things alot easier now...The only thing that I want to know is what those 2 jets do in the mouth of the carb which are on the sides, but thank you very much jiminok because I have been having troubles trying to figureing the carb out and it seems to have cleared things up and this is the one which omr said to drill and put a **** to turn by hand that way it is easier to adjust correct...Thanks again.

 

This is from the beginning of this post.

Lets review why the stock carb runs lean at high rpm's with lid off:

The factory built the DS to meet emission and speed regulations.
For many years all builders hated cv carbs because they needed negative pressure created by a closed air box to help slide and fuel control in the carb.

So how do we out smart all the above.
First, improve the exhaust system.
Second, rebalance the carb to match the motor needs - stock carb mods.
Third, control the negative pressure inside the carb, not in the airbox. - this is new.
Air going threw the venturi generates negative pressure, slide rises and fuel is drawn up the needle jet. Before fuel can rise quickly it needs to be atomized, thus the emulsion tube adds air to the fuel. Where does the air come from, threw the air jet on the right front of carb air intake. Side where throttle cable is mounted. Other side jet is for the pilot jet system.
But what happens when you allow outside air to enter the venturi area of a carb that has not been threw a tapered orifice?
It now becomes a air bleed. It now reduces the negative pressure in the venturi and has rpm's rise it starts to lose its ability to draw fuel up fast enough to match the air requirements. Fuel mixture starts to run lean.
The air bleeds control the mixture mostly at mid to high rpm. The air bleeds are best described as a controlled air leak in the main circuit. The air bleeds work by "bleeding off" this vacuum, which draws fuel through the main jets. A larger air bleed will make the mixture leaner at high rpm by bleeding off more vacuum or "signal."
How do we adjust for this condition? Install a smaller air bleed to richen the high rpm mixture by bleeding off less signal.

The fix:
The main air jet in the DS is a number 120.
The main air jet in a Quest or Traxter is a number 40
Part number 707200187
120 is actually a .037" hole.
40 is a .022" hole

The 40 still supplies all the air needs for the emulsion tube, but maintains the negative pressure to supply the needed fuel for high rpm's with the lid off.
For times that we are riding with the lid-on, jet accordingly, but there is added power at high rpm's also.

With the air snorkel removed from the front of carb, when looking straight into the carb venturi, the air jet is at the 3 o'clock position. Same side as the throttle cable. You will need a small screwdriver to remove the jet. Cost is around $8.00
When reinstalling, do not overtighten, small threads.
This will richen the mainjet by about 2 jet sizes and not allow the top end to lean out.

Note: To run with the lid off, remove the gasket also and if the 3 rubber clamps are loose, remove them also.

This tells you what those jets are in the mouth of the carb. HTH

 

I have a 04 DS and today decided to do this mod. I called my local dealer to order the 05 spring. He tells me the factory only sells one spring. Would I be correct in assuming that this spring will be to the 05 specs OMR wrote about????

 

I would think so. After 03 they started making the shorter springs! Maybe they only sell the new ones now b/c they figured out the long ones wouldn't cut the cake?!?!?!! But yeah, I think you would be safe to assume that! Just tell them you need to know how long the spring is before you order it. They should be able to at least find that out!

 

I got my new spring today. When I pulled the old one it was the same length. I went ahead and changed them anyway. The old one felt softer than the new one. Did not have the same stiffness. Was this a good decision???

 

I think you want the softer spring...correct me if I am wrong guys...I just though I remembered someone telling me that, once upon a time.

 

I seem to be having a little bit of jetting trouble with my 2000 DS650.
I am at about 1150 ft.

I have the following mods:
All OMR stock carb mods.
Muffler end cap.
K&N air filter.
Big Gun CDI.
Dino Jet kit with needle.
145 pilot jet
heavy duty snorkel
15 tooth front sprocket
22 inch rear tires

Right now I have the pilot screwed out three turns, DJ needle on third groove from top, and a 195 DJ main jet. In fifth gear I can only rev to 7000RPM and 71mph.
When My DS650 was bone stock I was clocked at 81mph and I don?t know the RPM because I didn?t have a tach yet. I am using a GPS to clock my speed so it should be accurate. I have tried DJ main jets from 175 up to 195 and the spark plug still seems pretty white and lean.
So any input would be great. I had hopes of hitting the rev limit in fifth gear with a top speed of over 85mph. In case your wondering I am about 220lbs, I don?t think it?s me.
Let me know.
Thanks.

 

Step 7 AIR - LID OFF (Race and / or No Water)

Lets review why the stock carb runs lean at high rpm's with lid off:

The factory built the DS to meet emission and speed regulations.
For many years all builders hated cv carbs because they needed negative pressure created by a closed air box to help slide and fuel control in the carb.

So how do we out smart all the above.
First, improve the exhaust system.
Second, rebalance the carb to match the motor needs - stock carb mods.
Third, control the negative pressure inside the carb, not in the airbox. - this is new.
Air going threw the venturi generates negative pressure, slide rises and fuel is drawn up the needle jet. Before fuel can rise quickly it needs to be atomized, thus the emulsion tube adds air to the fuel. Where does the air come from, threw the air jet on the right front of carb air intake. Side where throttle cable is mounted. Other side jet is for the pilot jet system.
But what happens when you allow outside air to enter the venturi area of a carb that has not been threw a tapered orifice?
It now becomes a air bleed. It now reduces the negative pressure in the venturi and has rpm's rise it starts to lose its ability to draw fuel up fast enough to match the air requirements. Fuel mixture starts to run lean.
The air bleeds control the mixture mostly at mid to high rpm. The air bleeds are best described as a controlled air leak in the main circuit. The air bleeds work by "bleeding off" this vacuum, which draws fuel through the main jets. A larger air bleed will make the mixture leaner at high rpm by bleeding off more vacuum or "signal."
How do we adjust for this condition? Install a smaller air bleed to richen the high rpm mixture by bleeding off less signal.

The fix:
The main air jet in the DS is a number 120.
The main air jet in a Quest or Traxter is a number 40
Part number 707200187
120 is actually a .037" hole.
40 is a .022" hole

The 40 still supplies all the air needs for the emulsion tube, but maintains the negative pressure to supply the needed fuel for high rpm's with the lid off.
For times that we are riding with the lid-on, jet accordingly, but there is added power at high rpm's also.

With the air snorkel removed from the front of carb, when looking straight into the carb venturi, the air jet is at the 3 o'clock position. Same side as the throttle cable. You will need a small screwdriver to remove the jet. Cost is around $8.00
When reinstalling, do not overtighten, small threads.
This will richen the mainjet by about 2 jet sizes and not allow the top end to lean out.



A DG170 or 175 should be main jet size.