Edelbrock carb adjustment for better breathing XR650?


6 replies to this topic
  • Suikerland

Posted May 11, 2009 - 01:44 AM

#1

I recently installed an Edelbrock on my 650R. Unfortunately it's a bit of a "black box" to me, meaning I got it pre-jetted from Barnums, put it on, and away I went.
I don't even know what settings I have. (650R, sea level, stock headers, Staintune muffler with restrictor removed).

Now the question - I'm about to fit a slightly wider diameter (Staintune) header, so in theory the bike should breathe better. Do I need to richen the mixture on the Edelbrock? Any tips?

Also, does anyone know where I can get a PDF manual for the carb?
I got the instruction supplement for installing, but can't find manual or parts diagram.

Thanks all

  • BWB63

Posted May 11, 2009 - 05:03 AM

#2

That setup should be around 16 clicks from full rich with a #19 needle. What fuel you are running will make a difference but, it seems the pump screw is what has to move all the time. Rich tracy and I have found that the change of fuel here from season to season can change the need of the pump screw quite a bit to get the bike to run right. I have not found that I need to change the needle screw on the 650 but, change it on the XR400R twice a year.

  • creeky

Posted May 11, 2009 - 09:40 AM

#3

Here's a pdf file that should help. BWB's settings should be about right, play with the clicker a couple of clicks at a time to get the optimum setting.

http://www.edelbrock...b_internals.pdf

  • Suikerland

Posted May 11, 2009 - 06:45 PM

#4

Thanks guys.

To demonstrate my total ignorance of this carb (and no manual) I need to ask the following:

1) I assume the pump screw is the one near the bottom of the carb (on the right side of the bike) and the needle screw is the bigger dial on the top of the carb? (That's based on the diagram in the link above.)

2) Also, can you tell me turning which direction on each screw makes makes the mixture richer or leaner?

3) what part of the throttle range does each screw affect?

4) last - currently I'm using the third adjuster (that flops around on the end of the cable) simply to adjust idle as the bikes warms up? Is this correct?

Or, alternatively, can anyone point me to a basic "how-to" on this carb? I have no operating manual, and none of the mechanics I know are familiar with it. It's quite confusing after the using the stock carb.

Thanks

  • BWB63

Posted May 11, 2009 - 07:34 PM

#5

On both screws "R" Right (Clockwise) is Rich and "L" Left (Counter Clockwise) is Lean. The pump screw is a pump bypass screw out is more bypass (less fuel pumped more fuel bypassed) Full in is full pump, that would be full squirt of the fuel.

After pulling the throttle full and making the knob on top set into the grove counter clockwise (Left) screws the the needle down (Less fuel - leaner) and clockwise (Right) screws the needle up (more fuel - richer) But, you have to pull the throttle all the way up so, the slide will be all the way up and the needle carage will lock with the top knob. You do not want any poping on decel. That would be lean and you would nead to richen up the needle. No bog on quick twist of the throttle under load, this is lean on the pump. You want to do the quick twist in gear and make it just rich enough to stop the bog. It should bog a little with no load. To much pump and you should be able to kill the bike with the throttle (Way to much pump). Less pump is best, just enough to have the bike respond the best with the least amount of pump.
On the Idle I have to use about two screws in on the idle cable on a cold bike. Once warm I go back out the almost two turns.



Thanks guys.

To demonstrate my total ignorance of this carb (and no manual) I need to ask the following:

1) I assume the pump screw is the one near the bottom of the carb (on the right side of the bike) and the needle screw is the bigger dial on the top of the carb? (That's based on the diagram in the link above.)

2) Also, can you tell me turning which direction on each screw makes makes the mixture richer or leaner?

3) what part of the throttle range does each screw affect?

4) last - currently I'm using the third adjuster (that flops around on the end of the cable) simply to adjust idle as the bikes warms up? Is this correct?

Or, alternatively, can anyone point me to a basic "how-to" on this carb? I have no operating manual, and none of the mechanics I know are familiar with it. It's quite confusing after the using the stock carb.

Thanks



  • Suikerland

Posted May 11, 2009 - 09:33 PM

#6

that's what i need... how can I pay you ? :excuseme:

On both screws "R" Right (Clockwise) is Rich and "L" Left (Counter Clockwise) is Lean. The pump screw is a pump bypass screw out is more bypass (less fuel pumped more fuel bypassed) Full in is full pump, that would be full squirt of the fuel.

After pulling the throttle full and making the knob on top set into the grove counter clockwise (Left) screws the the needle down (Less fuel - leaner) and clockwise (Right) screws the needle up (more fuel - richer) But, you have to pull the throttle all the way up so, the slide will be all the way up and the needle carage will lock with the top knob. You do not want any poping on decel. That would be lean and you would nead to richen up the needle. No bog on quick twist of the throttle under load, this is lean on the pump. You want to do the quick twist in gear and make it just rich enough to stop the bog. It should bog a little with no load. To much pump and you should be able to kill the bike with the throttle (Way to much pump). Less pump is best, just enough to have the bike respond the best with the least amount of pump.
On the Idle I have to use about two screws in on the idle cable on a cold bike. Once warm I go back out the almost two turns.



  • chubbs0_3

Posted May 23, 2009 - 05:58 PM

#7

On both screws "R" Right (Clockwise) is Rich and "L" Left (Counter Clockwise) is Lean. The pump screw is a pump bypass screw out is more bypass (less fuel pumped more fuel bypassed) Full in is full pump, that would be full squirt of the fuel.

After pulling the throttle full and making the knob on top set into the grove counter clockwise (Left) screws the the needle down (Less fuel - leaner) and clockwise (Right) screws the needle up (more fuel - richer) But, you have to pull the throttle all the way up so, the slide will be all the way up and the needle carage will lock with the top knob. You do not want any poping on decel. That would be lean and you would nead to richen up the needle. No bog on quick twist of the throttle under load, this is lean on the pump. You want to do the quick twist in gear and make it just rich enough to stop the bog. It should bog a little with no load. To much pump and you should be able to kill the bike with the throttle (Way to much pump). Less pump is best, just enough to have the bike respond the best with the least amount of pump.
On the Idle I have to use about two screws in on the idle cable on a cold bike. Once warm I go back out the almost two turns.


wow!! good info on the pump!!! good stuff mate!





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