Edlebrock slight cracked throttle burble


26 replies to this topic
  • Krannie McKranface

Posted March 26, 2008 - 06:16 PM

#1

'01 XR650R with Edle, full box mod, and fmf pipe. No decel pop.
At partial throttle, just above idle, I get a nasty "burble" that causes a mild but consistent flat spot with surging. It is very noticable at only one throttle position, at any rpm. Adjusting the AP did nothing.
Am I too rich?
It started after the new high flow header and two additional rich clicks.....

  • husky123

Posted March 27, 2008 - 03:00 AM

#2

Krannie,

You are probably a touch too rich with a burble and a flat spot. I good running 650R with the eddie will have some "slight" popping on decel...very normal. If you have tuned it to not have any you could be too rich. That is definitely the throttle opening affected by your MAT. Go left young man!

  • XR_RON

Posted March 27, 2008 - 06:02 AM

#3

Ive watched some Baja 1000 dvds,with the big guys in the drivers seat,and you know every thing that could be done to their bikes was done tuned,modded,upgraded etc,and I could hear some poping when they backed off the gas,Id say its normal,you know the race teams have their XR650r"s singing when they enter a race as hard as that.

  • Thumpage

Posted March 27, 2008 - 08:31 PM

#4

Krannie, what are you at, click wise, (***from full rich***) & what is your pump screw set at?

Make sure you come to the Fremont ride. There will be at least a couple/few 650R riders out there with Edel's on the bikes. It may help to compare settings and setups.

  • Krannie McKranface

Posted March 28, 2008 - 05:59 AM

#5

Krannie, what are you at, click wise, (***from full rich***) & what is your pump screw set at?

Make sure you come to the Fremont ride. There will be at least a couple/few 650R riders out there with Edel's on the bikes. It may help to compare settings and setups.


Thanks all for the great replys: I'm going 1 click leaner and see what happens. Regarding freemont: We will have to wait and see if my master (my business) will let me go.........

  • Krannie McKranface

Posted March 28, 2008 - 01:41 PM

#6

Krannie, what are you at, click wise, (***from full rich***) & what is your pump screw set at?

Make sure you come to the Fremont ride. There will be at least a couple/few 650R riders out there with Edel's on the bikes. It may help to compare settings and setups.


I don't know where my pump is set from stock. I think it is 1.5 out from full in.
I went two clicks leaner, and the problem went away, but I did loose 5 seat-of-the-pant HP. I think I need to go to the 21 needle, and a leaner click setting, yes?

  • Thumpage

Posted March 29, 2008 - 03:09 PM

#7

I don't know where my pump is set from stock. I think it is 1.5 out from full in.
I went two clicks leaner, and the problem went away, but I did loose 5 seat-of-the-pant HP. I think I need to go to the 21 needle, and a leaner click setting, yes?


1.5 turns out on the pump screw is the standard starting point. I currently have mine 2.5 turns out, meaning less pump shot. You only need enough to keep the bike from having a hiccup when whacking the throttle open fast. Any more than that and the bike will not be as crisp as it should be or may even feel a little lazy before it cleans out after building up in revs. Just a guess, but maybe you are a little rich on the pump setting and that is why the bike is not feeling or responding like it should?

I have never read of anyone actually using a 21E needle on a stock motor. But at the adjustment a few of us are currently at, it does make me wonder.
I think our fuel has a play in this as well. I have seemed to notice that going from summer/fall gas to winter gas has seemed to require changes in needle & pump settings as well. :prof: :bonk:

  • Krannie McKranface

Posted March 29, 2008 - 03:24 PM

#8

1.5 turns out on the pump screw is the standard starting point. I currently have mine 2.5 turns out, meaning less pump shot. You only need enough to keep the bike from having a hiccup when whacking the throttle open fast. Any more than that and the bike will not be as crisp as it should be or may even feel a little lazy before it cleans out after building up in revs. Just a guess, but maybe you are a little rich on the pump setting and that is why the bike is not feeling or responding like it should?

I have never read of anyone actually using a 21E needle on a stock motor. But at the adjustment a few of us are currently at, it does make me wonder.
I think our fuel has a play in this as well. I have seemed to notice that going from summer/fall gas to winter gas has seemed to require changes in needle & pump settings as well. :prof: :bonk:


It's all good.

  • jetfuel

Posted March 29, 2008 - 05:25 PM

#9

You only need enough to keep the bike from having a hiccup when whacking the throttle open fast. Any more than that and the bike will not be as crisp as it should be or may even feel a little lazy before it cleans out after building up in revs. Just a guess, but maybe you are a little rich on the pump setting and that is why the bike is not feeling or responding like it should?


That described perfectly what I needed to readjust on my "L" but just couldn't quite put my finger on it...Thanks, Thumpage:thumbsup:

Good gas for you...

  • prairiexr

Posted March 29, 2008 - 05:26 PM

#10

I just installed the 21 needle in my stock 650R. I am uncorked but otherwise stock. I'll let you know how it runs when the snow stops. (two feet this weekend so far)

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Krannie McKranface

Posted March 29, 2008 - 07:18 PM

#11

1.5 turns out on the pump screw is the standard starting point. I currently have mine 2.5 turns out, meaning less pump shot. You only need enough to keep the bike from having a hiccup when whacking the throttle open fast. Any more than that and the bike will not be as crisp as it should be or may even feel a little lazy before it cleans out after building up in revs. Just a guess, but maybe you are a little rich on the pump setting and that is why the bike is not feeling or responding like it should?

I have never read of anyone actually using a 21E needle on a stock motor. But at the adjustment a few of us are currently at, it does make me wonder.
I think our fuel has a play in this as well. I have seemed to notice that going from summer/fall gas to winter gas has seemed to require changes in needle & pump settings as well. :prof: :bonk:


Ok Thumpage, help me with this:

On my X adjusting the pump amount and duration are two separate circuits: diaphram linkage and leak jet. I have mine adjusted so it will have maximum throttle response off idle, if rolled on very quickly, but not 'slammed' on. This works best for me, as slamming with the X just results in wheelspin do to light motor internals.
On the XRR, if I slam the throttle, at low rpm's (being in low rpms for a while) I get a very quick and almost total hesitation, and if I do it at mid or higher rpm's, I get a slight surge, a very momentary lapse in the surge, then a normal surge up in rpm's.
I am not sure what this is telling me!

  • Krannie McKranface

Posted March 30, 2008 - 12:50 PM

#12

..........bump

  • Thumpage

Posted March 30, 2008 - 02:06 PM

#13

Ok Thumpage, help me with this:

On my X adjusting the pump amount and duration are two separate circuits: diaphram linkage and leak jet. I have mine adjusted so it will have maximum throttle response off idle, if rolled on very quickly, but not 'slammed' on. This works best for me, as slamming with the X just results in wheelspin do to light motor internals.
On the XRR, if I slam the throttle, at low rpm's (being in low rpms for a while) I get a very quick and almost total hesitation, and if I do it at mid or higher rpm's, I get a slight surge, a very momentary lapse in the surge, then a normal surge up in rpm's.
I am not sure what this is telling me!


Sorry for the delay.

Well, as we know, the pump shot of the Edelbrock is only adjustable for volume. In any event, dialing in the needle setting is done with rolling on the throttle. Then after the needle is tuned, then start dialing in the pump shot with quick twists of the throttle.
Note of reference: (If someone is trying to dial in the needle with quick throttle twists, the pump shot can overshadow proper needle adjusment).

I have a feeling that you could possibly have a slight air leak at the manifold. You could try rotating both clamps,(carb side & cylinder side of the manifold) let's say a quarter rotation and retightening them. This may help close up any air leakage from an old compressed manifold where the clamps have made their usual indentations and new gaps. Then try redialing in the carb.
The reason I say this is because the surging could be a lean condition but you may be trying to compensate with both richer needle and pump shot settings. Hence, the back and forth between surging and burbles. A lean condition from an air leak could be making you turn down the idle screw enough that the bike is also not in the normal idle speed range to be responsive without that stumble. It all comes back to you possibly trying to use richer settings than is needed to get the bike to have the throttle response that is expected with an Edelbrock.
I could be off base, but that is what is coming to me at the moment.

  • Thumpage

Posted March 30, 2008 - 02:12 PM

#14

That described perfectly what I needed to readjust on my "L" but just couldn't quite put my finger on it...Thanks, Thumpage:thumbsup:

Good gas for you...


Jetfuel,

I am glad what I had to offer could help you out. Thank you for the gas, it is well appreciated. :prof:

  • Thumpage

Posted March 30, 2008 - 02:24 PM

#15

I just installed the 21 needle in my stock 650R. I am uncorked but otherwise stock. I'll let you know how it runs when the snow stops. (two feet this weekend so far)


I can see if it is really cold, lower elevations and you have open spaces to ride more wide open, that needle might work well. We could use more details of what muffler or extent of your muffle tip modification, holes in the sidecover?, why you decided on the 21E needle, ie.,(what settings were you running with the 19E?) etc..

Give us more of the backround of your decision to start with. :prof:

  • Krannie McKranface

Posted March 30, 2008 - 07:11 PM

#16

Sorry for the delay.

Well, as we know, the pump shot of the Edelbrock is only adjustable for volume. In any event, dialing in the needle setting is done with rolling on the throttle. Then after the needle is tuned, then start dialing in the pump shot with quick twists of the throttle.
Note of reference: (If someone is trying to dial in the needle with quick throttle twists, the pump shot can overshadow proper needle adjusment).

I have a feeling that you could possibly have a slight air leak at the manifold. You could try rotating both clamps,(carb side & cylinder side of the manifold) let's say a quarter rotation and retightening them. This may help close up any air leakage from an old compressed manifold where the clamps have made their usual indentations and new gaps. Then try redialing in the carb.
The reason I say this is because the surging could be a lean condition but you may be trying to compensate with both richer needle and pump shot settings. Hence, the back and forth between surging and burbles. A lean condition from an air leak could be making you turn down the idle screw enough that the bike is also not in the normal idle speed range to be responsive without that stumble. It all comes back to you possibly trying to use richer settings than is needed to get the bike to have the throttle response that is expected with an Edelbrock.
I could be off base, but that is what is coming to me at the moment.


This all makes sense. I actually found the front a rear boots very loose one day after 'finally dialing in' the needle, only to start over again with the now tight boots. I usually check for air leaks on the intake with a can of compressed cleaner (like contact cleaner) sprayed around the possible leak areas, causing an immediate rise in rpms. I'll try it and see what happens.
I like the way the bike runs, but now without the burble, there is a noticable drop in mid/top power.

Thanks for all your help.

  • prairiexr

Posted March 31, 2008 - 02:39 PM

#17

I can see if it is really cold, lower elevations and you have open spaces to ride more wide open, that needle might work well. We could use more details of what muffler or extent of your muffle tip modification, holes in the sidecover?, why you decided on the 21E needle, ie.,(what settings were you running with the 19E?) etc..

Give us more of the backround of your decision to start with. :prof:


I have the HRC tip, otherwise a stock exhaust. Right now the average temperature is about 25, and i am at 1000 feet of elevation. I do ride a lot of open spaces, but also play in the valleys.
I was running the 19E and had good pull from top to bottom, but when i backed off i felt i had far too much popping and banging, as if it were to lean from long wide open pulls. Also I had adjusted the mid range as rich as it could go with no affect on the popping and banging.
My current hypothesis is that with the 21E needle I should be able to eliminate the popping and banging, then then slowly lean it out with the needle adjustment until i get slight popping and banging back on deceleration.

If this needle proves too rich I may "tune" it by modifying my airbox, and/or my exhaust further.

Also when running the stock carb, I found all the posted needle and jet settings to be far too lean. Never did get that carb to perform well, though I never tried to go much richer with it. Perhaps I have an extra healthy engine that likes it's air and fuel, or perhaps my fuel is different than what you guys run down there.

  • prairiexr

Posted March 31, 2008 - 02:40 PM

#18

why isn't there a 20e needle?

  • Agent2

Posted March 31, 2008 - 03:43 PM

#19

why isn't there a 20e needle?

There is - http://www.denniskir...=p172259&mmyId=

  • Thumpage

Posted April 01, 2008 - 09:00 AM

#20

This all makes sense. I actually found the front a rear boots very loose one day after 'finally dialing in' the needle, only to start over again with the now tight boots. I usually check for air leaks on the intake with a can of compressed cleaner (like contact cleaner) sprayed around the possible leak areas, causing an immediate rise in rpms. I'll try it and see what happens.
I like the way the bike runs, but now without the burble, there is a noticable drop in mid/top power.

Thanks for all your help.


Hope it helps towards getting it dialed at least a little better. Do your best to try and make it out to the ride. :prof:





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