Idle Mix Screw

Unsprung

In the Potters hand...
I Was having some issues with getting my carb dialed in, (running lean at times with slight popping at road speeds and coughing in the carb). 31/76 jets with V&H BR, baffles installed. I believe my idle mix screw was turned in too much by the PO and the hole has now been opened to where stock setting is not right. The pic below shows the screw hand tightened until it’s just touching. The screw also has wear at the tip where it sits in the hole. Please take a look at the pic and let me know if I’m over thinking this. Thanks in advance for any help, comments, and wisecracks.
B57FA370-16C1-4BCD-A75D-DF2B0C585351.jpeg
 

Unsprung

In the Potters hand...
Dude! Just so happens I have a Super G on my bench. Screwed the scree all the way in, and it does not come through at all. Pulled it out and the hole for the needle seat is about the size of a straight pin.
That says it all Shannon, need a new carb. I can run it but it’s time to go shopping. That sucks
 

john sachs

Well-Known Member
I Was having some issues with getting my carb dialed in, (running lean at times with slight popping at road speeds and coughing in the carb). 31/76 jets with V&H BR, baffles installed. I believe my idle mix screw was turned in too much by the PO and the hole has now been opened to where stock setting is not right. The pic below shows the screw hand tightened until it’s just touching. The screw also has wear at the tip where it sits in the hole. Please take a look at the pic and let me know if I’m over thinking this. Thanks in advance for any help, comments, and wisecracks.
View attachment 53651
Fragile area. Someone screwed it in to far, and screwed it up.Carb needs to be replaced.
John
 

Unsprung

In the Potters hand...
Fragile area. Someone screwed it in to far, and screwed it up.Carb needs to be replaced.
John
Thanks John, got the bike in August and never could get it set right. Local tech told me to check the seating of the screw. Bingo - it’s shot. Oh well, it is what it is.
 

Unsprung

In the Potters hand...
New carb was delivered yesterday from BigDogPartsKing and waiting on new orings and gaskets to get here. New DEKA battery is installed, last one was 8 years old, (11/10), so I got the exact battery. Hopefully have it up and running by Wednesday and it doesn’t rain next week on the Monday ride up. Should run much better with fuel ratio set correctly. Bags already packed.
 

Unsprung

In the Potters hand...
Carb was installed yesterday and still not right. Gave Ker a call and after chatting with him got back into it, (thanks Ker). Drained fuel, checked shut off valve filter and reinstalled. New gas a little sea foam and it’s running better. Adjusted carb a little bit and let it idle. It still pops through the exhaust and the idle does not sit at 1k, (blinks from 1st light to 2nd). Starts right up and runs but can’t seem to get idle just right. I need to ride it and see what’s going on but I’ll do that tomorrow. I’ll readjust from stock once more and see what happens.
 

Butch Cassidy

Active Member
Carb was installed yesterday and still not right. Gave Ker a call and after chatting with him got back into it, (thanks Ker). Drained fuel, checked shut off valve filter and reinstalled. New gas a little sea foam and it’s running better. Adjusted carb a little bit and let it idle. It still pops through the exhaust and the idle does not sit at 1k, (blinks from 1st light to 2nd). Starts right up and runs but can’t seem to get idle just right. I need to ride it and see what’s going on but I’ll do that tomorrow. I’ll readjust from stock once more and see what happens.
... with all the different 'settings' that have been used... take a quick look at the plugs... might put in a new set to start fresh.
 
Fragile area. Someone screwed it in to far, and screwed it up.Carb needs to be replaced.
John
I wonder if you could run a tap to clean up the threads and loctite and insert a helicoil into the carb? As long as the body is not cracked?
I would be concerned with the motor sucking up the helicoil.. I know he ordered a new carb but more of a what if.


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Carb was installed yesterday and still not right. Gave Ker a call and after chatting with him got back into it, (thanks Ker). Drained fuel, checked shut off valve filter and reinstalled. New gas a little sea foam and it’s running better. Adjusted carb a little bit and let it idle. It still pops through the exhaust and the idle does not sit at 1k, (blinks from 1st light to 2nd). Starts right up and runs but can’t seem to get idle just right. I need to ride it and see what’s going on but I’ll do that tomorrow. I’ll readjust from stock once more and see what happens.
Could be an exhaust leak or it could be a manifold leak, may be worth pulling off the manifold and getting new gaskets, also check the rubber cap on the manifold, they can dry rot and crack and cause problems with the idle. Last thing I can think of is the insert the connects your carb to manifold also has an o ring in it that may need replaced.



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Unsprung

In the Potters hand...
Could be an exhaust leak or it could be a manifold leak, may be worth pulling off the manifold and getting new gaskets, also check the rubber cap on the manifold, they can dry rot and crack and cause problems with the idle. Last thing I can think of is the insert the connects your carb to manifold also has an o ring in it that may need replaced.



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Pipes are tight but I my pull and check for damaged gaskets since I replaced them last month. Manifold had no leaks when I checked back in dec or Jan but I’ll get brake clean and spray a bit. Rubber cap is new, only one on back of carb. New o rings and gaskets all around with carb install. Ker mentioned possible exhaust leaks but I don’t see any trace of leaking around the engine.
 

Th3InfamousI

Administrator
Staff member
Pipes are tight but I my pull and check for damaged gaskets since I replaced them last month. Manifold had no leaks when I checked back in dec or Jan but I’ll get brake clean and spray a bit. Rubber cap is new, only one on back of carb. New o rings and gaskets all around with carb install. Ker mentioned possible exhaust leaks but I don’t see any trace of leaking around the engine.
I'm confused on the idle issue not hitting 1k. If you keep turning the idle screw clockwise you still can't increase the idle and get the tach from blinking?

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Unsprung

In the Potters hand...
I'm confused on the idle issue not hitting 1k. If you keep turning the idle screw clockwise you still can't increase the idle and get the tach from blinking?

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Not sure how to explain it but it seems like it’s missing, the 1k light is steady for a minute and once it’s hot seems the light blinks from 500 to 1000 even after I turn the idle speed screw. Ker, like Paul said sounds like an exhaust leak I installed new tapered exhaust donuts last month so I will pull them out and check for leaks. Intake was solid last I checked with brake cleaner. I thought it was good to go, even called Ker and told him it was running better but....
 
Pipes are tight but I my pull and check for damaged gaskets since I replaced them last month. Manifold had no leaks when I checked back in dec or Jan but I’ll get brake clean and spray a bit. Rubber cap is new, only one on back of carb. New o rings and gaskets all around with carb install. Ker mentioned possible exhaust leaks but I don’t see any trace of leaking around the engine.
Understand


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Th3InfamousI

Administrator
Staff member
Not sure how to explain it but it seems like it’s missing, the 1k light is steady for a minute and once it’s hot seems the light blinks from 500 to 1000 even after I turn the idle speed screw. Ker, like Paul said sounds like an exhaust leak I installed new tapered exhaust donuts last month so I will pull them out and check for leaks. Intake was solid last I checked with brake cleaner. I thought it was good to go, even called Ker and told him it was running better but....
So once it's at 1k then warms up and drops RPM to blinking range it still won't raise the idle if you turn the idle screw a bit?

Those tapered ones I've never had much luck with I prefer the old skool flat style (non-tapered) and just double them up.

These are the ones I get and anytime the exhaust comes off I just replace them so I keep the pack of 10 on the shelf. Haha


https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/191181084529
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