Bike won't idle down

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Hummbusa
Posts: 20
Joined: Sat Jul 14, 2007 5:34 pm

Bike won't idle down

#1

Post by Hummbusa » Mon Sep 29, 2008 4:46 pm

I am trying to get my panhead to slow the idle down. I have followed the steps as far as 5turns 2 turn adjust idle ect......
When I try to adjust the idle screw it don't really seem to matter I can go in 2 turns or out three and it just keeps picking
up speed or completely stalls..I also will take and force the idle screw lever back thinking it was maybe not returning all
the way and sometimes it slows the idle down but other times it don't. I also tried to attach a spring to the idle screw mount to make sure
its closing but it HIGH idles!!! Besides that it seems to run really good down the road.



51Hog
Posts: 655
Joined: Fri May 20, 2005 7:29 pm
Location: Wasilla, Alaska

Re: Bike won't idle down

#2

Post by 51Hog » Mon Sep 29, 2008 7:14 pm

Sounds like a vacuum leak.
Is the throttle disk worn? Is there an eyebrow cut into the side of the carb barrel where the throttle disk closes?
Is the float level correct in the carb? How bout the throttle shaft and bushings?
Manifold leak?
Dale

awander
Posts: 1127
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH

Re: Bike won't idle down

#3

Post by awander » Mon Sep 29, 2008 7:26 pm

Are you using the stock inside-the-handlebar control coils & spirals? If so, I think maybe when you roll off the throttle, it is not retracting the control cable enough, and this won;t allow the carb disk to close all the way.

Hummbusa
Posts: 20
Joined: Sat Jul 14, 2007 5:34 pm

Re: Bike won't idle down

#4

Post by Hummbusa » Mon Sep 29, 2008 8:27 pm

Thanks for the quick response!!
I will look at the throttle disk...whatever that is :)(i'm not around the bike or manual).
Yes it does have the internal wire but would it not release when I push it back with the
screwdriver and if not how do I give it slack.

awander
Posts: 1127
Joined: Fri Sep 21, 2007 3:03 am
Bikes: '52 FL
'64 FLH

Re: Bike won't idle down

#5

Post by awander » Mon Sep 29, 2008 9:01 pm

The stock internal wire works backwards from the newer ones that most bikes have nowadays. It pushes the wire out to opemn the throttle, and then pulls it back when you close the throttle. If it is out of adjustment or stretched, it may not be able to pull the wire back far enough to close the throttle, and since it is a pretty rigid solid wire, you may not be able to manually close the throttle at the carb with the control wire attached.

Try disconnecting the control wire at the carburetor, and move the linkage by hand to vary the engine speed.

FlatHeadSix
Moderator
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Bikes: '31 VL, '34 VD, '45 WLA, '47 WL, '49 FL, '51 WL, '58 ST (Hummer), '71 GE (Servi)
Location: Lonoke, Arkansas

Re: Bike won't idle down

#6

Post by FlatHeadSix » Mon Sep 29, 2008 9:19 pm

Hummbusa,
The "Idle" adjustement on the Linkert only raises and lowers the low speed needle in its seat to change the air/fuel mixture for the idle circuit, it is NOT for actually adjusting the idle speed. (although it will affect it somewhat). Once you have the high and low speed needles dialed in you adjust the final idle speed using the stop screw on the throttle lever itself.

Before you start tearing the handlebars apart and messing around with your spirals, try backing the screw on the throttle lever out a little.

mike

FlatHeadSix
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Location: Lonoke, Arkansas

Re: Bike won't idle down

#7

Post by FlatHeadSix » Mon Sep 29, 2008 9:26 pm

a picture might help, look at reference #5, Throttle Stop Screw

Image

Hummbusa
Posts: 20
Joined: Sat Jul 14, 2007 5:34 pm

Re: Bike won't idle down

#8

Post by Hummbusa » Tue Sep 30, 2008 4:25 am

FlatHeadSix wrote:a picture might help, look at reference #5, Throttle Stop Screw
Thats the screw I'm talking about #5. It don't really matter if its in or out. It flat out stalls or idles high
I would guess 2000+ rpms. When I stop at a light or corner it sounds like a sewing machine on tilt.

I am not sure how to adjust the spirals...if I disconnect the wire I don't think I could get it up to running temp
without burning my fingers off :)

FlatHeadSix
Moderator
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Location: Lonoke, Arkansas

Re: Bike won't idle down

#9

Post by FlatHeadSix » Tue Sep 30, 2008 12:56 pm

Humm Dude,
Loosen the screw which clamps the control wire to the swivel in the throttle lever on the carb so that the wire will slip. Twist your grip as far as it will go in the closed position. Hold the throttle lever on the carb tightly against the stop, all the way closed. While holding the carb closed, turn the grip slightly to the open position and then tighten the clamp screw securely.

Now go through the adjustment procedure in the shop manual again, in the order it states. The five turns out on the low speed needle is a little excessive (and very rich) you may want to try something less, two turns out on the high speed needle should be about right. The last thing you adjust is the throttle stop screw to get your desired idle speed.

If all that doesn't work then you have some internal problems in the Linkert and it will have to come off. If it will not idle properly you may have something blocking a passage in the idle circuit or the throttle disc may have worn a groove in the carb body at the point where the little tiny idle oriface holes are located.

good luck

mike

Cotten
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Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Bike won't idle down

#10

Post by Cotten » Tue Sep 30, 2008 2:52 pm

My money's on the vacuum leak.

....Cotten

King
Posts: 373
Joined: Fri Apr 02, 2004 5:05 pm

Re: Bike won't idle down

#11

Post by King » Tue Sep 30, 2008 3:08 pm

Mine too. Does it idle/run better with the choke partially closed? That's a nearly foolproof sign of air leaking in somewhere.

King

steve_wood
Posts: 947
Joined: Tue Jan 08, 2008 12:32 am
Bikes: 56 FLH, 2007 FLHRCI
Location: Belleville, Ontario, Canada

Re: Bike won't idle down

#12

Post by steve_wood » Mon Oct 13, 2008 7:56 pm

Hummbusa:

Did you ever isolate the problem?

steve

Hummbusa
Posts: 20
Joined: Sat Jul 14, 2007 5:34 pm

Re: Bike won't idle down

#13

Post by Hummbusa » Mon Oct 13, 2008 8:08 pm

I adjusted the wire leading to the carb to make sure it was completely returning when rolling off the throttle.
I started it up and ran it for 3-5 minutes and all seemed well then my battery took a dive. Which upon further investigations burned
the outside positive wire cover all the way to the junction box. I have made a new wire and am waiting for a new sealed 6 volt to arrive(seeing what they are like)
I still wonder though if I have a vacuum leak because the bike would idle fine on occasion then lose its mind on others. My old biker buddy and I was talking about checking for the vacuum leak. I told him about Cottens method and he suggested spraying some starting fluid around the manifold and see if the bike idles up then we will do the other way...good to have friends that really ride old bikes!! Shoot it will be snowing here before long and I can't wait to get the old girl back out on the road.

Cotten
Posts: 6791
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois

Re: Bike won't idle down

#14

Post by Cotten » Tue Oct 14, 2008 12:32 pm

Hummbusa!

The problems with the barnyard method of squirting flammables around the manifold are that (1) it misses anything but a large leak, (2) it doesn't display exactly where or how much it might leak, and (3) the motor must be running.

Consider also if that hot wire problem had ignited starting fluid under your gastank!
(Even a steam radiator can ignite ether.)

Soap-bubbletesting is absolute, exact, and safe.
You can cut to the chase before the battery even arrives!

....Cotten

VintageTwin
Panhead Register Member
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Bikes: '46 Knuck. '57 Panhead, '59 Panhead
Location: Repop Hell

Re: Bike won't idle down

#15

Post by VintageTwin » Tue Oct 14, 2008 2:57 pm

Check out MIke's manifold leak tester. Got one. Nice tool.

----------------------------------------------------
You can use a long screwdriver to push the throttle lever completely shut while the motors running. With the end of the screwdriver you can feel the throttle lever move slightly and bottom on the stop. If this happens, take off the right tank half. Sometimes you have to angle the control coil downward a little at the top frame clamp. You don't want too much control coil (about 1-1/2" to 2") extending beyond the (top) frame clamp.
But, the rising and lowering of idle speed sounds like a manifold leak.
cables1023ee0.jpg
This is the top frame clamp. You're able to tilt the coil downward a little. The control wire makes a radical drop to the (throttle lever) wire block.
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