52 panhead idle goes up after warm up.

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james
Posts: 832
Joined: Tue Nov 18, 2008 7:33 pm
Bikes: 2003 FLHRCI
1952 FL
Location: Wrightsville Pennsylvania

52 panhead idle goes up after warm up.

#1

Post by james » Sun Aug 23, 2009 8:54 pm

Hello to all,
52 panhead all stock. Starts on 2 kicks cold. Runs fine. After running a mile or two, come to a stop the idle is higher than what it was when I started out. About 500 rpm higher. I know a vacuum leak can cause a higher idle, it has peek seals on the intake and everything is sealed tighter than a drum. Also the throttle stop adjuster hits the carb body like it should when throttle is closed. When I brought it back to the garage today after a 10 mile run the rpm was @ 1,200 so I adjusted it down at the throttle stop about 1/2 turn out. Sat there idling fine. Checked the fine tune of the mixture screw all good.
One last note the carb still leaks after sitting a while, it drips out the gasket between the manifold and the spacer. Have had the carb off so many times it needs a zipper. I usually run the fuel out of the carb when I park it after shutting off the tank valve but the tank shut off valve works about 98% and gas still ends up getting to the carb.

Why do we say something is out of Wack? What's a Whack? :(
jim



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

Re: 52 panhead idle goes up after warm up.

#2

Post by Cotten » Mon Aug 24, 2009 2:37 am

Jim!

Since a rising idle is such a signature of a vacuum leak, I really must ask:
When you pressuretested the manifold assembly, did you also squirt soapy water upon the pan cover screws over each intake port?

It is not the most common problem for the screw holes to be perforated into the port, but it is a diabolical one if you miss it....

The next suspect is the throttle control linkage itself.
The coil and the wire are both springs.
If they naturally relax to a position that wants to open the throttle lever, you will get that same aggravating symptom when your hand is off the grip. Please inspect to see that there is no reversing tension when the front fork is cocked one way or the other.
Any slack in the control wire between the throttlelever and the secured control coil is suspect of springing to where it shouldn't be.

And a 100% petcock is not easy to achieve, but the carb floatvalve was never designed to hold back gas absolutely, only to regulate it. Face it, it operates open.

Good luck!

...Cotten

james
Posts: 832
Joined: Tue Nov 18, 2008 7:33 pm
Bikes: 2003 FLHRCI
1952 FL
Location: Wrightsville Pennsylvania

Re: 52 panhead idle goes up after warm up.

#3

Post by james » Tue Sep 08, 2009 1:18 pm

Cotten wrote:Jim!

Since a rising idle is such a signature of a vacuum leak, I really must ask:
When you pressuretested the manifold assembly, did you also squirt soapy water upon the pan cover screws over each intake port?

It is not the most common problem for the screw holes to be perforated into the port, but it is a diabolical one if you miss it....

The next suspect is the throttle control linkage itself.
The coil and the wire are both springs.
If they naturally relax to a position that wants to open the throttle lever, you will get that same aggravating symptom when your hand is off the grip. Please inspect to see that there is no reversing tension when the front fork is cocked one way or the other.
Any slack in the control wire between the throttlelever and the secured control coil is suspect of springing to where it shouldn't be.

And a 100% petcock is not easy to achieve, but the carb floatvalve was never designed to hold back gas absolutely, only to regulate it. Face it, it operates open.

Good luck!

...Cotten

Forget about this post, I found the problem. Loose throttle cable screw at carb. The kink in the cable kept it from pulling out all the way.

Thought I'd let you know.
Jim

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