Panhead just won't start

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alarki2
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Panhead just won't start

#1

Post by alarki2 »

I have a 1960 duo glide that was taken to bits by my dad about 5-6 years back now. Started as replace exhaust turned into tearing all of the top end off. Anyway, he put her all back together and left it not running. After that it sat for about 5 years. I have since started to work on it tryIng to get it going.
I've got it to the point now where I can get it to start but it will only run at a high rpm and will only run for about 45secs before it dies out. When you try and bring it down to an idle it immediately cuts off. I'm thinking it must be a fuel issue but this is the first bike I've ever really worked on and don't want to just go chasing everything to where I am back at a full tear down.
It has spark and compression. And it must be getting some fuel if it runs at all right? It's all stock on a 6v system. Wanted to know if anyone here had any suggestions? I think the fuel lines and or the carb jets could be gunked up starving it of fuel. But don't know exactly the best way to get in there and clean them.

Thanks for help
George Greer
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Re: Panhead just won't start

#2

Post by George Greer »

Start by downloading this manual.

app.php/knowledgebase/category?id=17

Then do a search on manifold leak checks, you probably have a manifold leak.

What type of carb is on it?

Look at Cottens posts, and you will get a better idea of what to do.

Others here will chime in soon.

Good Luck

George Greer
Cotten
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Re: Panhead just won't start

#3

Post by Cotten »

Alarki2!

As George points out,
The most common cause for such grief is a vacuum leak at the manifold.
To find the sweet spot where the assembly seals properly, and to prevent overtightening of the clamps, you can use soap bubbles:
http://virtualindian.org/11techleaktest.html

Please also test the pan cover screws over each intake port (the ones closest the top motormount studs), as occasionally they have been perforated.

Let us know how it goes,

...Cotten
alarki2
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Re: Panhead just won't start

#4

Post by alarki2 »

George. The carb on it is a model m carb.

Thanks for the link to the manual, but I actually have it in the book form!

Didn't have time to fiddle with it tonight. Hopefully tomorrow.
Will update then.
alarki2
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Re: Panhead just won't start

#5

Post by alarki2 »

welp, worked on bike some today. tightened all the pan bolts i could reach without taking off the tanks. And tightened the clamps for the manifold. Both were a little loose, not all pan bolts but one had space under it! Dad swears he had them all snugged down nicely. anyway, primed the bike with a few kicks then turned switch on and she fired up on about the 3-4 kick. since i reset the carb to what the manual said, i had timing all the way advance for start. then i took choke off completly and retarded timing some and bike was idiling away. She sat and ran for about 3-4mins. I just left it sit there and idle while i stepped out of garage to hear (damn thing is loud, brings the neighbors out every time!) While away, bike all of a sudden revved up real high and died out.
I did try the soapy bubble test. haven't made up a contraption to put engine under pressure, but instead had my dad spray soapy solution around while i slowly turned engine over. Didn't see bubbles popping out anywhere, but there must have been some form of leak if tightening things down is what has helped thus far.
It ran longer this time so i'm wondering now if it is a tuning issue at this point or do you all think there is still a air leak somewhere. instead of making a plate for the carb to do the airpressure test a cork could also be used correct? or can you order one of those test plates for cheap? it'd be worth it if its going to make testing super simple, since the turning engine over method didn't seem to produce that good of results.
Bigincher
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Re: Panhead just won't start

#6

Post by Bigincher »

Personally, I think it could be something simple.
You can fashion your own block-off plate for the manifold to do a proper bubble test, which is good to do, but in this case doesn't really sound like the culprit.
I would more likely suspect the fuel delivery, such as float or needle valve.
So if you remove the carb to do the prudent bubble test (it's worth doing anyway), you'll have the carb in your hands and can drop the float bowl and check that the float isn't swolen and that the needle valve functions properly.

You're almost there, don't go getting carried away with a bunch of unneccesary stuff at this point.... it will only confound the issue..!
George Greer
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Re: Panhead just won't start

#7

Post by George Greer »

If you pull off your carb make a tester plate for your manifold.

And once you remove the carb bowl, look and see if you might be hanging up on the stem.

See also if you have a brass float..........if you do, throw it in the trash, and get one of Cottens floats.

That one part alone cured many issues on my WLA's M-88 carb, along with the advice from many about the EVIL manifold leak...... I too now firmly believe in how EVIL leaks are.

My lawm mower does the same thing.........Runs really high RPM......then dies, Just before running out of gas.

Hope my little 2 euro cent worth helps.

George
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Re: Panhead just won't start

#8

Post by Cotten »

Alarki2!

The manifold variable should be addressed, even if other problems are found.

It requires a constant, regulated supply of twelve to fifteen psi for a bubbletest to be meaningful.

While disassembled, it is important to grind the mating carburetor and manifold flanges, and the phenolic block. as flat as possible. They are invariable warped.

.....Cotten
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