1972 Stock Dual Carbs -missing bits

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Oregon72
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1972 Stock Dual Carbs -missing bits

Post by Oregon72 » Fri Nov 21, 2008 10:39 pm

I'm working on getting the nerve up to attempt to tune my stock dual carbs. While reading colin's write-up, I decided I better take a trip to the garage to make sure I have all the appropriate bits and pieces as some things didn't seem right ---- DAMMIT!!! Why does my bus even run??

PO cut wire from the pilot cutoff to the central idle cutoff and yanked the spade out as well. What the hell??
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I have no hoses from right air cleaner horn to pre-heater or rubber T on right carb.
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Rubber T on right carb is capped with a little plastic cap on it. Why?

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What is the reasoning behind doing such things ? Is the central idle cutoff ruined or can it be saved. Does something just plug right into it or is it shot?

Thanks guys -
-'72 Westy-

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keifernet
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Post by keifernet » Sat Nov 22, 2008 8:08 pm

What you have found is not uncommon...

The big round "air bypass" solenoid is the same part as on the 34 pict 3 and H 30/31 single type 1 carbs and can be had new for around 25 bucks or less.

The other missing vac hoses can be traced down using the drawings by Colin and pictures on Richard Atwell's site.

Here is some help finding the info... there is more and Colin of course will probably respond with some input on here.


http://www.thesamba.com/vw/forum/viewto ... ight=hoses

Section 2:14 on here

http://www.ratwell.com/technical/FAQ.html

http://www.thesamba.com/vw/forum/viewto ... light=dual

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Amskeptic
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Re: 1972 Stock Dual Carbs -missing bits

Post by Amskeptic » Sat Nov 22, 2008 9:25 pm

Oregon72 wrote:I'm working on getting the nerve up to attempt to tune my stock dual carbs. DAMMIT!!!
Aw, we all say that.

The cutoff can be repaired if you are feeling adventurous and poor.
Are you feeling adventurous. . . and poor?

Find a male spade somewhere somehow. Notch it near where it enters the solenoid, along the edge about a millimeter from the end. This notch will allow you to insert it in the plastic hole and snag the plastic as you pivot/push the spade in. this is just a test fit. Pull it back out. Get your handy hi-performance soldering gun. Put a small vise-grip on the male spade and pre-heat it along the edge that will be going in shortly for real. As soon as your rosin core solder "melts" along the edge, cram it in the solenoid, engage your hook and pivot push the spade in firmly with the soldering iron pumping in heat. Apply a bead of solder along the flat side at the plastic border. When the solder melts, it will wick into the solenoid and probably melt the plastic a bit too. Release the soldering gun and let things cool as quickly as possible (we do not want to melt the windings inside). If the spade is holding well enough, test for correct operation. I pull the black wire to coil (+) #15, turn on the ignition, ground the body of the solenoid on the coil bracket or some other metal, touch the ignition wire terminal to the solenoid and lightly tap the plunger on the end of the solenoid. If it retracts, yer good. (you have to tap it in order for it to work. It cannot pull itself back without this little tap. Installed, the plunger has a slight preload to help it retract. Many people have condemned these things not knowing about this preload) Now get a fresh female push-on connector and crimp a 2" length of wire onto it. Put a male on the other end of the wire and plug in the wire that used to go directly to the solenoid to this male. THIS is your new plug/unplug point. When you insert the female onto the solenoid, you are going to do it with the precision of a spacewalk. It is the first and last time that the solenoid will ever take any force on the spade you just soldered.

The elbow with the nipple. Take it off the engine and clean with hot soapy water gently but thoroughly. Dry it but good. Smear it with black RTV so all the cracks are filled and a layer coats the whole mess. Let it cure overnight. The nipple needs a hose that goes from it to the INBOARD nipple on the air horn thermostatic switch. The outboard nipple on the air horn thermostatic switch goes to the preheater valve diaphram on the air cleaner intake.

Any other question o' bits?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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chitwnvw
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Post by chitwnvw » Sat Nov 22, 2008 9:58 pm

I wish JB weld would conduct electricity for just this sort of hack/surgery.

vdubyah73
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Post by vdubyah73 » Sun Nov 23, 2008 5:37 am

chitwnvw wrote:I wish JB weld would conduct electricity for just this sort of hack/surgery.
Google " lab metal " and your wish will be granted.
1/20/2013 end of an error
never owned a gun. have fired a few.

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chitwnvw
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Post by chitwnvw » Sun Nov 23, 2008 11:15 am

vdubyah73 wrote:
chitwnvw wrote:I wish JB weld would conduct electricity for just this sort of hack/surgery.
Google " lab metal " and your wish will be granted.
Hmmm.

bus71
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Post by bus71 » Sun Nov 23, 2008 12:58 pm

When you remove your solenoid, you may find that the plunger has been cut off. This is the way to "repair" it that isn"t unusual.

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Amskeptic
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Post by Amskeptic » Sun Nov 23, 2008 2:44 pm

bus71 wrote:When you remove your solenoid, you may find that the plunger has been cut off. This is the way to "repair" it that isn"t unusual.
And it is history if the plunger has been cut off.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Oregon72
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Post by Oregon72 » Sun Nov 23, 2008 4:29 pm

Colin - when you say "outboard" you are referring to the nipple on the right air horn that is closest to the right carb - 'inboard" would be the one closest to the oilbath air cleaner - is that correct?

What type of RTV is recommended? does it need to be hi-temp?

As for the central idle cutoff, I'll probably just get the one that aircooled.net has for $25.95 since I don't have a soldering iron and would need to source the right type of spade somehow - and then risk not having my hackery fix work. I'll just take it on the chin while cursing the PO's mechanic for his/her "creativity". Is there a specific type/gauge of wire I need to request for making the pilot cut-off to central idle cut-off connection.

Lotsa questions I know - sorry.

Colin hope you can save a day for me on your itinerary - '72 with no over-hatch but did I mention we have a piano?? :cheers:

Thanks,
-'72 Westy-

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Amskeptic
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Post by Amskeptic » Sun Nov 23, 2008 7:08 pm

Oregon72 wrote: Colin - when you say "outboard" you are referring to the nipple on the right air horn that is closest to the right carb - 'inboard" would be the one closest to the oilbath air cleaner - is that correct?
I am so tempted to allow you to answer that yourself. . . . . :cyclopsani:

Oregon72 wrote: What type of RTV is recommended? does it need to be hi-temp?
Ultra-black by Permatex is quite excellent. It also is a bang-up patch material for little tears in the rubber matting over the front wheel wells and for bridging gaps in weatherstrip (you impregnate the RTV as it skins with talcum powder and it acts like a brand new seal)

Oregon72 wrote: As for the central idle cutoff, I'll probably just get the one that aircooled.net has for $25.95
Good idea.
Oregon72 wrote: Colin hope you can save a day for me on your itinerary - '72 with no over-hatch but did I mention we have a piano?? :cheers:
Thanks,
I have a hatch that I did not open all summer, what with engine cases and tool boxes sitting up there, so I am familiar with dual carbs from the back only. Piano? I'm there.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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