Vacuum thingy beside gas cap


Information and questions on GL1100 Goldwings (1980-1983)
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idjit
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Vacuum thingy beside gas cap

Postby idjit » Sun Mar 13, 2011 3:51 pm



I was testing my vacuum advance and there was a leak, but I discovered it was not the advance, but this strange thing by the gas cap. I've always wondered what it is.

The vacuum hose on #3 goes to a "T" and then to both the vacuum advance and this "thing". I'm left wondering if it is
purpose could be to draw fumes from the false cover area and perhaps normal to have some draw through it?

Please advice as I don't know if I should block it off or not.

Thanks !! -Bob



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littlebeaver
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Re: Vacuum thingy beside gas cap

Postby littlebeaver » Mon Mar 14, 2011 10:14 am

It should not have a T in that line. I wonder what that's about..

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Mon Mar 14, 2011 10:27 am

Yes, and the "T" has a pinhole sized passage to this device. It's a 1980, maybe its peculiar to that year. The device is attached to the cross member of the false tank with a 10mm bolt. From memory, it's black and probably about 2-1/2 inches square and about 3/4 wide. From the way it's mounted, it certainly looks stock to me.

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littlebeaver
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Re: Vacuum thingy beside gas cap

Postby littlebeaver » Mon Mar 14, 2011 10:51 am

I don't know about it, mine is a 81 and doesn't have that, and i checked the schematic's for the 80 model and it shows a straight hose, I could be wrong and it certainly wouldn't be the first time, if it looks stock then it probably is..I wonder if anyone else has that T like that..Cool information for sure..

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WingAdmin
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Re: Vacuum thingy beside gas cap

Postby WingAdmin » Mon Mar 14, 2011 10:55 am

Any chance you can post a picture of it?

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Mon Mar 14, 2011 11:01 am

Well this is just getting interesting. Maybe it's a smoke ventilator for an optional ash tray that would have been mounted beside the gas cap. Lot's of people smoked in the '80's. HaHa.

I will snap a couple of pictures tonight so that even if it is identified by someone by the time I post them, you'll know what it looks like. -Thanks!

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Mon Mar 14, 2011 5:31 pm

Note the small pinhole to the device. It must be meant to minimize the air flow.
Note the small pinhole to the device. It must be meant to minimize the air flow.
Attachments
Here it is mounted in the bike. (Note what 2 days in vinegar does to a really dirty old rusty gas cap. The dot was a spot of red paint that I flicked off afterwards before drying and treating with WD40.)
Here it is mounted in the bike. (Note what 2 days in vinegar does to a really dirty old rusty gas cap. The dot was a spot of red paint that I flicked off afterwards before drying and treating with WD40.)
And here it is pulled aside to show the intake at the bottom.
And here it is pulled aside to show the intake at the bottom.

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WingAdmin
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Re: Vacuum thingy beside gas cap

Postby WingAdmin » Mon Mar 14, 2011 9:39 pm

I looked through two different GL1100 parts manuals, and just for good measure I checked a GL1200 manual as well (just in case you have a Frankenbike). I didn't find ANYTHING that looks like that.

My best guess is that it is a vacuum reservoir - that's what it looks like to me. However, even on the GL1200 that DOES have a vacuum reservoir (for factory cruise control), it doesn't look like that - it's in relatively the same position, but it's cylindrical.

The thing should have numbers of some kind molded into the plastic that might help identifying it - can you see any?

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guitarlos
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Re: Vacuum thingy beside gas cap

Postby guitarlos » Tue Mar 15, 2011 5:25 am

I have the same thing on my Gl1100 and I havent had it installed for one year now and the bike still runs the same. I have no idea as to what it is. Extra parts? ;)

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Tue Mar 15, 2011 6:51 am

No Part Number. It has "Tec-A" or "Tel-A" stamped on it. It's difficult to make out cause the part before the "-A" is a logo with the top of the T extending across the other two letters and a strange font that makes it difficult to be sure is it's a "C" or an "L".

I tried sucking air through with the entrance hole covered and couldn't. I still think it's for fumes and perhaps a charcoal substance in it would explain it's size. The restrictive "T" connection probably keeps the flow down enough to prevent a lean condition in #3. I think the reason no one has seen it is probably because it's a Canadian add-on. Of course this is all just a guess, but why would anyone throw such a strange looking thing into the mix without a reason.

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Tue Mar 15, 2011 6:59 am

Hey Guitarlos,,

What year is your bike? Any chance it originated in Canada? Maybe they both originated in California. I don't know how I would know for sure.

That would make sense. In the Late 70's the VW' Bus's in California had Catalytic converters.

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WingAdmin
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Re: Vacuum thingy beside gas cap

Postby WingAdmin » Tue Mar 15, 2011 7:46 am

idjit wrote:No Part Number. It has "Tec-A" or "Tel-A" stamped on it. It's difficult to make out cause the part before the "-A" is a logo with the top of the T extending across the other two letters and a strange font that makes it difficult to be sure is it's a "C" or an "L".

I tried sucking air through with the entrance hole covered and couldn't. I still think it's for fumes and perhaps a charcoal substance in it would explain it's size. The restrictive "T" connection probably keeps the flow down enough to prevent a lean condition in #3. I think the reason no one has seen it is probably because it's a Canadian add-on. Of course this is all just a guess, but why would anyone throw such a strange looking thing into the mix without a reason.


If it does in fact have charcoal in it, then for sure that's what it is - it will be intended to gently suck up and absorb any gasoline fumes that are released by the gas cap, rather than let them out into the atmosphere. If that's the case, it's an emissions device, and thus can be safely removed and the hose clamped off with no ill effects (to the motorcycle). :)

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littlebeaver
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Re: Vacuum thingy beside gas cap

Postby littlebeaver » Tue Mar 15, 2011 1:06 pm

Frankinbike ha ha, that made me laugh out loud, I find this to be very cool, another guy has some rare engine cover's, I have messed around with these vacuum advances for a while now and I don't see a problem with having that T or pin hole there at all, the suction from the carb should be more than enough to supply plenty of vacuum to open the advance up with no issue's still, it's when the canister or diaphragm in the canister has holes in it, that's when you lose your vacuum advance..It will run without it but who wants that? You have yourself a unique bike..Cool Post......Frankinbike :lol:

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Tue Mar 15, 2011 4:15 pm

Yup, but you'd want to plug off the hose at #3 to prevent a lean condition.

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littlebeaver
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Re: Vacuum thingy beside gas cap

Postby littlebeaver » Tue Mar 15, 2011 5:33 pm

Not me, I rebuild vacuum advances, never..

idjit
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Re: Vacuum thingy beside gas cap

Postby idjit » Tue Mar 15, 2011 7:17 pm

Well, that would be my choice too, but I read they were unobtainable. It hadn't occured to me that they could be refurbished. Mine's fine, but do you this for others?

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littlebeaver
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Re: Vacuum thingy beside gas cap

Postby littlebeaver » Tue Mar 15, 2011 7:33 pm

idjit wrote:Well, that would be my choice too, but I read they were unobtainable. It hadn't occured to me that they could be refurbished. Mine's fine, but do you this for others?

I took a vacuum advance for a automobile and modified it to make it work...fun project..mine won't leak for many years to come.. :D




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