vacuum advance video


Information and questions on GL1100 Goldwings (1980-1983)
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dummysales
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vacuum advance video

Post by dummysales »



The included video link explains my dilemma. I've looked at a number of forum entries and have some basic understanding, but find the photos too small for me to identify details. If you have some directions for me based on the video below, I'd appreciate the input.



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Rambozo
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Re: vacuum advance video

Post by Rambozo »

At this point your options are limited.
Because you are still getting advance with just a hand pump, the leak is small and probably won't cause any problems right now. However, it will only get worse over time.
You can try a used part. https://www.ebay.com/itm/284055436241 But it will be just as old, so who knows how long it will last.
Depending on your skills and equipment, you could adapt an available vacuum advance canister to your bike.
You can lock out the vacuum advance and just make adjustments to the mechanical advance.
You could go with an aftermarket ignition that doesn't require it.

BTW use the share link in YouTube Studio to get a good link.


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dummysales
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Re: vacuum advance video

Post by dummysales »

Thanks for the reply info @Rambozo. I've cleaned the unit up without disturbing the canister (vacuum item that moves the interior arm connected to the advance unit) and put it back together with a cleaned up and painted cover. I'm not familiar with "locking out" the vacuum item. I presume it requires plugging the carb connection and then the canister so there's no vacuum introduced to the advance unit. True?
joecoolsuncle
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Re: vacuum advance video

Post by joecoolsuncle »

just throwing something out there,,,,,but a choke pulloff from a crburetor may be adaptable to help. think 2bbl delco, quadrajunk, autolite/fomoco, etc. it is designed to pull full travel at vacuum. they also have a slottet arm that ould be used to adjust linkage and set max advance. its free to look into. if you like that, next consider a vacuum limiter in line with the pulloff to slow the vacuum to the advance. this will allow a smoother curve into max advance.
again, just tossing something out there from long ago tuning on hot rods. then, theres the old skool manual timing /retard via cable!
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dummysales
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Re: vacuum advance video

Post by dummysales »

I appreciate the out of box idea. It’s probably out of the range of my limited mechanical ability. Thank you for suggesting it. I have a neighbor who may know what to do with the idea.
slickster
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Re: vacuum advance video

Post by slickster »

It's been awhile since I fooled around with one but I think they are supposed to bleed off vacuum slowly, as when the motor is running, there is a constant source of vacuum, at proper engine load, so the timing should stay "advanced" at the proper time..how does it run, able to check advance with light?
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dummysales
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Re: vacuum advance video

Post by dummysales »

Thanks for the reply, Slickster.

Others have noted that it will probably run for a while yet even with a hole in the diaphragm, which is apparently the case since it bleeds off immediately. This check of the vacuum has to be done with the motor out, and I'm getting it reinstalled now. Don't know if it'll run any better or worse until it's hooked up. It still has the mechanical advance unit to handle most of the chores. At 73 years of experience in life, I probably don't need the extra kick of the vacuum advance for my kind of riding, no matter how foolish I can be.

Cheers.
waj
joecoolsuncle
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Re: vacuum advance video

Post by joecoolsuncle »

the advance isnt as much an extRA KICK, AS IT IS for fuel economy, temperature, and eliminating hiccups. you need the total timing correct for the tune.
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dummysales
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Re: vacuum advance video

Post by dummysales »

Thanks, Unc. I'll consider that. Last I saw, there were no diaphragms available to fix it with. Any suggestions as to where they can be found?
waj
jasowiii
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Re: vacuum advance video

Post by jasowiii »

Hey guys,
I am putting together an '83 ater a transmission repair and just today reinstalled the advance. I was looking for info on adjustment and saw this post so I tested mine too.

It leaks down a little slower than Dummy's (maybe 3 times longer) but by no means does it hold.

I like the idea of retrofitting a more available vacuum actuator and have the fabrication capabilities to fit one but It would be a science project to get it to meet the specs (start at 40 mm/Hg and end at 80 mm/Hg for my bike) while moving the required distance.

I think I'm also gonna run it for now.
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dummysales
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Re: vacuum advance video

Post by dummysales »

Jasowiii, let me know your experience. It’d be good to have a bench mark.
joecoolsuncle
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Re: vacuum advance video

Post by joecoolsuncle »

some vacuum pods like i mentioned will have a small screw located inside to orifice the hose goes on. others have screw outside the unit. think adjustable for elevation/atmosphere, etc. on old hotrods it was common to adjust the transmission vacuum servo to enhance shift points.


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