Vacuum Advance questions


Information and questions on GL1100 Goldwings (1980-1983)
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cbach1981
Posts: 154
Joined: Sun Mar 14, 2010 9:03 pm
Location: Salem, ME
Motorcycle: 1983 GL1100I Interstate

Vacuum Advance questions

Postby cbach1981 » Sun Jun 03, 2012 10:51 am



Hey guys, a quick question or two for you. I recently purchased a mity-vac to test my vacuum advance unit. I found a post stating that the unit should hold at approx. 3.8" after bleeding off any excess vacuum. Mine doesn't bleed off at all. I've placed it all the way to 25" on the mity-vac guage and it holds firm right where I stop pumping. Seems to be working fine, the engine idles up when I activate it. so is it ok that it doesn't bleed off? or might that cause some sort of issue?
My other question is how much vacuum should you measure on the tube on number 3 carb? Mine hits around 5" when I hit the throttle a little. Good number or not? Any info will be appreciated, thanks!


    You only need two tools in life - wd-40 and duct tape. If it doesn't move and should, use the wd-40. If it shouldn't move and does, use the duct tape!

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littlebeaver
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Re: Vacuum Advance questions

Postby littlebeaver » Wed Jun 06, 2012 1:43 am

Yes its fine, it sounds like you are just pumping it too much, it should just take one pump, if it's holding a vacuum and not bleeding down that means the diaphragm has no leak but maybe its sticking inside, it can be adjusted but it will take patience, there's a cap on the rear of the canister that seals the adjusting screw[epoxy], you remove that and there's a screw down in that hole, turn it in and the numbers will raise up back the screw out and the numbers will drop[factory set], air will leak out of that hole so you have to hold it or cover the hole while your testing it and re seal it when your done..If you are hearing a snap back sound when you release the vacuum I wouldn't fudge with it.. 3.8 should be the highest point at full throttle the vacuum advance is wide open at about 3grand..

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virgilmobile
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Re: Vacuum Advance questions

Postby virgilmobile » Wed Jun 06, 2012 7:07 am

Like littlebeaver said.Everything is just right.don't fix it.

Is this just a look see or are you having issues and your poking at it.?

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littlebeaver
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Re: Vacuum Advance questions

Postby littlebeaver » Wed Jun 06, 2012 10:20 am

Cbach81 here is a video I took showing how these vacuum advances will bleed off air down to the correct setting and I'm going to post what the rear part of the cannister hole looks like uncovered..But here's the video then the photo..



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littlebeaver
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Re: Vacuum Advance questions

Postby littlebeaver » Wed Jun 06, 2012 10:23 am

Here is a photo of the cannister and the rear of it where you can remove the epoxy cover to make adjustments if you absolutely feel you need to, I'd leave it alone though..I have played around with these advances trying to learn and figure them out and I feel I have done a pretty good job at it..
Oh for anyone that doesn't have a epoxy cover over that screw hole you really need to cover it with some expoxy and or jb weld..air will leak out there for sure 100 percent for sure.. :D I'd place a small spitball in the hole so the epoxy doesn't bond to the screwhead or dribble down into the hole..Cbach what I'm saying is this, I can make mine go up to 5" too if I wanted to.. :lol:

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eklimek
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Re: Vacuum Advance questions

Postby eklimek » Wed Jun 06, 2012 12:05 pm

little beaver

You've been there. What is the easiest to remove and reinstall the vacuum advance unit?

PM me if you want.

Ed

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littlebeaver
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Re: Vacuum Advance questions

Postby littlebeaver » Wed Jun 06, 2012 12:37 pm

Yes, I have removed the pg a few times, I would tell you this, it's a pain in the butt but once you do it, it's gravy the next time, remove shocks or bolts to the swingarm, heck I just pull the whole shock, remove rear wheel, swingarm comes out :shock: , need to make or get a special tool for the battery side locking bolt at the swingarm :shock: , it's probably best to jack the bike up as high as possible, of course my roll up stand is perfect for this work :geek: ..I think I removed the brake MC too, and once you get the swingarm out of the freakin way, then remove the bolts to the cover of the pg, make sure to place a piece of tape on the cover and put an up arrow on it so it goes right back on the way it came off, now remove the smaller bolts inside the cover, now one of these[lowerleft] does not have a washer take note of that bolt so when you put it back you know which one doesn't have a washer, the reason it doesn't is because if it did the base plate would collide with it..Pull off the the unit and gasket, I'd remove the spark unit and clean it up and inspect the ball bearings on the inside rear of the unit , clean it up with brake cleaner and lightly grease all moving parts on the spark unit..Mine was pretty gruddy..My advance was all jacked up..Vacuum didn't work, plate was all stuck and such..Major difference once I cleaned and set my pg FREE :lol: ..It was all happy again. :lol: . :lol: One word of advice, if you guy's ever remove the arm to the vacuum advance, do not spin the arm threads, if you do it will advance the timing or retard it...Look on the canister itself once you remove it, see that arrow on it, well when you remove the side set screw you can spin that canister once or twice if needed to set the timing if it's off, you would need a timing sight cap or inspection cap for that..These arms are factory set and I wouldn't fudge with it unless you have to..Anyway everything goes back the way it came off, good luck to you guy's.. oh here's another video of my vacuum advance in action...it happens to be one I made from an automobile....Yes I modified a vacuum advance from an auto mobile...You can do anything if you set your mind to it..

I hope you guy's get something out of this..

cbach1981
Posts: 154
Joined: Sun Mar 14, 2010 9:03 pm
Location: Salem, ME
Motorcycle: 1983 GL1100I Interstate

Re: Vacuum Advance questions

Postby cbach1981 » Wed Jun 06, 2012 5:08 pm

Littlebeaver, thanks for the replys and in depth info on the vacuum advance. I know that it only takes one pump to get above the 3.8, i just pumped more to see if added pressure would bleed off. It doesn't. As long as it's not going to blow something up, i'm not gonna mess with it. especially during riding season!!
    You only need two tools in life - wd-40 and duct tape. If it doesn't move and should, use the wd-40. If it shouldn't move and does, use the duct tape!

User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: Vacuum Advance questions

Postby littlebeaver » Wed Jun 06, 2012 5:17 pm

Your fine man, it's the least I could do for a guy that has helped so many out with the link to the manuals..Oh if you notice in the video, my needle goes up around 5" then drops, what is happening with yours, is the setting of the diaphragm in the canister is set down further for some strange reason..The main thing is this, you are getting your vacuum advance that's for sure..Your good to go man..Ya know, I screw around alot on this site but I do have a little to offer at times.. :D




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