Vacuum advance and pluse generator (VACUUM ADVANCE REBUILD)

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danf

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I got the cover off, nothing moves when sucking air, I need help, I have a manual and it says remove the vacuum advance tube, is that in the center of the pulse generator with the bolt on it?
 
"Vacuum advance tube" probably means the hose . When you apply vacuum to the hose does it hold vacuum or leak off? If it holds vacuum things may just need to be freed up and lubed. If the vacuum can is leaking you need to replace the assembly, it isn't available separately.
 
if you suck on the tube and it dont move the ignition plate that the ignition moduals are on then it not working....but make sur you test it with a new hose as to eliminate the hose as being the bad part....the bike is old and the vacume advance is only good for a million or so moves it just may be done ....if it is i would block off the vacume from the carb i think it is on the other end and go with it the way it is ....there is also machanical advance to on it too and your not going to loose much by blocking it off and relieing on the machanical advance only ....unless your willing to spend the money and time to fix it up to work again ....ithink new parts are non existent ......if it running bad i cant see this being the major cause unless the machanical advance is not working for some reason too.... :mrgreen:
 
Is sucking on this with your mouth a good test? I'm just askin, cause I don't know. Seems like it would take more than that to get the plate to move. Then again, some might just suck more than others! :smilie_happy: (No offense to anyone...just joking!)
How much vacuum does it take to actually move the adv. plate, anyway? Automotive cans usually require about 10>" of vacuum to move them.... :headscratch:
 
im not sure as ive never done this but ive herd several people say this is the test apple .....and that it seem more a problem about stopping the leaking vacume....nothing i have any time in doing :smilie_happy: :smilie_happy: :mrgreen:
 
joedrum":2yio9q04 said:
im not sure as ive never done this but ive herd several people say this is the test apple .....and that it seem more a problem about stopping the leaking vacume....nothing i have any time in doing :smilie_happy: :smilie_happy: :mrgreen:
Yes sir, I have removed the rear wheel, brakes, shocks, swingarm and it's easy to access from the rear, I'm going to fix this thing because its not working proper, I used a mittyvac vacuum to test and its not moving anything and not holding a vacuum, it was missing a bolt on the cover to..It's time to operate.. :eek:
 
beaver if you got the cover and back wheel id fix it to ...that plate ought to be free to move some that the vacume arm is hook to and the ignition moduals sould be hook to it.....just so you will know if your 1100 is an 82-83 you can adjust the timing by loosing the bolt that crimps the vacume housing ...it will rotate in and out by threading on the threaded linkage to the plate on the inside part .....it might be something to mess with to fine tune the ignition .....im diffinitly going to try this on my 82 1100 with the 75 1000 cams to see if i can find a sweetspot for the parts mixing i did .....i think the 80-81 are crimp together with a rivet that could be modify to adjust ......i dont know if you can buy anything from honda to fix it but im not sure .....e-bay might be the only way and thats a gamble on something like this .... anyway i think thats all i know good luck beaver :mrgreen:
 
Hey Joe Thanks Man, If fixed the unit, I was unsure about that center bolt and shaft, now I know, I removed the housing for the unit leaving the center shaft alone, I found that the base plate was rusted shut and didn't pivot side to side at all, I sprayed the baseplate with brake cleaner to free it from the housing and removed it, I then cleaned up with more spray, there are many ball bearings on the backside, then I sprayed with WD-40 until it looked cleaned up, I then used some 3 in 1 oil and oiled real well, put it all back together and it moved now when sucking on the hose and it holds too. Most Awesome..I'm happy now..Can't wait to see the difference, just because it doesn't hold air doesn't mean it's broken or not good, clean it and then try it.... :grin:
 
littlebeaver":3nykdrqb said:
Hey Joe Thanks Man, If fixed the unit, I was unsure about that center bolt and shaft, now I know, I removed the housing for the unit leaving the center shaft alone, I found that the base plate was rusted shut and didn't pivot side to side at all, I sprayed the baseplate with brake cleaner to free it from the housing and removed it, I then cleaned up with more spray, there are many ball bearings on the backside, then I sprayed with WD-40 until it looked cleaned up, I then used some 3 in 1 oil and oiled real well, put it all back together and it moved now when sucking on the hose and it holds too. Most Awesome..I'm happy now..Can't wait to see the difference, just because it doesn't hold air doesn't mean it's broken or not good, clean it and then try it.... :grin:
After further testing I found it is still not holding a vacuum, but everything moves when sucking air hose, but it's foolish to put it back on if it's leaking air still, I have a friend with another vacuum advance unit that's good and holds a vacuum, I will change out tomorrow.. and I am going to try to fix the one that's leaking air and figure out why they leak ect. by dismantling the unit..If I fix one I will share my findings..
 
joedrum":2cuhhgm4 said:
im not sure as ive never done this but ive herd several people say this is the test apple .....and that it seem more a problem about stopping the leaking vacume....nothing i have any time in doing :smilie_happy: :smilie_happy: :mrgreen:
Joe I find that, that is the case, however the baseplate will lock up, once cleaned up the baseplate should move easily with just sucking the hose, but if it doesn't stay open while sucking air the advance diaphram in the unit is bad and should be replaced...I'll fix it . or figure out something....I'm stubborn that way..
 
I wasn't the one who designed the system so can't say for certain but. The motor is constantly creating vacuum at different levels matching rpm. Therefore any bleeding at the advance is of little consequence and allows it to move quickly to the present level. If there were no leakage at the advance the motor would have to both push and pull by vacuum. Seems an unlikely thing to me. :hi:
 
slabghost":1g63kh9r said:
I wasn't the one who designed the system so can't say for certain but. The motor is constantly creating vacuum at different levels matching rpm. Therefore any bleeding at the advance is of little consequence and allows it to move quickly to the present level. If there were no leakage at the advance the motor would have to both push and pull by vacuum. Seems an unlikely thing to me. :hi:
Oh man you should have seen the rust and crap that came out of the back of the base plate. I was curious about the advance unit because I read about it and I didn't hear any click while sucking on the hose and it didn't hold a vacuum, the bike runs good and all to date, but I wanted to see if anything was wrong and it was..Wow..Surprise surprise..It will probably run even better once repaired and back on.. Cool, but it's some work removing everything..
 
slabghost":3j5r6wkh said:
I wasn't the one who designed the system so can't say for certain but. The motor is constantly creating vacuum at different levels matching rpm. Therefore any bleeding at the advance is of little consequence and allows it to move quickly to the present level. If there were no leakage at the advance the motor would have to both push and pull by vacuum. Seems an unlikely thing to me. :hi:

As I understand the way an advance works, the diaphragm is under some constant spring pressure trying to pull it back.
The vacuum pulls against that spring so when the vacuum lessens so does the advance.

Mine leaks also.
There was a discussion way back about this and I think everyone who checked said the same.
I don't know if they are designed to leak but I did open one up and the rubber looked in perfect condition.
The only place I could see would leak is where the 2 metal halves are crimped together.

I'm interested to hear if the one from beavs friend leaks by.
 
I'm taking my mittyvac with me and I will test it before I give him twenty bucks for it..I am thinking if there is a leak at the sides then a good easy fix would be to seal it with JB Weld..Clean all the oils and grease off the housing first.. How did you open it Dan.??
 
If I remember correctly the vac advance units on the cars back in the day all had the leak. There was a tiny hole drilled in one of the halves.
 
Thank you guys, every little bit of information is helpful, does anyone know what the set screw is for in the center of the unit on the end, over by the air hose directly in line with the arm shaft that goes into the unit..? It appears to be some adjusting screw..
 
that is where i was telling you ....you can adjust the timing with.....if you loosen that bolt you can turn the whole unit and it will move the ignition plate ....as ive said before you might want to fine tune it there .....pretty neat deal .....most think that the timing cant be adjusted.....so did i ....but it can be....if you mess with it just make sure you mark it in a way to know where you started ....one complete turn dosnt move it that far and very accurate ..... :mrgreen: good luck today beaver :builder: :mrgreen: seems like your going to be an expert on this before the day is done :mrgreen:
 
It's been awhile and don't remember how I opened it but something like that knowing me it was either working a flat screw driver under the lip and prying up or somehow or another a dremel was involved.
Either way it wasn't salvageable afterword.
 
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