Auto Advance Unit

Status
Not open for further replies.
WEM

WEM

Joined
Dec 8, 2017
Messages
138
Country flag
First, thanks to everyone who responded to my previous requests for assistance. Thanks to your help a 1974 Commando that had been idle for 27 years is back in operation.

I'm still running stock points and the bike runs well except for an issue with high idle that I can't get a handle on despite two new Amal Premiers and considerable tinkering. I'm thinking now that a sticking Auto Advance Unit might possibly be the issue?

From what I've read on other threads, Norton's are "famous" (infamous?) for this happening.

My questions are:
1. How do I determine if the AAU is sticking?
2. How do I lubricate the AAU if it is sticking? and
3. What should I use to lubricate the AAU? (motor oil, gear oil, grease, etc.)

Thanks again. Looking forward to the usual helpful advice.
 
The Riders Manual has a decent write up on the points setting/testing:

http://britmoto.com/manuals/Manuals/Riders_3.pdf

Since I didn't have any experience with points and there were so many other "fish to fry" learning my first vintage bike, I went straight to an EI setup (Vape-Wassell) soon after getting my '74 850 running.
 
When I still ran points sometimes the AAU would stick on full advance causing a high idle. I used nickel never-seize on the advance weight pivot pins and a drop or two of STP on the point cam lubricating felt. I also replaced the return springs whenever I replaced points and condensers. It worked well for all of the years that I ran points. Probably around 150,000 miles or so.
 
Tornado said:
The Riders Manual has a decent write up on the points setting/testing:

http://britmoto.com/manuals/Manuals/Riders_3.pdf

Since I didn't have any experience with points and there were so many other "fish to fry" learning my first vintage bike, I went straight to an EI setup (Vape-Wassell) soon after getting my '74 850 running.
Click to expand...

Believe it or not, I still have the Riders Manual that I was given when I bought my bike in 1974. Never think to look there. I'll have a look. I am considering EI but I didn't want to invest too much before I was sure I would get the bike operational. I don't think I've seen the name Vape-Wassell before. I have heard of the usual suspects: Pazon, Tri-Spark and Boyer. How does the Vape-Wassell rank?
 
The issue you are having is common if the AAU is sticking. Of course, it could also be caused if the carb slides or cable is sticking...

Assuming it's AAU related - it could be as simple as old grease that has now turned to "glue," tired or missing advance springs, worn slots in the advance plates that are causing the weights to hang up, or a combination of those.

If you are comfortable doing so and have the appropriate instructions to do it, remove the AAU mechanism and thoroughly clean all the parts in a suitable solvent. As ekasteve indicated,I would purchase a pair of new springs regardless whether the old ones are present or not. Examine the slots in the weights where the posts from the cam ride. If necessary, and if any grooves are not too deep, the slots can be cleaned up with a file or 400/600 sandpaper. If necessary the posts can be smoothed with some 600 wet/dry sandpaper. The pivot pins for the weights and the holes in the weights that mount on the pins should also be examined as well for excess play. If there was any lubricant at all, they are probably OK.

After cleanup, A drop of engine oil on each of the advance weight pivot points is sufficient. You can also use grease ...silicone grease...which used to be called distributer grease(!) is a good choice. Also put a light smear of silicone grease on the edges of the weight slots where the cam posts contact the slot.

I would be perfectly happy with running points/AAU and did it on my Commando from the time I purchased it and removed the troublesome Boyer that was on it, until I purchased a Trispark a few years later. If anything ever goes wrong with the TriSpark, I would revert to points/AAU and never look back. The biggest issue nowadays with the OEM ignition is that good quality ignition points are no longer being made. That doesn't mean what's available won't work just fine, but they won't last as long.

Good Luck!!
 
Last edited:
I ran points on my Bonneville for years with little issue except for having to adjust them every couple thousand miles. Before you loosen the points plate to get at the AAU mark the plate and case with a witness mark. Assuming the bike was close to right on timing before when you put it back you might find when you strobe it that you are very close or still right on. You can get a slide hammer that screws into the aau to pull it off or screw a longish bolt into it and tap it gently up and down and side to side to loosen it from its taper.
 
WEM said:
Believe it or not, I still have the Riders Manual that I was given when I bought my bike in 1974. Never think to look there. I'll have a look. I am considering EI but I didn't want to invest too much before I was sure I would get the bike operational. I don't think I've seen the name Vape-Wassell before. I have heard of the usual suspects: Pazon, Tri-Spark and Boyer. How does the Vape-Wassell rank?
Click to expand...
I'm a cheap-scape and always look out for bargains. The Vape-Wassell unit is a recent EI with some hardware improvements over the typical Boyer issues of having wire fractures at the pickup board connection points....the VW pickup board is fully epoxy-encapsulated. I got the whole unit for about $125 USD....and opted for new coils at same time as there was a special of $150 USD for the kit from EuroJumbayla last year. Here's the kit (same price): https://www.eurojamb.com/collection...-with-coils-by-vape-wassell-micro-mk1-a50-a65

I live close to the border so can have things shipped to a mailbox service on US side, then drive down to collect. Saves on inflated shipping rates and usually the border guards let me through unscathed with up to $200 USD or so in items.
 
Yes, change the springs. Also see if you have play in the cam to shaft. Mine was totally useless after about 4K miles, lack of lube from the PO. If you have a dwell meter put it on it and see if the dwell time stays constant. If it wanders, the shaft or cam is worn. This can be repaired with a bronze or oilite bushing, but it would probably cost more than a Pazon. The SureFire at about $125 was a godsend for me, along with sleeving the slides.
 
When I brought mine back up I dumped the AAU and went VW. The high idling disappeared as well as the pains involved with maintaining said system. The Wassell is a real good deal and pretty much a perfect drop in. As soon as this old Goldwing revival progresses a bit further I've been thinking of checking if they've one that'll fit there.
 
check timing with a strobe - if the AAU sticks you will find out. Or lock the unit with a washer in full retard and see if your high idle is gone. But I spent quite some time on correcting new Premiers with a non existent idle out of the box. Got a high idle after the usual adjustments and in the end had to take them apart and adjust float height, change the idle jets and clean out the little passages inside the idle circuit - the carbs were meant to be ready set-up for a Commando - not so. Quality is something that is not always made in GB.
 
WEAL Norton said:
check timing with a strobe - if the AAU sticks you will find out. Or lock the unit with a washer in full retard and see if your high idle is gone. But I spent quite some time on correcting new Premiers with a non existent idle out of the box. Got a high idle after the usual adjustments and in the end had to take them apart and adjust float height, change the idle jets and clean out the little passages inside the idle circuit - the carbs were meant to be ready set-up for a Commando - not so. Quality is something that is not always made in GB.
Click to expand...
Thanks to all for the suggestions. I think I'll try to have a look at the AAU as a first step. If that doesn't help, it's a little upsetting to hear that I may have to take my new Amal Premiers apart to have a look at them. in any event, no road test for a while. Wind chill here this AM is -26C.
 
My guess is the AAU especially after sitting so long. As for the Premiers, we only hear about those that needed help. My guess is that out of the thousands sold that only a few need attention. Just a guess though. Mine were perfect as were 6 of my buddies Premiers.
 
Mallory distributor grease - Bought online, little tube- noticeably improved my points follower life
and maintains dwell gap .
Auto Advance Unit


Before that tried teflon grease, wheel bearing grease, light oil, heavy oil- failed.

Your AAU needs to be removed in any case, likely no lubricant remaining on pivots. In future put a drop of oil in slot on end of shaft with it rotated to top every 500 miles- keeps shaft and bushing from eating each other
I have three 60's-70's machines with points. Start easy, idle proper, never fail
Doug
 
If it is too cold for a road test, you might consider setting up a cooling fan for your motor while messing with it in the shop. Long periods of idling are hard on them due to low oil pressure and excessive heat. The high idle will help with the oil but not the heat.
 
MexicoMike said:
The issue you are having is common if the AAU is sticking. Of course, it could also be caused if the carb slides or cable is sticking...

Assuming it's AAU related - it could be as simple as old grease that has now turned to "glue," tired or missing advance springs, worn slots in the advance plates that are causing the weights to hang up, or a combination of those.

If you are comfortable doing so and have the appropriate instructions to do it, remove the AAU mechanism and thoroughly clean all the parts in a suitable solvent. As ekasteve indicated,I would purchase a pair of new springs regardless whether the old ones are present or not. Examine the slots in the weights where the posts from the cam ride. If necessary, and if any grooves are not too deep, the slots can be cleaned up with a file or 400/600 sandpaper. If necessary the posts can be smoothed with some 600 wet/dry sandpaper. The pivot pins for the weights and the holes in the weights that mount on the pins should also be examined as well for excess play. If there was any lubricant at all, they are probably OK.

After cleanup, A drop of engine oil on each of the advance weight pivot points is sufficient. You can also use grease ...silicone grease...which used to be called distributer grease(!) is a good choice. Also put a light smear of silicone grease on the edges of the weight slots where the cam posts contact the slot.

I would be perfectly happy with running points/AAU and did it on my Commando from the time I purchased it and removed the troublesome Boyer that was on it, until I purchased a Trispark a few years later. If anything ever goes wrong with the TriSpark, I would revert to points/AAU and never look back. The biggest issue nowadays with the OEM ignition is that good quality ignition points are no longer being made. That doesn't mean what's available won't work just fine, but they won't last as long.

Good Luck!!
Click to expand...
Genuine Lucas ign points and AAU springs are available from Eurotrash Jambalaya in San Jose Ca.
 
I finally got around to pulling the points plate off to have a look at the AAU. Springs are in place and look good. No sign of anything sticking when I turn the cam by hand. However, the front bobweight actually seems too loose. The rear weight snaps back nicely when released but the front one seems to have too much slack. It moves freely when touched with no spring resistance even though the spring looks intact as far as I can see. I'm not sure what's going on here now. Just as a refresher, the initial situation that caused me to go looking was a slightly high idle that I couldn't fine tune. I installed new Amal Premiers last year so I'm assuming it's not the carbs. All carb and manifold connections are tight. Can't see any where there is an obvious vacuum leak. Any other suggestions? Thanks in advance.
 
just because the springs look good doesn't mean they are good. Replacement springs can be found. A bit of grease in the bob weight track
will help lots.
 
I have a friend who has a 750SS Ducati. To get automatic advance on it he fitted an ignition system from a Honda VT750, which was very cheap. It has Hall Effect triggers which are on the crank and took a bit of fiddling to get right. But the timing now advances up very nicely. It made a big difference to the bike. With a Commando engine, you would not need both of the Hall effect triggers as used on a V twin - only one.
 
Jackson5 said:
Genuine Lucas ign points and AAU springs are available from Eurotrash Jambalaya in San Jose Ca.
Click to expand...

Genuine Wassell Lucas. Made in Japan!

'68-'72.
https://www.britbikes.co.uk/contact...riumph-twins-1968-72-6ca---54419827-800-p.asp

Auto Advance Unit


8/10CA '73-.
https://www.britbikes.co.uk/contact...riumph-twins-1973-78-8ca---60600271-803-p.asp

I bought a set of Eurotrash 54415642 AAU springs.
They were longer than the originals and at the retarded position, slack enough to detach themselves from the spring posts until the spring hooks were re-bent to match the original spring length.

WEM said:
However, the front bobweight actually seems too loose. The rear weight snaps back nicely when released but the front one seems to have too much slack. It moves freely when touched with no spring resistance even though the spring looks intact as far as I can see. I'm not sure what's going on here now.
Click to expand...

"Front"? "Rear"? There should be two bobweights with pivots 180 degrees apart that rotate with the AAU? The springs should be strong enough to snap both bobweights back smartly when the points cam is released.
 
Last edited:
acotrel said:
I have a friend who has a 750SS Ducati. To get automatic advance on it he fitted an ignition system from a Honda VT750, which was very cheap. It has Hall Effect triggers which are on the crank and took a bit of fiddling to get right. But the timing now advances up very nicely. It made a big difference to the bike. With a Commando engine, you would not need both of the Hall effect triggers as used on a V twin - only one.
Click to expand...

http://www.jumbo-sale.com/honda-vt-...MIx-f5gJGH4QIVkg4rCh2SHwE2EAEYAyAAEgI9gfD_BwE
 
Status
Not open for further replies.
Back
Top