Magneto Auto Advance Unit

jms

jms

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Hi All
Its me again. Just recognized the fact that my Magneto Auto Advance Unit is binding. Not throwing out and not returning. Here’s the thing, with the chain off and bolted to the mag, it operates perfectly but once you introduce the chain all bets are off. The tighter the chain the worse it is. loosen the chain and its bettet but not great. Anybody ever experience this? Think I know the answer!😜
 
Schwany said:
Try reading this if you haven't already.
TexasSlick talks magneto
Click to expand...
Schwany
Thanks for the link. I actually did a search of the forum and didn’t find this. Pretty thorough! I’m running a Joe Hunt behind the engine mag so the discussion on ramps doesn’t apply. What did apply was chain tightness. I was way too tight. I adjusted it to 1/4” and things loosened up. With the cam off the points ramp the AAU still doesn’t SNAP back from the fully advanced position as the mag cam and its bearings offers a certain amount of resistance. Instead it closes slowly. Not sure if this is normal but I guess I’ll find out
 
My error for some reason I thought you had a K2F back there. Going with the Joe Hunt is better I would imagine.

If using a 60 year old AAU with the original lube, they can be slow returning to the start position. It is possible that it will loosen up when you are under way and hot oil is being splashed all over it inside the timing housing. If the timing cover is still off, squirt some oil over it and run a heat gun at 400 degrees or more at the center it until the whole thing gets hot to the touch. That might loosen it up. Then again you could just start it up and ride it to see what happens. I wish I had that bike of yours, was single, and was 40 years younger. Oops did I say single? ;)
 
You know you can set the Joe Hunt up behind the cylinders without the AAU, you can buy a chain sprocket to fit where the AAU sits as really a Joe Hunt don't need to be retarted to fire up, set it up for full advance as the JH that is mounted off the side of the timing cover runs off the end of the cam and no AAU or magneto chain at all, my Norton fires up first kick every time at full advance without any kick back.
 
ashman said:
You know you can set the Joe Hunt up behind the cylinders without the AAU, you can buy a chain sprocket to fit where the AAU sits as really a Joe Hunt don't need to be retarted to fire up, set it up for full advance as the JH that is mounted off the side of the timing cover runs off the end of the cam and no AAU or magneto chain at all, my Norton fires up first kick every time at full advance without any kick back.
Click to expand...
Interesting. I didn’t know😳
 
I have an AAU I'm not using because I fitted an electronic Wassell ignition on my N15CS in a small housing to replace the mag, and used a simple tapered sprocket from RGM. At one point I was going to wire it solid but that was too much of a hack even for me. It seems fine, so if yours is FUBAR and you need another to try, message me.
 
gpzkat said:
I have an AAU I'm not using because I fitted an electronic Wassell ignition on my N15CS in a small housing to replace the mag, and used a simple tapered sprocket from RGM. At one point I was going to wire it solid but that was too much of a hack even for me. It seems fine, so if yours is FUBAR and you need another to try, message me.
Click to expand...
Ok thanks appreciate it. I’ll let you know
 
jms said:
Meant to ask, how's that electronic ignition working out for you?
Click to expand...
It's been perfect. It was fiddly to set up due to the location, but I got the timing just right on the first try. I went back and timed with a gun after the bike ran, and idled, and it was spot on.
 
gpzkat said:
I have an AAU I'm not using because I fitted an electronic Wassell ignition on my N15CS in a small housing to replace the mag, and used a simple tapered sprocket from RGM. At one point I was going to wire it solid but that was too much of a hack even for me. It seems fine, so if yours is FUBAR and you need another to try, message me.
Click to expand...
Getting rid of the mechanical AAU is a significant reliability improvement. There are too many wear-prone parts in the AAU.

- Knut
 
gpzkat said:
It's been perfect. It was fiddly to set up due to the location, but I got the timing just right on the first try. I went back and timed with a gun after the bike ran, and idled, and it was spot on.
Click to expand...
Nice!
 
mdt-son said:
Getting rid of the mechanical AAU is a significant reliability improvement. There are too many wear-prone parts in the AAU.

- Knut
Click to expand...
You mean just going to a sprocket and and time it for full advance?
 
jms said:
You mean just going to a sprocket and and time it for full advance?
Click to expand...
I have no experience running a bike w/out variable ignition advance. I fear violent kick-backs, and there is certainly a reason why the makers fitted them. All my magneto equipped bikes have manual or automatic advance.
If you are a mature man like me, don't risk your bones. Fit an EI or a reconditioned / new AAU.

- Knut
 
I replaced the small springs in my AAU’s before fitting. Do not buy points plate springs, they’re different. As stated, chain tension is important and I will adjust mine just enough that it’s not eating anything in the case. If you don’t use one of those plates that mimics the timing cover you’re kind of guessing chain tension once you place the timing cover.

www.rgmnorton.co.uk

INTERMEDIATE SHAFT SUPPORT PLATE TOOL (SUITABLE FOR NORTON TWINS 500CC TO 850CC)

RGM NORTON 067325 INTERMEDIATE SHAFT SUPPORT PLATE
www.rgmnorton.co.uk
 

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