auto advance question

[mike667]

Hey gang
 so while/ when trying to adjust the magneto / timing i notice that after i tighten up the bolt securing the auto advance unit to the magneto the auto advance springs doesn't  snap shut -  seems like its sticking so wondering if i can something mucked up while tightening it down (it closes up fine when off the spindle etc)

any thoughts?
 thanks as always!

mike

[bsa- bill]

HI Mike - glad you asked this one as my project does the same, I swapped the AAR unit with one off my flash that I know works - no change, so I'm thinking the problem maybe lies with the Maggie shaft maybe
Possible it might free up with use.
Looking forward to to some answers

All the best - Bill

[MG]

Hi Mike and Bill,

I also noticed that on mine,  I think this is caused by the friction in the magneto shaft (mainly points, magnetic field, maybe bearings).
Once mounted, the pinion can't trun freely anymore naturally as it is engaged with the other pinions down to the crankshaft, and the maggy shaft is held by friction (if it wasn't, you had no chance of mounting the AAU I guess).
Just turn the engine over a bit and you will see the AAU closing almost immediately. When I checked timing I also saw it working properly, so nothing to worry about.

Cheers, Markus

[Rusty nuts]

Me three!

I switched to one procured from evil bay.
Still sticks, but not as much as the first which leads me to suspect units themselves rather than magneto shaft.
Also my mag newly overhauled by Dave Lindsay so doubt prob there.

Both seem to work fine & no performance difference between them.
But then my poor old longstroke is still struggling to get past 50 mph but that's another story!

Rusty

[mike667]

Hi Mike and Bill,

I also noticed that on mine,  I think this is caused by the friction in the magneto shaft (mainly points, magnetic field, maybe bearings).
Once mounted, the pinion can't trun freely anymore naturally as it is engaged with the other pinions down to the crankshaft, and the maggy shaft is held by friction (if it wasn't, you had no chance of mounting the AAU I guess).
Just turn the engine over a bit and you will see the AAU closing almost immediately. When I checked timing I also saw it working properly, so nothing to worry about.

Cheers, Markus

Markus as per usual you are the man - thanks!

[Triton Thrasher]

Check that you have backlash between the teeth of the two pinions.  Lack thereof can cause the stiffness when you tighten the nut.

[beezalex]

Guys, as far as I know the sticking is normal, mainly because of brush and cam follower friction.  When the mag is rotating, the cam ring shoe friction always tends to make the AAU retard until the centrifugal force is high enough to pull the weights out.  IOW, don't worry, unless it's stuck tight.