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Author Topic: auto advance  (Read 602 times)
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spyke
Dorset, England
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« on: 19.01. 2011 22:45 »

Hi chaps,

Just fitted my recond mag and have now come to the auto advance unit. Im trying to avoid getting a recon unit and  was quoted 140 ish today from draganfly.
Not sure how to assess mine , i need a new fibre/ali wheel but how much slop should there be between the moving centre and the steel centre bush, how critical is the " taughtness" of the whole cabbodle to good running .I dont want to spoil the ship for a hapeth of tar  at this stage now ive completely done the motor and magneto  but  equally i dont want to replace the whole thing unnecessarily.

Cheers Spyke
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A10 spitfire style
Stu55Flash
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« Reply #1 on: 20.01. 2011 01:42 »

Spke

The auto advance is more of an on-off switch than a calibrated degree of advance mechanism. I fitted a new fiber gear wheel to mine although the rest is fairly worn it works ok. Watch out for the springs- these need to be stretched slightly when fitted rather than loose as is the case for some new springs. If loose they will come off and you may find them in the sump if your lucky or jammed elsewhere if not. I struggled to find the rivets to fit the fiber gear. Let me know if you cannot find any I have a few leftover.

Stu
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"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
Golden Flash Plunger 1955, Francis Barnett Falcon 67 1954, Ferguson TEA Tractor 1951. Looking for another project!
olev
Brisbane, Australia
A-Clairvoyant
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« Reply #2 on: 20.01. 2011 13:44 »

Stu,
I'm just about to rebuild an auto advance.
haven't been able to find rivets anywhere and thought i'd have to make them.
Please email me if you have some you will sell.
cheers
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A10Boy
Forum Oracle
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Posts: 884


Solihull, Near Birmingham England.


« Reply #3 on: 20.01. 2011 14:22 »

I have refurbished several AR units over the years and think that while there should be some, the amount of play between the inner and outer should not be excessive. The centre will be held on the mag spindle and too much play will allow the fiber pinion to move around relative to the camshaft pinion which drives it and destroy the fiber gear. I would say upto about 25 - 30 thou play on the outer edge of the fiber wheel would be ok. [in my opinion]

You need to take it apart and clean any gunge out of it before you can assess how much play you have. Sometimes they can be stuck together with crud which hides any wear. If it's in good nick, its a fairly easy job to fit a new fiber and springs.

If you want, post it to me and I will take a look at for you, [FOC], if its ok I could give it a bit of an overhaul and fit you a new fiber pinion. PM me if you like.
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Regards

Andy

1960 A10 - Black Golden Flash
1973 Z1a - Fast
1960 AJS Model 31 CSR - Beauty
A10Boy
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Solihull, Near Birmingham England.


« Reply #4 on: 28.01. 2011 15:44 »

Or not.
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Regards

Andy

1960 A10 - Black Golden Flash
1973 Z1a - Fast
1960 AJS Model 31 CSR - Beauty
JohnWB
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« Reply #5 on: 02.02. 2011 19:54 »

Andy
I also have an A&R unit that needs looking at. Is there any chance you could give it a check over & possably give it an overhaul.

I sent you an email a few days ago but I guess it got lost in the internet.

Ragards

John
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A10Boy
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Solihull, Near Birmingham England.


« Reply #6 on: 06.02. 2011 20:51 »

John
Sorry only just picked emails up. I have replied.

Regards
Andy
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Regards

Andy

1960 A10 - Black Golden Flash
1973 Z1a - Fast
1960 AJS Model 31 CSR - Beauty
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