Missing spring on Auto Advance/retard

[Andy51]

Hi All, I couldn't start my '54 18S with SR1 mag this morning (although I could get a few bangs out of the engine, it wouldn't run and kicked back a lot) and after my neighbour and I spent some time looking for the fault and eliminating the obvious, the only thing we could think was that the timing had somehow slipped. Took off the magneto drive cover and saw that one spring was missing from the auto advance/retard mech. Nothing dropped out when I took cover off, and nothing in chaincase or behind sprockets. The mech appears jammed as I cannot rotate the moving part that is controlled by the springs and weights - I seem to recall this can be turned a bit and is held open by a wooden peg when setting timing. So, 3 questions: would this cause the starting problem; where could the spring be lurking; and does anyone stock the offending springs (club has no stock). Thanks, Andy

[clive]

In my experience the auto advance will not move if the chain is too tight however in the case of a disappearing spring it could well be jammed inside the mechanism. Cannot help with a supplier for the springs except the usual AMC spares or Russel motors.

[Rob Harknett]

The kick backing is due to the AR being jammed fully advanced. This needs to be cleaned out. It can be done without taking the AR unit off. Flush it with white spirit or the likes working the unit by hand. May be difficult to move at first. As you work it white spirit will look rusty. Keep work until it clears. You will find when springs are fitted, if lost. The unit will snap back closed in the retard position. Note also what Clive has stated about the chain being too tight.
Have you a picture of the AR unit. You may have a type intended for a different marque. You can clearly see springs and where they fit on AMC type.

[raffles]

Andy
Ihave a couple of springs that may do the job I cant remember exactly what they are off of but they are
certainly advance and retard.
Let me know and I will send you them. You will have to remove and wash out your A&R to free it up
and to find your missing spring
Tony

[G15 Roy]

Do you have a part number for the spring? as we have just had some auto advance springs made and if we don't have the one you want i am sure we can get them.

[Rob Harknett]

Do you have a part number for the spring? as we have just had some auto advance springs made and if we don't have the one you want i am sure we can get them.

Ashampoo_Snap_23 October 2019_19h54m39s_004_.jpg

From 1955 parts list Roy. I was not aware springs differed on 350 & 500.

[Andy51]

Hi, parts list for 1954 does not list ATD springs, but Rob's extract is from 1955 so will be applicable. Jampot Spares list part no 416060, which is same Lucas part no as on Brightsparks website. Currently out of stock, due in 15 Sep. Any news? For the moment I can cannibalise from my G80, but will need spare springs sometime. Thanks for your help, Andy

[Rob Harknett]

Hi, parts list for 1954 does not list ATD springs, but Rob's extract is from 1955 so will be applicable. Jampot Spares list part no 416060, which is same Lucas part no as on Brightsparks website. Currently out of stock, due in 15 Sep. Any news? For the moment I can cannibalise from my G80, but will need spare springs sometime. Thanks for your help, Andy

In 1954 only the 500's had the SR1 mag. 54 parts list only gives points and sprocket part numbers. Note that 350 & 500 springs have different part numbers in the 55 list..

[Andy51]

Just removed offending ATD. No sign of missing spring, but it was definitely seized. I partially freed it up, but it is still very stiff. Is this normal? No obvious rust, still covered in grease from when I fitted it over 10 years ago. It is soaking overnight in white spirit to clean grease and crud off, then I plan to give it a good spray with penetrating fluid - grateful for ideas/comments. Thanks, Andy

[Rob Harknett]

Just removed offending ATD. No sign of missing spring, but it was definitely seized. I partially freed it up, but it is still very stiff. Is this normal? No obvious rust, still covered in grease from when I fitted it over 10 years ago. It is soaking overnight in white spirit to clean grease and crud off, then I plan to give it a good spray with penetrating fluid - grateful for ideas/comments. Thanks, Andy

It gets rusty inside where you cannot see. Wrap you fore finger into your finger and thumb. You can turn your fore finger if its not gripped too tight. grip it tight and you cant turn your finger. Rust is making your AR tight in the same way as you are doing when tightening your grip on your fore finger.
So where these surfaces rub needs cleaning. So just keep working the AR unit by hand until it free's off. You no need to dismantle anything to do this.
Probably easier if its on the bike. You only have to grab the unit and keep open and closing it. When you open let go and it snap back, its free. If of cause you have it completely fitted with its springs. Grease will probably not get in where it rusts. so when it needs cleaning because its sticking open. Your bike will tell you so. It will kick back and be a pig to start, perhaps cut out when you shut down till the engine warms up. Old boy showed me that years ago when I was a teen. My bike always started first kick. The old boy see me one day trying to start the bike. He asked if I'd been missing about with it. I said no, suddenly it starting to kick back a lot. He griped his finger as I have just said about, to try and show me what was happening due to rust. So he kept his hands clean and told me what to do to free it off.