Author Topic: Manual ignition  (Read 1461 times)

Offline townsends20

  • A's Best Friend
  • ***
  • Join Date: Apr 2011
  • Posts: 58
  • Karma: 1
Manual ignition
« on: 12.09. 2011 11:30 »

Hi all.
               Still on the road with my rgs and loving it, but after 40 years it's not the same as it was. (ma-by it's me)
Anyway I need some input riding with manual ignition as I have always been on automatic in the past. First: have I set it right? With 10.5 to1 pistons & a 375 cam, I set it fully retarded that is with the lever closed with the cable slack  at 3/8th BTC. It starts well and runs well. (still running in so taking it slow for a bit.) I need to know the best way to run it without doing any damage, I adjust the lever as I go just to take it out of the pinging zone! Is that right or is it just trial and error . Also best s/plugs to use.
              Steve.
1962 rgs

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5476
  • Karma: 64
Re: Manual ignition
« Reply #1 on: 12.09. 2011 12:20 »
Far as I know Steve ignition is set at full advance for all models, this being the position it runs at.
Retard position is for starting otherwise you get it kicking back (also retard helps on hills and limits pinking)
I don't have a RGS and never have had a manual A/R, from what you say though I would have thought cable slack was advanced
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online Triton Thrasher

  • Scotland
  • Wise & Enlightened
  • *
  • Join Date: Feb 2009
  • Posts: 1511
  • Karma: 20
Re: Manual ignition
« Reply #2 on: 12.09. 2011 12:28 »
Engine is timed at full advance.  Full advance is the lever position for normal running.  Any retarding is for starting and maybe idling or walking-speed travel.

If it's pinking, change to a lower gear, assuming you know the mixture is not weak.

Offline cotterpinkid

  • A's Best Friend
  • ***
  • Join Date: Jul 2010
  • Posts: 137
  • Karma: 2
Re: Manual ignition
« Reply #3 on: 12.09. 2011 16:22 »
Hi Steve,

Is not cable slack = fully advanced - this is correct for setting ignition timing (it's just knowing your advance from your retard).

Brian
A10 GF Plunger
Velocette Venom

Offline a10gf

  • Wise & Enlightened
  • *
  • Join Date: Sep 2006
  • Posts: 2807
  • Karma: 42
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: Manual ignition
« Reply #4 on: 12.09. 2011 18:07 »
On mine it's this:
Full advance = camring position fully ccw, control cable (lh side of cam housing) adjusted to have some minute amount of slack.
Max retard = camring fully cw. Timing to be set with ring full ccw.

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline townsends20

  • A's Best Friend
  • ***
  • Join Date: Apr 2011
  • Posts: 58
  • Karma: 1
Re: Manual ignition
« Reply #5 on: 13.09. 2011 21:50 »

Hi  I am still confused,
       I am a fag paper and pencil guy, and its always worked for me. You tell me if I have got it wrong.. With the pistons at 3/8in BTDC  the cable in slack with the points just releasing the fag paper or do I have to have the cable fully tight. (plane English please as I have been in hibernation for the last 35 years)
  Steve. :!
1962 rgs

Offline cotterpinkid

  • A's Best Friend
  • ***
  • Join Date: Jul 2010
  • Posts: 137
  • Karma: 2
Re: Manual ignition
« Reply #6 on: 13.09. 2011 22:23 »
Steve,

That sounds spot on to me  wink2

A little bit of slack in the cable ensures that the cam ring is in the fully ADVANCED position i.e. it is against the physical stop within the magneto and is not reliant on cable adjustment (in your original post you refer to this as being retarded, but it's actually ADVANCING the ignition - it's firing earlier when advanced). You should think of it in the way that you are advancing the spark (firing earlier) rather than advancing the the piston position in relation to the spark.

I've just been through an ignition timing performance with my GF. I set the timing to 30 degrees BTDC and when I strobed it the other cyclinder was firing at 25 degress (retarded in comparison). The fault lay with a badly machined repro cam ring which I've subsequently binned.

Hope this helps

Brian
A10 GF Plunger
Velocette Venom

Offline a10gf

  • Wise & Enlightened
  • *
  • Join Date: Sep 2006
  • Posts: 2807
  • Karma: 42
  • West Coast, Norway & Alpes Maritimes, France
    • A10 GF
Re: Manual ignition
« Reply #7 on: 13.09. 2011 23:48 »
Steve, to dispel any confusion: remove the mag points cover and watch the cam ring movement when actuating the lever.

camring max counter clockwise = advanced & normal running (and timing set position).
max clockwise = retard & position for starting engine (very small chance of kickback) + idling.

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Offline BSA_54A10

  • Wise & Enlightened
  • *
  • Join Date: May 2008
  • Posts: 2026
  • Karma: 32
    • BSA National
Re: Manual ignition
« Reply #8 on: 15.09. 2011 11:09 »
And remember that the advance / retard can be on either side of the maggy, so as suggested, take the points cover off.
Rotate the engine to make sure that you have the direction of rotation correct.
Now work the advance / retard lever.
When the cam ring moves in the opposite direction to the rotation of the points it is advancing the timing
The opposite is also true.
So some levers will pull to advance while others will pull to retard.
You should always check.
Bike Beesa
Trevor