Basic ignition advance setup on BMW R20

[Antony]

How to setup basic ignition point/advance on R20 ? ...and what is the right one? 5 degrees?
Thanks

[Antony]

[Borgward]

ignition points (manually!) pre/ret for R20 and R23:   ~ 35° / ~ 0°

Hubi

[rolf.soler]

set it to OT (0°) and check running engine with strobe ? ± 35° with increased rpm from ~ 2500 rpm ?

[Borgward]

as the R20 has a manual ignition timing
just set the ignition to 35°vOT with the ignition lever set to "F" position.

There is no access to the flywheel for a strobe

Huibi

[rolf.soler]

sorry..

[Antony]

Thanks for reaction.
Problem is that if the ignition lever is rear position(retarded ignition)ignition point(advance)is on 15 degree.(not 0).
Question is how to change this setup?
Cam in ignition is fixed on dynamo rotor and I do not know if rotor postion is somehow fixed on crankshaft?

[Borgward]

How many degrees do you get when the lever is in the other position?

if it is around 50deg then either the rotor is not on the right position at the crankshaft or the cam is in a wrong position on the rotor. (the cam is not fixed on the rotor, after removing the screw you can take it off)

[cwf]

vOT presumably means before TDC (top dead centre) but what are the words? And is nUT the equivalent for after  BDC (bottom dead centre)? EOe is Einlassventil oeffnet and AS Auslassventil schliesst?

The French is Point Mort Haut, Point Mort Bas (TDC/BDC) and av/ap (avant/apres, before/after).

[rolf.soler]

yes 100%

[Rütz]

what are the words?

vOT : vor oberem Totpunkt
nUT : nach unterem Totpunkt

[cwf]

Ah great, thanks. Interesting that we all use 'dead' (Italian is punto morto).

[Borgward]

picture showing an R20 rotor and cam

Hubi

[Antony]

Can I see rotor(picture) from oposit side?

[Antony]

How many degrees do you get when the lever is in the other position?

if it is around 50deg then either the rotor is not on the right position at the crankshaft or the cam is in a wrong position on the rotor. (the cam is not fixed on the rotor, after removing the screw you can take it off)
......

Yes ,but "position" of cam is fixed on the rotor

[Borgward]

First check if the rotor is on its correct position, you can push it off with a (I think M14x1.0) screw. If the rotor position is ok or if you dont want to / cannot push it off you could adjust the cam by bending back the original nose and creating a new one at the proper position (see picture: blue arrow shows where the original nose was - it broke off unfortunately, red arrow shows the new nose)

good luck
Hubi

[Antony]

First check if the rotor is on its correct position, you can push it off with a (I think M14x1.0) screw. If the rotor position is ok or if you dont want to / cannot push it off you could adjust the cam by bending back the original nose and creating a new one at the proper position (see picture: blue arrow shows where the original nose was - it broke off unfortunately, red arrow shows the new nose)

good luck
Hubi

Super , thanks , now ewerything is clear for me! I will try to buy new cam? Do you have some advance? ...

[Antony]

Super , thanks , now ewerything is clear for me! I will try to buy new cam? Do you have some advance? ...

advise   

[Borgward]

it will be very hard to find that kind of cam I'm afraid

The whole ignition system is part of a
"Schwunglichtbatteriezünder F1LK" provided by Bosch which probably was also used by other motrorcycle brands. maybe this helps.

good luck
Hubi

[Antony]

Thanks, I am also thinking about replacing manual breaker plate by elektronic....