BMW R25/3 IGNITION PROBLEMS

[Thomas]

Hi,I just finish with the restoration of my bike but i have ignition problems.The engine starts easy and works nice on low rpm but when i increase the rpm the engine stops.Even if i manage to increase the rpms without engine stop,then it starts to backfire on the exaust and carburator.I have adjust the contacts to open on the mark "S" of the flywheel (thats 5degrees before the top dead end)and doublecheck everythink but the problems go on.Few days ago i had the first tests of the bike on the road and everythink working ok then.I took her to about 60km/h so im sure that the valve/camshaft adjustmens are ok.Any ideas what may go wrong or what else i have to check?

[Chen Kalmanovich]

Check the carburator, main jet and fuel level.

[Thomas]

Yes i think you right because now that i remember ,my bike before the restoration was working with a honda or somethink like that air filter and after the restoration i done the first tests without filter but i couldnd open the throttle more than one third.The last test i done was with the original filter under the tank .So i will try a bigger jet to see what will hapen

[erwin]

you should check the alternator, maybe it's magnet has gone very weak that it caan't produce much electric current. that why when u increases RPM it stalls

[Thomas]

I dont think so because before the restoration the bike was running good without problems.

[Alan Davies]

Hi,
I had the same problem, after the winter lay-off I found my battery was not fully charging, bought a brand new high capacity battery, probem solved!
Alan