Old, New Bonneville Cuts Out

First i would check your fuel system and make sure that the fuel tap is functioning OK (is it vacuum type?) and then move onto the ignition system.

 

The symptoms you describe are lassis (?classic!) coil failure......although it could be fuel it sounds less likely. Got a £10 multimeter?

The question is ‘which coil’? You have an ignition coil under the tank ar the headstock and a pick up coil under the Rh triangular engine side cover. You need to check resistance values/continuity on the ignition coil - 17,000 ohms plus between your HT leads. Check between low tension tabs for simple continuity. The pick up coil connector is tucked up beside the battery high behind the Rh side cover. Trace the twin wire up from its grommet near the oil inspection window. About 570 ohms.
Resistance is not foolproof as they can cool and read ‘normal’.

Let us know what you find. Ignition coil https://www.motobins.co.uk/ PVL 70506 £49.20 (as used on older BMW twins)
Pick up coil dealer only or Online OEM.

 

Congrats. With the 360 degree motor we both have it can be a toss up which coil is playing up. The 270 motor has two ignition coils and the chances of both failing simultaneously........zero!
Anyway, new skills acquired!

 

Porl.
Glad you are sorted. We need a picture of the steed.
Ride Safe & Enjoy.
Joe.