Running Problems

[trikemaste]

1966 BSA 500 twin. stopping running. left coil gets very hot. replaced left coil still gets hot. right side fine. stumped thanks

 

[DaveM]

Hello and welcome to the forum

 

[grandpaul]

Welcome to the forum.

A50, eh? Points or electronic ignition?

Check all wiring connections, clean & adjust points as a start...

The fact that a new replacement gets hot points to the circuit it's connected to. Are you sure both coils are the same exact make/model/rating?

 

[Rudie]

replaced left coil still gets hot.

If using points:-

. Are the left points closed? If they are, with the ignition switched on, there is a complete electrical circuit through the left coil and it'll get hot if the engine isn't running.

. If the coil still gets hot even with the points open:-

.. Does the bike still have the crap 4CA points plate, with the condensers (cylindrical things) mounted on the plate?

.. If the bike has the later 6CA points plate and condensers mounted separately on the bike, disconnect the wire to the left condenser; does the coil still get hot? If not, the condenser's died closed.

Do you have access to an Ohm- or multi-meter?

If a multi-meter, set the scale to read Ohms (might be indicated by a horseshoe-shaped symbol).

Meter leads connected to meter, press one end of one lead on to each coil screw terminal; if the meter reads between 3 and 4 (Ohms), the coil is a '12V' one; if the meter reads between 1.5 and 2 Ohms, the coil is a '6V' one. '6V' coil is only correct if the bike has 6V electrics or an electronic ignition and 12V electrics. Anything else is wrong.