Join Date: Sep 2008
Location: Honolulu, HI, USA
Did you buy a red K13one back from Jacob T? Almost bought it, sorry I hesitated just a few days too long.
First and always, have you used the search function on this or other sites?
Handlebar switches can be problematic. There are several things you could try, but generally you want to discern whether it's the switch, the motor, windshield mechanical linkage, or "something else".
Does the shield go up and down smoothly, when it works? If so we can omit further consideration of the mechanical linkage. You could also disengage it from the motor to confirm smooth operation.
To check the switch, can you put a test light or multimeter on the wires from switch to motor and see (when the shield isn't working) whether the switch is sending power to the motor? That would confirm or exonerate the switch.
To test the motor... whack it when it doesn't want to behave and see if it responds then. If it's the motor that is cranky, disassembly or replacement would seem to be your only options. How are your mechanical skills?
You could just live with it. Worse things have happened to Kbike owners. IIRC (and if this is the bike I rode) the shield is aftermarket and larger than stock. Was it correctly installed or somehow subject to jamming. Worked when I rode it. Can't be more than one K13gt in Pahoa nor likely others in all Hawaii.