Just taken possession of a Pantah 600 and it's come from storage without a battery. I understand 14AH is the recommended size but most of the batteries of this power seem to be 135mm long and the rubber battery base appears to be only 120mm long. Any advice or suggestions would be welcome.
The choices are remove the rubber battery base (cut off the ends?) or see if you can find a slightly smaller 12 amp battery that fits. I wouldn’t go lithium, because I doubt if the bikes charging system is suitable.
I restored a 500SL Pantah a few years ago and used a MotoBatt MBTX14AU. I had no problems fitting it.