There's never a need to have a car running if jumping a Motorcycle and as you've found out it can ruin components on the Motorcycle.If the extra passive power from the larger Car battery won't start the machine then starting the Donor car won't help.The fault on the Motorcycle needs to be fixed.
Because the internal resistance of the Motorcycle battery will be lower than the Donor battery as it has been depleted the extra current from the Alternator on the car will bypass it's own battery and shunt the current to the smaller and much less robust Motorcycle battery.The danger to the Motorcycle electrics will increase further if the Donor car is revved up
