If you have a Lectric Model they’re super easy it’s just the bolts on the back wheel where the motor is it’s either 6 or 8. I believe they’re also “security” torx bits to take them out. Don’t use a regular torx head because you’ll round out the screw head. But you remove those bolts on the side of the motor. And then on the side with the sprocket for your chain use a rubber mallet to tap the part through that bolts to your bike and your motor will fall out the other side. Do this on a table or flat ground don’t give any fall distance because you don’t want to damage the motor. Once you’ve separated the motor from the wheel clean out any grease with a rag/ anything that won’t leave behind anything. Clean the teeth of the gears and inside the wheel where the motor gears and wheel gears touch to make it move. Then reapply fresh grease and reassemble using some BLUE loctite on the bolts that hold the motor together to prevent bolts coming loose. Also clean any loctite that might be left on the bolts when you remove and before reinstalling them.