Cutting is tedious. I've got to move the motor about 10mm closer to the gearbox. I've been doing this with a mix of chain drilling, jigsaw & angle grinder.
In other news, you can't cut a block of nylon with a jigsaw -- the blade heats up and melts the plastic which makes for rapid progress until you realise the material is closing behind the blade as you move forward. A hacksaw is very slow and you can't get a straight cut (well, I can't). A circular saw with a medium wood blade works quite well but you still have to wrestle with melted plastic coating the teeth.