They were assembled with great attention to detail, each fitting (stock) has the appropriate spacers lock washers etc, when people start losing them or hack them is when they have issues. Not had my 50v apart much, but took my "7" partially apart last summer and was amazed at all the little pieces parts, just have to lay them out in order they were removed, (I have a bad memory) but if you put them back as they came apart it will be fine, a good grease gun is needed for the variator and pedal shaft, also leave the pedal/engine switch alone!!! The internals of the driven pulley can rust up, and if you get it out of engine mode it can be a real bitch to get back. If you must pedal the bike push the engine back and slip the belt, very easy, but you don't want to pedal one other than to start it anyway, too heavy and geared too low, you can walk it faster.