The seal does not effect the electric system but Peugeos with a good spark and engine problems may want to look into it. If the Seal fails air and or fuel will leak out, my bike is continualy overheating and it is timed to perfection. So the problem lies in what makes an engine overheat, lean fuel mix will do it and I know this is my problem, so why is it lean? a leaking crank seal will do this, it alows air to enter throught the seal and lean the mix. This is esecialy true with Reed Valve engines, Piston Port engines I have never had a negative running effect due to a leaking seal, but my Puch is very sick and I have done everything but change the crank seals, so this engine type may be affected by a leaking seal. I have not changed the Seal on my Puch it's a big job for any engine usualy requiring dismantaling the entire engine, so if you pull the engine apart might as well do an entire engine rebuild. I do not recomend dismantling the bottom end of an engine unless you know what you are doing or can practice on a junk engine, the parts are very fragile usualy made of aluminium, damage iis certain to inexperience. None the less I am shure there are a few bikes that have some problem that the owner cant figure out after doing everything, a Crank Seal leak is what to look for when all options have been exausted. It can be easly identified by oil or transmition fluid leaking out and soiling the bottom of the engine or clutch.