Kz 400 engine , alternator cover blows !!! ??

Hola Everyone ,

this is very strange , i restored a kz 400 from 1978 , all engine resotored , new pistons , engine sounds perfect , rode with it for 50 kilometers , and later alternator cover cracks and oil comes out .... strange , i gt a new cover from Ebay , replace it , and it does it again !! ..

could you please help me , what do you think its creating this problem ..

thanks

The generator's coil field is attached inside that cover. I wonder if the rotor is off center (bent crankshaft?) and is striking the coil field causing the cover to fracture. Also, those are not the correct bolts holding that coil field to the cover (should be Allen bolts) so I wonder if the coil field became a bit lose and cause the rotor to hit it. I would remove the cover and use a dial gauge to see if the rotor and crank are running true. If they are, I would be sure to attach the field coil to the next cover using the correct 6 x 18 Allen bolts. While you have the cover off look to see if there are any telltale signs of the rotor contacting the field coil.

Also, it looks like an excessive amount of oil inside that generator cover. I'm thinking the crankshaft seal may be damaged, and that could happen if the crankshaft is bent. Perhaps someone with a KZ400 can tell if that oil is normal, but it doesn't look right to me. Ed

Hello Ed , it makes total sense what you say , we took the cover off and what we found is a perfect circular marc on the bottom of the cover ( where it exploded ) .. the marc is circular , so i would say this rules the offset or bent crankshaft no ? what im afraid is that the nut / bolt that holds it is to big and for some reason it "forced" its way out , braking the cover ?? , please see atahced pictures ..
maybe 2 many washers on the bolt ? would it help if we trimm the head so it does not touch the cover ?

any ideas ?








now , the oil , there should be a normal amount of oil in there correct ? , or it should be dry ? i cant remember ?

thanks for the quick feedback .

Someone with a KZ400 will need to chime in on the oil issue; I don't know if it should be wet or dry. Ed

1) there is oil in there
2) what does the end of your crank look like?
there should be a bolt holding your other component to the crank, maybe the bolt backed out and took out the cover.