Crankcase plugs

Hi, 1979 KZ650 B3, can anyone tell me what the purpose of the 2 crankcase plugs are for. There is also 1 in the sump housing. One of the crankcase plugs in my bike has a stripped thread in the case and on the plug. If there is no real purpose to these plugs instead of getting it heli-coiled and new plug I might just tap the thread and glue it back into place. 

1. Under ignition cover is the oil pressure switch port.

2. In you pic, oil pressure service test port for the pressure gauge and the factory line bored oil gallery (main crank bearings).

3. Oil pan drain plug.

 

Vietvet wrote:

Hi, 1979 KZ650 B3, can anyone tell me what the purpose of the 2 crankcase plugs are for. There is also 1 in the sump housing. One of the crankcase plugs in my bike has a stripped thread in the case and on the plug. If there is no real purpose to these plugs instead of getting it heli-coiled and new plug I might just tap the thread and glue it back into place.


 

Look in the FSM there should be a oil flow diagram/picture to explain the oil flow.



The plugs are there as a part of manufacturing the casting, they line drill that hole because it is the main oil feed that runs oil from the pump to the crank, then up to the head. This is also the same case for the oil pan, the oil pan has a main feed that joins at the bottom of the case where there is that flat O ring. Just follow the arrows in the diagram and the numbered chart below it.

They drill from both sides so it makes sense they require threads and plugs that are serviceable. It is also good to have those so you can run a bottle brush thru to clean out oil gunk when cleaning the cases. The threads can be used to attach one side of a oil cooler, the other side going back to the oil pan.

I would not "glue" anything back in as its under quite a bit of pressure especially at start up and once hot it will probably leak all over the place. That is not a good place to have a oil leak as it would get on your pants while riding.

Try to look into a more solid repair especially since you put a lot of effort into the bike so far.

PS - You can still buy those plugs new from Kawasaki.