Topic: 1975 Honda CB400F Engine Case Crack

[cgarbe]

So I am having my CB400F restored and updated and after getting it to start (on the second kick) it started leaking oil. Come to find out there is a gob of JB Weld beneath the drain plug on the lower engine case. After some investigating we found a crack (where the JB Weld was located) that spans into the drain plug. Not sure what to do…replace the engine case (and have the engine rebuilt) or search for a new motor. Thoughts?

[MoMo]

If it is near the drain plug that is part of the oil pan cover and can be removed and repaired or replaced. Are you sure it is the crankcase?  Seems more like it would be the pan...Larry

[faux fiddy]

If it is near the drain plug that is part of the oil pan cover and can be removed and repaired or replaced. Are you sure it is the crankcase?  Seems more like it would be the pan...Larry

+1

Is it 11 bolts?  You can reuse the gasket if it's not shredded, yamabond helps. You can at least clean it all and inspect the pan.

[Rigid]

If it is the case, clean it up real well and either JB weld it again or get it carefully TIG welded in the frame.