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Vertical Engine Case Leak   Fact or Fiction

I noticed in a report by John Cuff about a 650 Yammie. He happened to quip that vertically joined engine cases leak. Well I’m afraid I’ll have to rebut that statement ( in Jest by John I’m sure) as I have been involved with British motorcycles ,in particular the 50’s through 70’s era and only once have I seen that to be the case. Early on I had closed up a T140 case with some red Loctite gasket sealer and did not replace said engine back in the frame immediately and thereby squeezing up the bottom of the case with the main lower bolt. It did indeed leak. This I might add is not a practice that is required. That particular Loctite sealer seemed to wick off into a thin sheet. So a complete strip ensued and also a search for a better sealer. This is the  only one I have seen leak like this and I have been doing singles, twins and triples for 40 yrs at more than 10 a yr. I have done 5 this yr so far and I’m retired. Now days I use Permatex  Grey, only one shade, as it is better than ugly red, blue or black seams from other colour sealers. But, I have also found that these old Pommie bikes leak from every other conceivable place possible if given the chance , in particular , seemingly purposely designed to leak, tin sump plates. Therefore what people mostly think is a case leak is a leak higher up the engine then dripping from the lowest point which happens to be the alleged, Case Joint.

In jest,  Brian

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