GS400 Upper Crankcase replacement

[Guest]

Hello fellow enthusiasts. I'm new in the forum and would appreciate any advice on how to replace the upper crankcase of a GS400 without having to dismantle complete engine, invert the crankcase, separate lower case and disassemble all components inside as described in the manual. In short, is it possible to just leave the engine in the frame and dismantle the head, cylinder, cylinder studs, upper case bolts and then lift up the upper case and replace a new upper case?

Thanks in advance for your input.

[Nessism]

The case halves are line-bored together as a set and you should not (normally) try to mix and match those parts together. And even if you had to try to break up a set, the engine has to come out of the frame and the entire engine disassembled before the upper half could be replaced.

[ptah52]

That's what I was afraid to hear. But many thanks, Nessism, for your definitive advice. I was just hoping to find a short cut to replace the upper case.

[Chuck78]

You must replace both case halves as a matched set. Same goes for cylinder head bearing caps and cylinder heads. When I see clueless eBay sellers selling one half of a crankcase, or a cylinder head without the bearing caps, or the bearing caps separately, they get an obligatory message from me telling them the error of their ways, abd that they are setting up the new buyer of these parts for a definite catastrophic engine failure!