As I mentioned before I bought two bikes to start with. So I got two XS750 engines to choose from. One of them wasn’t running for more then a decade and the other one was pretty much at the end of its life. Anyway the second one was a 1978 build. Which means it has a around ten horse power more. Biggest different is the cylinder head and the carbs. And this engine was running.
So I started to disassemble this engine first. To my surprise the head was not in such a bad condition. At least all the valves are tight. I poured some petrol in the in- and outtakes and nothing went through the valves. That’s a good start. The cylinders didn’t look so bad as well. A bit of the cross grinding was still visible. So I decided to stick at least with the head, the cylinders and the pistons.
The rest of the engine wasn’t that good. When I opened the oilpan I found a lonely washer inside. Should not be there.
Later I found a very massive washer and a ripped off thread in the left side, where the clutch is. And from the outside the engine was quite oily. So it looks like there are few more problems with this engine. At this point I stopped with the disassembly. Not worth the effort.
Last week I took a closer look at the other engine. In the beginning it wasn’t turning. With some help of a bit of WD40 and some time I was able to turn it again. I took off the head and the cylinder. It looked like the head was never off. Pistons of the original size, everything looks not too bad according to the kilometers this engine was running.
Interesting detail is the sand at the threads of the cylinder/cylinder head. Wounder how it found it’s way down there. And yes, I cleaned the engine before.
I didn’t look like some of the sand found it’s way inside the engine. With some help of the hover the sand was gone. Next I checked the clutch and the primary drive. The clutch was fine – every piece was at least 3mm thick. The primary drive chain looked a bit long to me. So I replaced it with the one of the other engine.
Now I’m going to paint the sides covers of the crankcase, the cylinder and the cylinder head. The crankcase itself doesn’t look so bad. And then finally the engine can go back in it’s frame, where it has already spent the last 39 years.