This is part three of the ongoing saga of working on my old Z650 (my expectation of a couple of weeks just to get the bike back on the road has turned into a restoration lasting well over a year !).
I had decided to work on seeing if I could get the original engine up and running as a spare that could be dropped into the frame if the one currently in there broke or was no good.
In the end, I have come to the conclusion that while it could be done, there are a lot of significant issues that I'm not sure I have the equipment or knowledge to solve.
But I've got a second spare engine, which is more complete and has less known problems, although it has been under the porch standing for years and will need more cleaning than engine 1. I took it out of the bike years ago when one of the screw flanges for the manifold input broke off. Fixing that is a job which would require the head to be stripped down, alloy welded and the screw hole then re-drilled and tapped. The welding and re-drilling are beyond what I've got the tools to deal with !
Hoping to make it easier to work on this engine, I bought an engine stand - I wrote a post about it - My Christmas Present To Myself
Having put the stand together, I realised it's really designed to work with an engine winch, which I don't have. So what I did was lie it down on it's side and loosely bolt the engine into it...
All images in this post are my own photos
Getting it upright was a job for lots of pure brute force. My wife helped (she's strong !) and it was definitely a two person job.
As you can see, the thing is filthy ! Although it has been under the porch, which has meant it has (mostly) stayed dry, it has picked up a huge amount of wind-blown debris. It's also clearly a habitat for a large number of spiders, and I can't rule out the possibility of mice nesting in the combustion chambers.
An advantage of the engine stand is that it's possible to tilt the engine. It was only once I did that that I discovered it is so heavy it jammed the locking pin, so it will be a two person job to tilt it back again. I think the engine is actually so heavy that it's right at the limit of what the stand can handle.
So how does this engine compare to the first one ?
- Overall it is far more complete. On engine 1, the cams, cam caps and buckets were removed (although I still have them).
- The alloy on engine 2 is a lot more "furry" than on engine 1.
- Engine 1 turns over freely. I haven't tried turning engine 2 over yet.
- The bottom end is in far, far better condition. On engine 1, the output shaft thread is stripped (needing a replacement shaft and crankcase split to change it), the locating pin on the right hand end of the crankshaft is snapped (no idea how to fix that yet, but it'll probably mean drilling it out), and the alternator rotor is badly corroded. None of those are problems on engine 2.
- The top end on engine 1 is in better shape, the top end on engine 2 needs (at the very least) a full strip down, welding and rebuild. But neither is very good; I have another spare top end, so I'll probably compare all three and work on whichever one is best.
- The barrels on both engines have some fin damage, although engine 1 is slightly worse. I also have a spare set of barrels and pistons, although they are buried in the shed so not sure what condition they are in ! The reality is that the fin damage is minor and mostly cosmetic, and the decision on which one is best will be more about measuring the pistons and barrels to see which are closest to manufacturing tolerances. I accept I may well need to hone the bores and replace the piston rings.
After taking these photos, I gave the engine a good brush down with a stiff but non-abrasive brush 9actually, it's a plastic dishwashing brush), just to get most of the loose debris off. Then I had to push it back under the porch and cover it because the incessant rain started up again. I know we need the rain to keep the garden green, but freezing cold heavy rain nearly every day for a month is getting a bit much !
When it stops raining, I'll carry on with the project and post an update.....