1979 KZ400 B Restoration/Recommission

Next I was able to install new needle bearings in the upper crankcase for the selector drum and fit that along with the forks



Before carefully dropping the gears into place as well



This is my first time doing this so it's all been a bit of a learning experience, one thing I nearly missed is that the kickstarter shaft and pawl had to go together in a certain orientation. I hadn't noticed this when I cleaned and re-assembled them so that got re-aligned and fitted, very glad I caught it now and not after the crankcases had been assembled!



Most recent job I've done is check the piston ring gaps which were all fine, and installed the rings to the pistons



I had a minor debacle with the oilway plugs for the crankshaft so I have some new replacements for those coming, but that should be the last thing stopping me from installing the crank and getting the bottom end all assembled

Great documentation well done !!

Hi Adam,

Well done on this recommission ! Since your engine is still apart, would you mind telling me the diameter of the crankcase holes where the cylinder sleeves are supposed to fit in ? I need this measurement in order to know if I can get a kz440 cylinder block on a kz400 later model engine. That would be super helpful. 

Cheers,

Thanks

Michel, just took a rough measurement, I get around 75mm for the diameter, hope that helps?

Thank you Adam. I had somebody else give me the diameter (76mm) so I hope yours is on 75+ because I went ahead and bought a 440 cylinder block
It's doneanyways so I'll see when it's time to install it...

I was waiting on some parts in my last post but they eventually turned up and I could get on with re-assembling the engine. First up was the crank, minor debacle with the oilway plugs now resolved, and conrods installed



I then installed the crank into the upper crankcase but made an error which I thankfully later caught before I joined the crankcases. I did get stuck waiting for parts here again as I was missing an O ring for the oil feed into the balancer assembly



In the meantime I did a little renovation work on the valve adjustment and chain tensioner caps, these were all fairly corroded. Some 240 grit paper got most of that off, refined with a bit of 480 grit then finished off with some polish



So I'd made a couple of mistakes with the engine balancer assembly. First thing was I'd put the chain on the "wrong" way round so the bright links weren't on the same side as the little hole in the sprockets. Not the end of the world but made it a bit trickier to time them up.

I did time each of the weights to each other correctly, and I had the crankshaft in the correct orientation with the flywheel webs up, but I'd missed that the weights needed to be timed to the crank which is a really obvious thing to miss in hindsight! With my error spotted, I took the balancer assembly back off, re-mounted the chain so the bright links were on the right side to make things easier, then noted the small marks on the balancer assembly mounting block that are supposed to be matched with the bright links (the manual wasn't very clear on this).



Got it all reinstalled, torqued up, happy days. In the meantime the missing O ring arrived, I cleaned up the mounting faces, made sure the bearings were oiled, put a thin smear of permatex grey on the mating surface and it looks something like an engine again

Things have gone together pretty quickly since getting the crankcases back together, gear change shaft went in and engaged with the shift drum. I also took a few attempts at fitting the kickstart spring, in the end I had to go and buy a better pair of needlenose pliers to get it in and stay in but it works nicely now



On the other side, I got the alternator rotor on and mocked up the starter and chain at the same time. The starter chain was in a bit of a bad way when I got the bike but given a thorough cleanup it looks like it's still got life in it



Pistons went on the rods nicely, and thankfully didn't lose a circlip into the crankcase haha

[img]https://img.retro-rides.org/i/v/adam73bgt/9ae48ecaee89.jpg[/.img] The cylinder barrels were a bit more tricky, I ended up using a couple of cable ties to help as piston ring compressors but got there in the end. I also realised I forot to fit the rear cam chain guide but was able to lift the barrels up again and get the guide in with its location pins [img]https://img.retro-rides.org/i/v/adam73bgt/b94f261ea1f6.jpg[/img]

With my girlfriend helping feed the timing chain through, it was a pretty simple job to pop the head on top as well and torqued it down, I'm pretty happy with how it's shaping up