Anyway, back to the build. I picked up the bead blasted head and cylinder block and was pretty impressed at how clean they got them, there were still a few specs of black on the head, but nothing horrible, so I dumped them in the ultrasonic cleaner to flush away all the blasting grit.
Z1 Top end build 16 Aug 2020 by
Terry Prendergast, on Flickr
I then used my dremel to clean any obvious bits off the head, while I repaired some busted fins on the cylinder block with JB weld's Steelfix epoxy, and dremeled/filed the new fins back into shape. I had to paint the cylinder block because the JB weld is black, so would have stood out like dogs balls. I was happy with the finished product though, as the high temp paint I used almost looks like bare blasted aluminium anyway. I gave the cylinders a light hone, not so much to repair any internal damage, but just to remove the light rusting caused from the ultrasonicleaner, and the clean water flush afterwards, before I dried the block in the industrial oven at 100 deg C for a couple of hours.
Z1 Top end build 16 Aug 2020 1 by
Terry Prendergast, on Flickr
Z1 Top end build 16 Aug 2020 2 by
Terry Prendergast, on Flickr
I think I mentioned in a previous post that the OD of the KZ1000 1100cc sleeves are 2mm larger than the Z1 sleeves, and I was concerned that they may not fit in the holes in the Z1 crankcase, but as luck would have it, they are still 1mm smaller than the holes. Thank God for that. I installed a new base gasket and cam chain idler wheel, and using my fancy home made piston blocks slid the well oiled sleeves over the Moriwaki pistons. My heart was in my mouth after my last effort where I broke two rings on the 1428 engine, but this time it was easy, especially because the Moriwaki pistons only have one compression ring, unlike any other 4 stroke engine I've dealt with. All pistons went in with no issues at all, and are a nice tight fit. I made sure they each went into their original bores, so I'm pretty confidant there'll be no compression issues.
Z1 Top end build 16 Aug 2020 3 by
Terry Prendergast, on Flickr
Well with new two piece head gaskets in place, there was nothing for it but to install the head, woohoo! New copper washers installed along with the fancy OEM head nuts, and I torqued it down from an initial 10 foot pounds, to the recommended 30 foot pounds in 5 foot pound increments. Nothing went snap, everything looked good, so I celebrated by cracking a Ginger Joe.
Of course, when everything seems to be going right, something will always fcuk you over, that's Murphy's Law. I've become rather adept at setting the cam timing on these engines with all the work I've done on the 1428 engine, so it didn't take long to set the timing and bolt everything down. I'd already cranked the engine a few times before I set the timing and the engine turned over fine, so I was horrified when I tried to turn the engine over with the cam timing set, that the engine wouldn't budge? WTF? Was a valve hard up against a piston? I wouldn't have thought so, as the cams and the pistons came out of the dragbike engine, so as the Z1's combustion chambers are more cavernous, I couldn't understand why?
I loosened off the cams, removed the chain, cranked the engine over again, and it was fine? Weird. OK, so leaving the chain off, I reinstalled the exhaust cam, tightened it down, and tried to turn it using a 10mm ring spanner on one of the cam bolts, and couldn't budge it? Bugger! Now I think these cams are stock GPZ1100 cams which have a fair bit more lift than the stock Z1 cams that I don't have anyway, but regardless, they weren't binding in the other two heads I'd tried them in, so I wondered if maybe the Z1 cradles were slightly smaller? I had a lightbulb moment this morning and bolted two top cradles together around the bearing surface on the exhaust cam, and yep, I couldn't rotate it.
I took the cam into the garage, set it up in my lathe with one end in the chuck and the other end on a live centre, and spun it up while polishing the bearing surfaces with some fine emery cloth, followed by some wet and dry sandpaper with a little WD40. I then polished the bearing shells and the holders, bolted everything back together again, and all was good. No binding, and no slop either. Sweet. All going well I'll do the same on all four cam bearings and have the cams in and timed tonight. I must say, it is looking good.........
Z1 Top end build 16 Aug 2020 5 by
Terry Prendergast, on Flickr
