Upgrading a KZ400 engine with 440 cylinders and oversize pistons

There was no need to cut exhaust valve reliefs, there is plenty of it. As for advancing the cam. You will need a slotted sprocket or the quick and cheap way of advancing the cam 1 tooth. But remember the KZ400/440 rotates backwards. By advancing the cam exhaust valve clearance increases. 

I cut the valve reliefs because the 400 has some fairly large ones, and the original 440 pistons had nice divots in them where they hit the exhaust valves. Maybe that was from a loose timing chain or some other failure but I'd rather have clearance and not need it then find out the hard way. It's good there is plenty of clearance but the milled head and no base gasket brought the valves ~1mm closer to the pistons. If the reliefs aren't necessary that's great. If the valves need a little more clearance then it's there. Looking at it during mock-up and after final assembly showed good clearance either way.
I decided to set the cam timing to factory for now. The cam gear from a 650 has a few different mounting points and a couple of them would give me the slight advance that I want. I was going to use one of those but it uses a different timing chain. So in the future I'll either find/fabricate a slotted cam gear like Nebr_Rex said or find OEM parts that will work. 
New Vesrah heavy duty clutch springs should be arriving today. The engine from the '74 has a "new" clutch pack so I'll probably use that with the new springs on this. Once I install that and put the covers back on I can begin swapping this engine into the 74. 
I found a dynamo cover from a 78 KZ400 that has the all caps logo and matches the later bolt pattern. Should look nice after it's cleaned up. I like the all caps KAWASAKI logo a lot more than the later one and it looks like this was 78 only. 
 

100% agree with you on the logo. Being a Kawasaki fan can be hard sometimes because the branding is just so Monster energy neon green. They’ve made so many great bikes beyond the Ninja series (no shade on the Ninjas, they’re great too!), and the heritage and pedigree of their bikes is historically significant. I wish they would recognize and embrace all of those variances more, and give us “old school” Kawasaki fans a little more fanfare. 

Stereordinary wrote:

100% agree with you on the logo. Being a Kawasaki fan can be hard sometimes because the branding is just so Monster energy neon green. They’ve made so many great bikes beyond the Ninja series (no shade on the Ninjas, they’re great too!), and the heritage and pedigree of their bikes is historically significant. I wish they would recognize and embrace all of those variances more, and give us “old school” Kawasaki fans a little more fanfare. 

I'm with you. Can't beat the style of classic Japanese bikes and Kawasaki hit it just right. The first motorcycle I rode was a Ninja and I do like those a lot too, but the look and feel of UJM bikes is something else entirely. 
The engine is mostly assembled I'm just waiting on a few small things. Trying to do all of my homework so it goes smoothly but I'm excited to get it on the trailer, rent a shop space for a day, and swap it in! 
I haven't fully figured out the charging system - the original is a 3 phase and the 79 that's going in is single phase. Probably just a regulator/rectifier swap? I might have to pick some of those parts off my "parts bike" even though I'd rather not strip it down too much. I want to get that one back into riding condition when this project is done.

Time to get the bike ready so I pulled the engine and wiring harness. 
 

Cleaning up the wiring. It isn't done but it's getting there. Good condition overall so it doesn't need much. Still need to finish the charging system and I'm adding a relay for the ignition coil. Then it's getting a test fit before I wrap it in some good quality black electrical tape. I want to hide the electrical system so it's as clean as possible but I'm not spending 20 hours building one from scratch.
 

Engine is bolted into the frame and I swapped the swingarm for the LTD one. Next is bolting everything on and figure out the carb mounting with the Murrays kit that came with my 79 LTD. The frame is in the way of the carburetor but it looks like it will clear with a spacer. 
The 79 harness is better than the 74 from the factory. It's in great shape too so instead of taking it apart for the charging circuit I'll just use the whole assembly. 
 

The LTD swingarm is 2" longer. Easy swap the only difference was the wheel spacer at the chainring.
 
 

Time for another thread update! Wiring is mostly finished. I mounted the starter relay, regulator/rectifier, flasher, fuse box etc all onto the battery tray. I'll fabricate some brackets and make some adjustments later on but for now this is great. Yes I am doing this in my apartment.
 

Gauges and headlight/front turn signals are the only things left to plug in. I want an electronic tachometer so I've been searching for an aftermarket one that I might be able to swap the internals into a factory housing. If anybody has some ideas for that I would love to hear it.
 

Since I swapped the swingarm from my 79 LTD onto this I decided to put the wheels on it too. I think it looks awesome. They have fresh tires that I bought last July plus the bearings had been gone through. The original spoked wheels from the 74 need work and new tires before I'd run them.
 
The LTD swingarm bolted right up. I trimmed the bottom of the plastic inner fender since it had some interference. I plan to add a piece of thick rubber/mudflap material to extend that and keep debris out.
 

I had to get a little clever with the brakes. The rear drum mechanism hit the muffler so I mounted the actuating arm facing up. The design of the brake means it will work in either direction.
 

The factory 74 fork is in good shape and had the seals and bearings replaced so there is no reason to change it. To mount the LTD wheel I used the 74 thru-bolt. Everything else from the 79 wheel worked but the caliper needed a spacer. 6mm worth of washers between the caliper and fork gave it enough clearance until I figure out a good caliper upgrade and design an adapter. Anybody have ideas/experience upgrading front brakes to something more modern?
 

Also my 79 had the Murray's 2 into 1 manifold with Mikuni VM34. I had it dialed in just right and the maintenance is so much easier with one carb versus two so I'm keeping it.
The only problem is the manifold puts the carburetor right into the frame on the 74. There is enough space to figure something out so I'm currently searching for parts to do that. 
 

That's it for now. I'm really happy with how it's been going. The bike is starting to look like exactly what I want and that's why I started this project in the first place.

Plug for the the tachometer cable hole. Used a M14x1.5 tap and a magnetic oil drain plug with sealant on the threads and an o-ring.