1975 Kawasaki KZ400 Scrambler Build

#1
Hey guys, we've been working on this KZ for a few months now and figured a build thread might be in order. This bike was purchased off Craigslist a few years ago for $350 in sad shape. It didn’t run and everything about it was ugly, but there was potential. Since this was back in the days before Overland Empire really started, the first build of this bike was as a café racer. We got the engine running properly with a set of brand new Mikuni VM32 carbs and some tuning, pulled off any extra accessory and piece of body work that wasn’t deemed necessary, made a custom seat and shod it with some vintage Firestone Deluxe Champion tires. And it was fine and good, but it was never quite finished. Really the only true missing piece was the taillight, but it just never felt done. Then came Overland Empire.

As the brand got rolling and we started documenting our adventures, this bike was always sitting in the corner of the garage, haunting us with it’s potential. Then right after the dawn of the year, it was time. We knew this bike had to become a scrambler and be geared up for some adventures of it’s own.

The original bike as found:
IMG_0302.jpg

As it stood before the Scrambler project:
Cafe_1200.jpg

So now we'll be playing catch up on this thread to bring you up to it's current status. More coming very shortly.
 
#2
The first order of business was to create some design sketches. Knobbies, high pipes, an upswept hoop at the back, a new seat, tracker bars. It didn’t take long to realize what was needed. A quick photoshop comp helped bring it to life as well. So then it was time to tear apart the bike. Every single piece came off. Down to a naked frame. It should be noted that this is being done on a pretty tight budget. There’s no room in the budget for Ohlins shocks, custom CNC machining, etc. Not even money for new rims. All existing parts will be reused, cleaned and/or powder coated of course, and only the necessary things will be purchased. This time around we’re going to build it twice—once as a working, running, perfected mock up, then tear down, powder coat and paint, and then build it all up again as a final bike. This would allow us to weld anything necessary once it was built or make any mods before paint and powder coat.

The photoshop comp:
kz400 comp.jpg

First of those necessary purchases were tires. And since new wheels were out of the question, we had to find tires to fit the stock Takasago 18” rims. Finding a modern 18” front tire is no easy task either, especially in a street legal knobby. Finally we settled on a Pirelli MT-43. 4.00x18 front and rear. It’s got just enough beef to hold in the dirt but plenty of contact area for the road. So once those were ordered we went to work on the wheels. The old semi-rusted spokes came off and the hubs were cleaned. We didn’t want the super-shiny mirror polish on these—this bike is going to be ridden, not put in a shop somewhere as a show pony. But it took many late nights and a lot of elbow grease (and Never-Dull and Mother’s Aluminum Polish) to get these things clean. Then a set of Buchanan’s stainless spokes were ordered to lace up to the freshly powder coated black stock rims. Since lacing and truing a rim isn’t exactly our area of expertise, we turned to a local expert who got them all perfect for only $50 apiece. Wheels and tires, done.

Pics of those coming soon.
 

Chris Cordes

Expedition Leader
Staff member
#6
Does your frame lay flat like that in the rear or are you chopping? You can see mine has a good deal of arc in the back. It's a 440 though
 
#8
Does your frame lay flat like that in the rear or are you chopping? You can see mine has a good deal of arc in the back. It's a 440 though
The frame is straight in the back. We're welding on a loop (actually already welded it, just trying to get caught up on the thread) that will have a slight upsweep for more tire clearance in the rear. Should have pics of that up soon. But the flat section behind the tank is stock and will stay like that.
 
#13
Sorry we don't have great pictures of all the steps up until current day. Just trying to catch up on the thread!

So next was the matter of the upswept tail hoop. When we built this bike the first time (café racer) we had a regular hoop fabricated with no upsweep. After calling that same shop a dozen times over two weeks with no answer, we had to find a different solution. We ordered the small CC tail hoop from Tampa’s Dime City Cycles, where we purchase most of our two-wheel goodies. That tail hoop measures 7” on center, and we needed about 7-3/8”. After about an hour of unsuccessful attempts with a bench vice and long length of pipe, we decided to take another approach. We welded the one side on and then used a regular scissor jack and a tie down strap to align the other side perfectly with the frame. Tail hoop, consider yourself welded.

The hoop before welding:
IMG_0544.JPG

The engine had been painted in the prior build as well, and instead of stripping or bead blasting it was decided to just paint it again, this time in a more true shade of aluminum. Maybe not the most ideal, but it works. Then many more hours and a few beers were spent polishing the side covers. Again, not to a mirror finish, but they look good and clean and 100x better than they ever did. This old engine had a pair of cracked rubber intake boots on them that needed replacing badly, and it took plenty of dead-end Google searches and a couple months of checking eBay before a new pair turned up. Once those were in we had to remove the old stripped screws. Screw extractors didn’t do the trick, but a nice pair of big Vise grip pliers did. And maybe a few more beers. Made the upgrade to stainless steel button head hex bolts and we were back in business. Any screw or bolt on that engine that could be upgraded to stainless steel has been. With the engine back in shape it was mounted to the frame.

The in-progress engine with the old rubber boots:
IMG_0517.jpg
 
#14
We’re still kicking around what the correct foot pegs will be for this bike. Thought about some MX style pegs, but it just feels a little unauthentic. Maybe it’ll be the way to go, but for now we tried something a little different. We had a pair of Cult Vans BMX grips laying around from another project, so after some work with an x-acto knife to shorten the grips and the bench grinder to shape the end of the foot peg, these were a perfect fit. We’ll see how they stand up to some rides, but they won’t be hard to replace. All that’s left now is to drill out the odd shape on the end to be able to insert some bar ends to finish off the look and keep crud out of the hole.

OE scrambler Vans footpegs.jpg
 
#15
When it came time for the rear shocks we needed something with a bit more clearance. We picked up some 14.5” shocks from Dime City and went about fitting those. The stock passenger footpeg mounts stick back into the frame and cause the swingarm to not travel as long as we need it to, so those were promptly chopped off. We’re still figuring out if we want passenger footpegs or not, but probably so since the supports can’t be cut off—the rear brake and spring are mounted to the right side support. So we’ll probably figure out a solution for those soon too. With the mounts cut off the swingarm travels freely to allow those 14.5” shocks to be mounted. And that gives a nice amount of clearance between that beefy Pirelli tire and the frame.

At this point we could basically put everything together and mock it up. So the engine goes in the frame, the tires and wheels get mounted, footpegs go back on, headlight, handlebars, carbs, just enough to start seeing the shape come together. And if we can say so ourselves, it’s looking pretty good.

Motorcycle_June-2.jpg

As much as we loved the stock headlight (seen in that second pic in post #1 with the red shirt) it just wasn’t bright enough and was so out of date. So we decided to upgrade to a new model with the same overall feel. A 7” unit from Dime City now lights our way up front. That’s a stock gas tank, and will get painted when this is all said and done. Still a lot of things to do and plenty of decisions to be made, but it’s coming along.
 
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