With a new homemade spindle I could finally fit the rear end, though the bearing kit I bought for the swingarm didn't include any spacers, so need to find or buy whatever is required. Life would be easier if I could lift the bike off the ground, and onto a bike lift, but nearly put my back out trying on my own, so it can stay on its sump for now.

Made a start on the foot controls, chain drilled the mounts from 10mm alloy plate, test fit on the frame, showed I'd made another mistake. The brackets put the foot pegs 40mm lower than the standard position, so the gearchange side will need to be remade, while the brake side can be saved I think.

With the 43mm R6 forks off being rebuilt, I dug out an old pair of ZRX stanchions to try out the head light mounts. We weren't sure how big to make them, so they turned out to be way too long. So need to cut them back to bring the headlight back much closer to the headstock.

Dales rear swing arm is off a ZRX1100, I know I have the same basic setup.   However, there is a company call MotoGPWorks that sells a exact S1 swingarm replica for about $1300.00 bucks.  I found that the ZRX1100 setup is plenty strong enough, and raises the rear about an inch, thus slightly reducing the rake angle. I have about 3500 miles on my zrx1100 swingarm and I can definitively say it makes a huge difference in handling.  I also, at the same time, increased the swingarm pivot bolt to a 20mm using a ZRX rear axle, it fits perfectly.  I believe the last iteration of the twin shocker GPZ/J models frames are pretty dang good handling.  Their biggest issue was the spindly rear swing arm (frame wise) and slop in the bearing to pivot bolt connection.  Goes without saying the forks and rear shocks were lethal in stock form.  I swapped out the rears for a set of zrx1100 KYB's, which are light years ahead of the stockers, the forks were re-worked with  RaceTek springs and gold valve cartridge emulators.  I re-worked the emulators to get a tighter seal and a progressive type high speed valve spring.  I fine tuned the fork oil as well...this made a huge difference.  These old forks have way too large oil passage holes, they require thick heavy oil to actually dampen.  With emulators installed you can actually have high speed and low speed dampening.  

JM2C
577Nitro

I’ve made a lot of progress.  Let’s start with the brakes.

I didn’t plan to rebuild the entire brake system, but it sort of happened anyway.  

I had the rear wheel and swingarm off, so I had the idea that I would remove the rear caliper just drain to drain all the old fluid out, then put it back on and bleed it.  But when I pulled it off I found two things. First, one of the two bolts that holds the caliper halves together was about half-way out.  OOPS.



Second, it was clear the seals were leaking and the pads backing plates were rusty.  So it all came apart.



Based on recommendations here, I got a rebuild kit from Brakecrafers.  I bought the later style 79-80 pistons with the insulating disk.  I figured why not.  I had two issues with the kit.  It was missing the correct seal for the passage between the two halves, and the dust seals wouldn’t stay in place.  It seemed like they were too small, and would just pop off of the lip on the body no matter what I did.  I spoke with Brakecrafers and they were very eager to help sort it out.  Absolutely an “A+” for customer service.
I had already ordered OE parts to replace the kit parts before I spoke with them, but he assured me that the dust seals in the Brakecrafers kit were identical to the current OE parts.  This appears to be correct.  The OE part I later received looked identical.  I ended up cleaning and reusing the existing dust seal, which were fine and did not pop off.





And for good measure, I also rebuilt the rear master.



I used an aftermarket kit from Z1parts.net instead of the OE parts.  The piston wasn’t quite as nicely made as the OE part, but it looks like it will work fine.  

z1parts.net/kawasaki-rear-brake-master-c...r-repair-kit-kz1000/



 

Thanks for the link and tip on valve clearances. I own a couple of old Yamahas that require the occasion carb clean and they are really sensitive about cleanliness.  These carbs were in relatively good shape besides some varnish.  We checked/ measured all parts from the kits vs the installed parts.  These carbs don't appear to have been disassembled before.  We have a valve cover gasket on order.  I think it's better to have one on hand before disassembly.  Waiting on a lot of parts on order, there's quite a bit to do before it's rideable, front and rear brakes- I don't trust 44 year old brake shoe lining adhesive,  rebuild master and caliper, brake hoses, we need air box boots, rear brake switch, turn signal flasher, chain and sprockets, fork seals/ clean and rebuild,  steering head bearing clean and grease,  swing arm bearings clean and grease.  It's in amazing condition overall but there's safety items that I can't help but replace and or service before going around the block even.  I'll post some pics once I'm allowed to.   Thanks again!  

Well my 1975 build date A4 900 is done. I have put about 60 miles on it so far and it seems to be running in well.

Everything is original, or like original upgrade. I hade the factory gauges rebuilt and used the shorter turn signal stalks and mirror mounts. I have all new factory decals.
I installed the Z900 dual disc upgrade.

The changes to the suspension really made a the difference. I changed to caged bearings in the steering head and rear swing arm. The front forks got new tubes
and Racetech bypass emulators, the rear shocks are period looking rebound adjustable ICON shocks. the bike is very stable and predictable in corners.

The engine is completely brand new, only upgrades are better cam chain parts, 1st overbore, better valves and seats, rebuilt clutch basket and crank. I'm running it in on
brake-in oil.

Only problem I have had is with the fuel pipcock. When warn it only wants to run right on reserve. Im gonna go non-original and just run a Pingle valve.

Thanks for all the help everyone has given me. All total, I spent about 14k, including the cost of the bike. What do you think a 98 point A4 is worth?

Just back from seeing  the bike; I didn't buy it. It wasn't expensive for what it was, but I really wanted a more original bike - a lot of bits had been swapped out. Some of the original parts came with it, but weren't in a very good condition. Putting it back to good original condition would probably have soaked up more than the low purchase price would have given me. The motor was fine when warm, it just needed keeping in life with the choke when cold. The owner thought this was due to it having K&N intake filters.

It was indeed the starter clutch that had failed, but the handlebar starter button had also failed. 

I looked at the Zephyr swing arm, and then at the original. I must say, the Zephyr one looked really good, it seems it was a straightforward swap, just a spacer was needed for the swing arm pivot bearings. It had eccentric adjusters and generally looked a lot more substantial than the stock one. Maybe something for others to consider.

It was lovely to get back on a Z650 again after all those years, it rode and sounded as nicely as I remembered. Instant smile on the face stuff.

So I'm looking again...

Ian

I have a ‘90 Zephyr 550. It’s a great bike and the whole Zephyr series share many attributes, which I would say represent what happens when Kawasaki doesn’t “cheap out” on components. Dual disc floating rotors, aluminum box section swingarm with eccentric chain tensioners, tapered roller steering head bearings, and 4 into 1 exhaust all stock. 

From what I’ve gathered, they didn’t have much success because the timing just wasn’t right. They were air-cooled standards tuned for mid-range power at the time that some of the classic liquid-cooled super bikes were coming out. 

My shocks turned up today, I have some clevis fittings to suit the GS swingarm, will test fit tomorrow.
These shocks are Chinese, They are an Ohlins copy and are very well made, We have already pulled one set of these apart to see what they were like, My friend has a set on his Honda CB 750, They have threaded preload , 16 position compression and and 24 position rebound damping. The damping all works as it should and these are relatively easy to set up.    They should look good on the bike...  Also the shims for the front wheel bearings arrived, I can get pics of those later if anyone is interested.



 

And this is where mine sits at the moment with the front end fitted and the GS swingarm and my wheels and brakes....

 

I probably should have spread these posts out over a few days/weeks as I have to travel about 80 mile {120 Kilometers} round trip just to work on it ....

I've been a member of this forum for over a decade, and I don't think I've posted a single picture of my bikes. So here is my first project thread.  I'll give it a shot.  We'll see what happens.

This is my first Z1R (from 2009).


 


My dad had a ‘78 Z1R, which he let me borrow for my motorcycle license test around 1995. At the time I was between my first and second Kz650. Once I rode that Z1R I really wanted one. Such an unusual looking bike, and it rode really great. But at that time there really was no easy way to find one. To this day I’ve never seen another one in person (one that I don’t own).

It wasn’t until Ebay became popular that I started to see them for sale. I bought this bike on Ebay in 2001. I drove a box truck from Boston to NJ to pick it up. In person it wasn't as nice as I had hoped (digital pictures were low-res in 2001), but it was good enough. I rode it as-is for a couple months. In that time it stranded me twice with electrical gremlins, so I put it away for the winter. I had a Kz650 with the engine out at the time, and I decided I should probably put that back together before I ended up with two basket cases. Then 7 years passed. I did get the Kz650 back together, and gave it to my best friend (who I had bought it from 10+ years earlier).

So in 2008 I rolled the Z1R from my garage to my basement and did a bunch of work. I had the battery box and swingarm and other bits power coated. I replace the swing and steering bearings. I went through the entire brake system. I sorted out the electrical gremlins, which involved completely reworking the self-canceling turn signal system. I replaced a bunch of missing bits, swapped some aging chrome with better parts from ebay, and many other small things.

I bought it in 2001 with 41482 miles. When it rolled out of the basement in 2009, it had 41950. That right there is how you keep a vintage bike in top condition. Forget about it for 8 years.

I don’t ride the Z1R a lot. I’ve add about 4000 miles since I got it. I took it on a nice trip around the coast of Maine in 2010. In 2011 I got a mint 2006 ZR750S, which was cool except it had the worst seat ever put on a bike. Sold that, and found a 1995 GPz1100 mid-project with the head pulled off. Put that back together, rode it for a few years, and sold it in 2019. I also picked up a 2000 ZRX1100 but let that sit for 4 years without touching it. Oh, and along the way I picked up a basket case Z1R, and then my dad gave me his as well. But those are projects for some other thread.

At this point it’s been about 7 years since I last started the Z1R.

Now it’s time dust if off and get it back into good running condition. Of course I’ll need to redo a lot of what I did the first time. And get around to those things I forgot. For example, I’m embarrassed to say that somehow I never did a valve adjustment. I have no idea why not. Seems obvious. But I guess better late than never? I also never replaced the front tire, which based on the date code I think is from 1985!