Obsessive Behaviour

Steves 1975 Z1B

Click any image for large / small view

You cant beat the classic styling of a Z1
Part 1

Kawasaki 900's and I go back a long way. My first road bike was a brand new 1976 Z900 which cost me $2,200. How times have changed. To a get a state of the art Japanese road burner these days you have to spend 10 times that amount. I also had an immaculate Z1 Jaffa in the early eighties. Rode that thing from Dubbo to Perth and all about. I should never have parted with that bike. The Z1B featured here was bought in 2001 when I returned to Perth after a couple of years in the Eastern States.

She was in pretty good nick for her age. However, a few things had to be fixed immediately as it was my only form of transport at the time. When I test rode the bike it was not running too well Not a problem said I. All she needs is a quick tune up. I was in lust, I just had to have it. After a couple of days of missing and farting about the place I decided to set the ignition timing and sync the carbs. This is when things started getting expensive. First up, I could not get the timing right no matter what I did. The mechanical advance mechanism had worn so badly that the timing jumped all over the place. That problem was easily fixed by tossing the lot out and fitting a Dyna 2000 ignition with electronic advance.

Now that the timing issues were sorted it was time to sync the carbs. What should have been an easy job turned out to be impossible because the linkages in the carbs had packed it in. The solution, fit a set of 34mm Mikuni flat slides using Kawasaki Z1000J manifolds. The air filter box had to go and was replaced by a big set of tapered K&N's originally designed for a Suzuki GS1000. I had to grind away some of the side covers to get these to fit. That was a scary job, I was not too happy about attacking the covers and possibly ruining the nice paint work. Luckily it worked out well.

No more ignition worries
Carby problems sorted
The bike had a good set of standard pipes so I put these in storage and fitted a set of Magnum/Transac 4 into 1's with a carbon silencer. I also had to relocate the rear pegs as they got in the way of the pipe. The seat was looking a little sad, so I sand blasted the base, welded up the rust and gave it a shot of black paint. I then replaced some of the damaged foam and fitted a replica seat cover. All of this was a major drama. I hate reconditioning seats, its a real pain in the arse (no pun intended). Anyways, it was worth the effort. Now I had a good looking and reliable ride. Only one problem left, a small but annoying oil leak around the head gasket ...

I have now had a couple of years good service from the old Z1. Unfortunately that oil leak has got progressively worse so its time for a top end job. The finish is looking a little tired so a bit of restoration work is required. A high priority is an upgrade to twin disks. The stock unit squeals a lot but doesn't do much else. The el-cheapo exhaust is already starting to rust so I think I will get a set of real pipes in stainless. Maybe they will make enough noise to cover up the annoying rattle of the flat slides. Think carefully before fitting flat slides. They work well, but make the bike sound like a dry clutch Ducati.

© Steve Harrison 03/03/2004

It was worth the effort
Part 2

Well, 16 years have gone by since I wrote that article. I suppose I had better finish the story. At one stage the bike had been restored so the paintwork, instruments and guards were in pretty good condition. I had already taken care of the seat. Everything else was starting to look a little rough.

A lot of bolts had been re-chromed and polished within an inch of their life. The corners were so rounded that you could not use the correct size spanner. The zinc plated fasteners had been touched up with silver frost (rubbish tin silver) and had started to rust. The black paint on the frame and fittings was dull and chipped with surface rust. The rims, spokes and exhaust had started to rust. All the alloy surfaces were dull, scratched and corroded. The rubber fittings and wiring had fossilised and gone brittle. She certainly needed some love.

My plan was simple. I wanted it to look like I had taken a brand new bike off the showroom floor and added a few tasteful upgrades. My first step was to take a heap of pictures so I could work out where all the wiring and cables went when it was time to put it back together. Then I stripped it completely, right down to the last nut and bolt. Man, that was a lot of parts. Good thing I took all those photos.

Nothing spoils a restoration like rusty fasteners. From the outset I resolved that every nut, bolt, washer and spring was going to be replaced or re-plated if it was in good condition. Where possible, I would use polished stainless Allen bolts. Every rubber grommet, damper or doobrie would be replaced with new reproduction parts. This bike was going to shine.

A lot of PMC goodies went into that bike. I had just set myself up as a dealer and needed a couple of big orders to establish my account. Perfect I thought, what a great excuse to spend a stack of money on my bike. Let’s call it a business expense. Now that I had found a way ease my conscience, I launched myself into the project.

A word of warning about stainless fasteners. If you use a stainless nut on a stainless thread you may run into a problem known as thread galling. This can cause the nut to seize. It’s a good idea to use anti seize on all stainless fittings. I use Loctite 771 Nickel compound. Stainless can also react with Aluminium causing corrosion. I use a Nickel based anti seize when using stainless fasteners on Aluminium cases. If you don’t have anti seize then at least use a little high temp grease. The idea is to lubricate the threads and keep moisture out of the joint. If the manual specifies a thread locking agent then this should be used instead. Thread lockers also help prevent galling and corrosion. Here endeth the lesson.

My plan of attack was to build the bike from the ground up, so I sent the frame and swing arm out to be powder coated. It came back looking fantastic. However, that stuff is like melted glass. I had to run a tap through every thread on the frame. The coating was so thick that the swing arm would not fit without me filing off the paint on the inside of the frame. You cannot scrape that stuff off, it’s bloody hard. The last frame I had powder coated was a Suzuki GT750 way back. I seem to remember having the same problem with that as well. Maybe next time I will use 2 pack.

Anyways, the frame cleaned up well, it looked great and the paint will probably last forever. In an effort to reduce the wobbles, I fitted a set of tapered roller head stem bearings and needle roller swing arm bearings. The existing Koni rear shocks were given a detail and came up like new. The bottom triple clamp was painted with a gloss black Wattyl Killrust spray can. This paint provides a good durable finish if you give it plenty of time to cure. The top clamp was done with VHT satin black case paint. I have used this stuff for years. To get a factory finish, let the paint dry for a couple of days. Then put the job in an oven and bake at 100 C for 20 minutes. I would not use the kitchen oven because it does stink and the Mrs will complain.

Then it was on to the front suspension. The fork inner tubes were in perfect condition, so that was a bonus. I polished the alloy fork legs to a mirror finish then fitted new seals, dust boots, reflectors, progressive springs and top caps. Then I had to make a new set of studs for the axle clamps because the old ones looked stretched and decidedly unsafe. End result, one brand new shiny set of forks. I must have spent a week in front of the buff polishing all the covers on that bike. Talk about a filthy job.

Getting close now
I could not put if off any longer, it was engine time. I had no idea what a can of worms I was about to open. I found stripped threads, broken off bolts, a broken exhaust stud mount, a flogged out clutch hub and a cracked head. The broken fin I already knew about. This was going to be fun. After much drilling, tapping, a few helicoils and some specialist aluminium welding the head was as good as new. Along the way it also picked up a new set of valves, guides, heavy duty seals and camshaft bearings. The barrels were bored for the new Wiseco 1015 piston kit and a new cam chain, tensioners, rollers etc were installed. The top end was now held down by a set of heavy duty cylinder studs and billet head nuts. New transmission bearings and seals were fitted, the clutch was rebuilt and the gear shift shaft was replaced because the spline was stuffed. I even re-plated the kick starter shaft so it would look like new. How’s that for obsessive behaviour.

One of the most labour intensive parts of the engine rebuild was the painted finish. At the time I decided on paint because I was worried about the cases corroding and wanted an easy care finish. The plan was to ride this bike. I decided to bead blast the engine and paint it with VHT silver case paint. Blasting the engine (especially the top end) was a tedious job. Cleaning all the grit out of the blind holes in the cases was even worse. Painting was also a hassle. It was very difficult to get an even coating down between the fins without flooding the high spots. In the end it turned out fine, but it was not easy. I am over painted engines. Next time around I will vapour blast and go for a natural finish. A hell of a lot less work.

While the top end was being rebuilt I turned my attention to the wheels. Chopping out all the rusty old spokes with a bolt cutter was very satisfying. The hubs were cleaned up, painted and fitted with new bearings and seals. Then out they went to be laced up with new spokes and DID steel rims. Since I had the frame sitting on the floor, now was a good time to fit the engine and forks. The wheels came back with nice new tyres so I bolted them up and got the bike off the deck. Woo Hoo, I now had a roller!

Riders view has definitely improved
I was in such a hurry that I forgot about the second disk. Not to worry, I had to overhaul the old caliper and fit pads to match the new one. At the time I already had one good disk so I ordered another for the right side. If I was to do it again, I would bite the bullet and buy a set of drilled front disks. I was in so deep at that stage that the extra expense would not have mattered. Anyways, I now had a twin disk front end. It was all good.

Things were now coming together in a rush. The engine top end went back on along with a flash new PMC straight exhaust. That pipe was a work of art in stainless. It’s a pity that they are no longer available. I was tired of the rattly flat slides so on went a nice set of Keihin Cr’s. The old wiring was in a sad state so the entire electrical system was updated with new wiring looms, switch gear and an electronic voltage regulator. The battery box and electrical plate were given a coat of Killrust gloss black and installed with new mounting hardware and rubbers.

As I said before, the clocks were in good condition. All I had to do was respray the lower covers and mounting bracket with satin black. The warning light cover and wiring harness were replaced. The bike did not have matching keys, so I took the opportunity to install a new lock set. New brake lines and cables were fitted. In an effort to improve braking I decided to go with a modern Nissin 5/8 remote reservoir master cylinder. Then it was off to the local Kawasaki dealer to see if I could find a clutch lever and bracket to match the adjustable dog leg setup on the master cylinder. It turned out that a ZX6 lever was an exact match. Since I have issue with heavy controls, I fitted a PMC easy clutch release kit. That made a big difference. The final touch was a nice set of Aluminium superbike bars and grips.

After all of that, I have to say it was well worth the effort. I loved that bike and it drew a crowd wherever it went. People would get all misty eyed and say “I remember when”. In my opinion the 70's was the golden age of motorcycling in Australia. You know how it is, you turn up with a helmet and jacket and people ask "what do you ride". You tell them knowing that they will be none the wiser. Back in the day, all you had to say was a "Kwaka 9". It didn't matter if they rode or not, The Z1 was the absolute king of the road and everybody knew it. If you are lucky enough to own one of these old beasts, you know exactly what I mean.

© Steve Harrison 05/04/2020