FEATURE – 1974 Kawasaki Z1A custom
Words: Mike Ryan
Photos: Ben Hosking
Restorations of classic motorcycles are great for a number of reasons. Firstly, they keep old bikes alive and ensure makes and models from the past are not forgotten. Secondly, they keep a number of specialist services and component suppliers in business, and that’s got to be a good thing, too. Finally, they enable professionals and backyard builders alike the chance to develop their skills in areas from welding to fabrication, electrics to painting, engine building and more.
That being said, restorations do have their restrictions. Bringing an old bike back to its original specification means these projects can really only go in one direction - the path is set and once you’ve done one resto, you pretty much follow the same path again for the next one.
Custom projects have no such defined path, so the route to the finished bike can take any number of twists and turns.
Brett Brown has been down that “fixed path” of factory-authentic restoration many, many times.
“Restos are great,” Brett clarified. “I love them and I’ve done many myself, but when doing factory-spec restos, you’re just building the same bike over and over, following a set plan where everything fits and all you have to do is assemble – it’s too easy and not very challenging.
“Also, not all bikes are good candidates for this and we should remember how bikes were, especially in the Seventies. They often didn’t stay standard for long.”
That Seventies connection is important, but we’ll get to that in a minute.
In applying his impressive skill set to custom builds, Brett’s been taking his creativity in new and unusual directions recently, but still focused on his beloved Kawasaki Z1s.
The path to these unique machines may be more challenging at times, but for Brett, it ultimately brings more satisfaction.
Turning to ‘Stone’
Brett should be familiar to regular JUST BIKES readers, as he was the man behind the stunning Rau-framed Z1 custom that featured in issue #314 (July, 2015).
Coming after numerous Kawasaki Z1 restos, that complicated and finely-finished project proved that Brett could combine artistic creativity with engineering practicality.
“What I realised when building the RAU was that I really enjoyed being able to be creative again and put something of myself into the bike,” Brett explained.
It was that creativity that led him to build the bike featured here: a modified Z1A, built as a tribute to Stone, the classic Aussie bikie movie from 1974.
Brett brought the finished bike to our attention early last year, but it had been bubbling away for a long time before that.
“The idea came to me about three years before I actually started. I was busy doing restos, so finished what I was doing before I started this.”
But why Stone as the theme for this build?
“Because I`m old enough to remember when the movie was released,” Brett laughed. “The effect it had on Z1 enthusiasts at the time, in my circle and the wider motorcycling enthusiast community, meant it was common to fit Stone fairings and have custom paint jobs done to imitate the movie.”
Brett added that a mate of his owned one of the actual Z1s used in the film and it was this unit that partly inspired the finish his bike wears.
Hardcore fans of Stone will instantly identify that this bike isn’t a clone of any of the Kawasaki Z1s used in the movie, but its fish-scale paint finish is probably closest to the bike ridden by ‘Stinkfinger’.
“I didn’t want to copy any of the bikes exactly, so I did it in Jaffa colours and put the Grave Diggers patch on the tank to be more suggestive of the whole movie.”
The paint and detailing in tribute to Stone are just part of the story with this build, though.
Bigger Muscles, Stronger Bones
Found online, the unit Brett started with was a 1974-model Z1A. A non-matching numbers example, the bike had been messed with in too many areas for a resto to be feasible, but it did have an early-number Z1 engine, which was set aside for another project. A later Z1B motor was sourced to replace it.
“I bought the motor in pieces, but it was in good shape,” Brett explained.
Checked carefully, the engine was then upgraded to 1000cc spec with a bore increase to 70mm, matched to a set of Z1000 crankcases sourced from the US and fitted with an Andrews cam with a mild 1X profile.
Being a Z1B engine, it had a natural alloy finish, instead of the black of the original Z1. That, in turn, meant a lot of alloy polishing would be on the cards, but Brett took a different approach here.
“I’m tired of polishing alloy!” Brett laughed. “I didn’t want a bike that had to be continually polished, so all the outer engine cases are chromed, as is just about every other metal part of the bike that isn’t painted. It cost a fortune, but it has removed the need for future maintenance of the polished alloy.”
Capacity increase aside, the engine is largely stock. The Lockhart oil cooler is a handy inclusion for our climate and one that Brett says was a common aftermarket upgrade back in the day. The 4-into-4 pipes are all originals, made up of a combination of Brett’s own stash and used units sourced from Old Gold Motorcycles.
The frame and back end needed more work than the engine, and it was here that the project got more complicated.
“The frame had big ugly plates welded over the gussetting below the steering head where they often crack. There was also other bracing that had not been done very well.”
Cutting and grinding all that off, Brett used steel tubing rather than plate steel for the new bracing, and triangulated it in all the key areas, applying what he’s learnt from past projects.
“This frame is now just about the most heavily braced Z1 frame ever,” Brett said. “Z1s that are ridden hard are well known for cracking the downtubes just below the steering head. I`m confident that won`t happen to this bike!
“I also wanted to make the bracing a feature in those areas where it is visible and plate looks pretty second rate.”
Additional to this bracing, Brett also fabricated new, stronger engine mounts to more rigidly set the upgraded powerplant into the frame and reduce flexing even further.
An early plan to apply similar bracing to the factory Kawasaki swingarm (another known weak point in the early Z1s) was abandoned, with Brett committing fully to the custom path by sourcing a longer and stronger swingarm off a Suzuki GSX 1100 from Old Gold Motorcycles.
Brett explained that this box-section swingarm is much stronger than the factory Kawasaki tubular unit and fitted the frame well, with only a few spacers needed. It also allows the fitment of a larger rear wheel, in this case a 3.50x18-section rim. The front rim is wider, too, and Brett re-laced both units himself before new hoops – Avon front and Bridgestone rear – were fitted.
To match this swingarm, Brett ordered a pair of Ikon shocks with a clevis mount. Compared to the original units, the Ikon shocks offer significantly better damping, but thanks to the use of chromed Z1 spring covers, they still look factory.
Seventies meets the Noughties
The upgrades and modern thinking in this build didn’t end with the engine and frame. The stopping power has been upgraded with the addition of a second front disc. Brett says this was a common modification in the ‘70s and it’s a welcome one in this instance, given the extra engine power, but Brett has increased their effectiveness further with drilling.
“Stainless discs from that era lost all friction in the wet until the pads had cleared the water off the discs,” Brett explained. “More than once on Zs with undrilled discs, I have been unable to stop at a red light in the wet and continued into the intersection – scary stuff.”
At the rear, Brett chose to retain the factory rear drum brake. It may seem a curious decision, but he believes the drum performs better than the discs fitted to later Z1000s.
Back when it was new in 1974, a Kawasaki Z1A produced 82hp (61kW), and while he hasn’t put his bike on a dyno, Brett’s pretty confident his upgraded creation delivers around 95hp (71kW) in its current state.
More importantly, the bike handles much, much better than a ’74 Z1A ever did.
“As I was hoping and expecting, the bike handles great,” Brett explained. “I can`t induce a wobble no matter how hard I try. Usually, if you go into a corner too fast on a standard Z1 and hit a big bump, it will give you a death wobble and try to kill you because the frame and swingarm flex - not this bike!”
Stone Satisfaction
A year in the making, Brett says he couldn’t be happier with how this bike turned out. It was time consuming, and also expensive for the few elements he didn’t do himself, like chroming and powdercoating, but worth it.
Since completion, the bike’s been used sparingly, but Brett says it always draws a positive reaction when he takes it out: “I’ve had drivers try to pull me over to chat, I get thumbs up from other riders and it draws a crowd when parked – it’s a bit embarrassing, really.”
This bike has drawn a lot more attention than Brett’s factory-spec Z1 projects, which he puts down to the custom paint scheme he executed himself.
That paint is a candy metalflake in the iconic ‘jaffa’ brown and orange of the original Z1. The paint’s depth and sparkle is hard to capture on camera but it looks great to the naked eye.
To most punter’s eyes, it’s just an old-school paint job and only a few older riders and Zed heads make the connection to the film when the see the ‘Stone’ name on the tail and the Grave Diggers logo on the tank, but Brett says that’s cool.
If the new owner of this custom Z1A was introduced to the film via the bike, that’d be even cooler.
In helping to bring his Stone tribute to life, Brett thanked the following:
The Chrome Factory – Caringbah, NSW
South Coast Powdercoating – Unanderra, NSW
Old Gold Motorcycles – Londonderry, NSW
FOR SALE
With this build done, Brett’s got other projects on the go, mainly Z1s, of course, but there also are some equally classic Honda CBs due to receive attention from his talented hands.
As such, this unique Stone tribute is now for sale.
The bike has only covered 600km since the project was completed last year, so is still fresh. Currently unregistered, Brett did have it on full registration briefly and it passed approval easily, so getting it registered shouldn’t be a problem for the new owner.
While the appeal for Stone fans is obvious, this bike has a broader attraction as a finely-executed example of a customised classic Japanese motorcycle. Beyond looking good, the frame strengthening, brake and suspension upgrades means it rides good, too.
Asking price is $27,000 ono.
Call Brett on (02) 4423 2814 for more details. See the ad in this issue, or online at justbikes.com.au with the ad code JBM5033386
About Stone
While one of Australia’s most successful films in terms of return on investment, Stone is also one of our least known. Sure, it’s an icon amongst the (older!) motorcycle community, but most people have never heard of it.
Released in 1974, Stone tells the story of a bikie gang, the Grave Diggers. When a political assassination is unwittingly witnessed by one of the Grave Diggers, the hitman then starts murdering gang members to cover his tracks. That leads the police to send in ‘Stone’ (whose first name, interestingly, is never revealed) to join the Grave Diggers and try and identify their attacker.
It’s no Donnie Brasco-style undercover story, though, as Stone declares he’s a cop from the outset, but nevertheless wins the Grave Diggers’ trust.
When the hitman and his cronies are caught by the gang, Stone intervenes to prevent the bikies dispensing their own form of justice. Leaving the gang behind and returning to regular police work, Stone nevertheless retains respect for the Grave Diggers, despite a compelling argument to do otherwise in a brutal finale.
While that’s the plot, Stone is really a 95-minute celebration of the bikie lifestyle: the freedom, the parties, the camaraderie and the simple enjoyment of riding.
The fictional gang were a bit different from the norm, though. In an era (the 1970s) when bikie gangs still rode Harleys or British bikes almost exclusively, the Grave Diggers all rode then-new Kawasaki Z1s. Each member’s bike was custom-painted and featured individual finishes more often seen on panel vans than motorcycles back then.
If you’ve never seen Stone, do yourself a favour and check it out. If you haven’t seen Stone for a while, fire it up again. It’ll give you a newfound appreciation for the film and a greater respect for this bike that’s been created in tribute to it.
Incidentally, the title of this article – Take the Trip – was the slogan used for the film.
