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AC Sanctuary Modifies the Great Kawasaki GPZ900R


Kawasaki has been no stranger to the top rung of the performance ladder. One of the machines occupying that position was the GPZ900R introduced in the 1984 model year. It re-took the crown with horsepower and acceleration numbers that set new benchmarks for production motorcycles. You can see some original Kawasaki brochure language for this bike at the bottom of this article.

The accomplished Japanese customizer AC Sanctuary has produced this beautiful RCM-377 based in the GPZ900R. Known for getting the details right, AC Sanctuary produced a number of custom parts for this machine, tuned the engine and also bolted on vendor pieces from Brembo (brakes), OZ Racing (wheels), and Öhlins (suspension). With all the current interest in performance retro-style motorcycles, it is hard to beat AC Sanctuary’s take on this high performance classic.








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  1. Rocket says:

    I bought my Ninja 900 32 years ago. It still runs strong today. Bone stock except SuperTrapp exhaust and some carb work. Love this bike.

  2. NRHRetro says:

    Absolute work of art. A great example of a timeless design, they will be looking at pictures of the GPZ900R 100 years from now and it will still be considered a work of art. Today’s designers need to take a closer look at bikes like this. Last but not least, AC Sanctuary knocked this one out of the park, as usual, no one does it better.

  3. Paulus says:

    My current ride is a 1986 GPz900R, its tidy and original. I love it to bits but it has taken me a while to get used to its bulk. Great bike.

  4. Larry K says:

    Nice real world bike. For those (but not in the USA) wanting to be able to buy something like this check out the Triumph Tiger Sport. Pretty close..

  5. Artem says:

    Fuel tank was too small.

  6. Mgood3 says:

    That’s a thing of beauty!

    Hey Manufacturers- could we somehow get back to motorcycles that look like, well motorcycles?

  7. Gary says:

    I’ve always been a fan of the GPz. As a retro-mod it should loose the damping rod forks for a pair of proper USD forks.

    • Dirck Edge says:

      The ACS pictured has fully adjustable Ohlins forks.

      • Brinskee says:

        I don’t know Dirck, I think it would look way better with USD forks, and half of what these retros are about is looks.

        • bikeman says:

          I think Dirck was referring to Gary’s comment about the valving. Many (most?) modern conventional or “right side up” forks have cartridge valving (even way back to my 2002 Yami FZ1).

  8. Curly says:

    Never really cared for the 900 and still don’t. The plow nose fairing is just wrong. It did perform well but the looks always turned me off.

  9. Norm G. says:

    that exhaust is outta control. add some rainbow patina from the dyno and SHIP IT…!!!

  10. Grover says:

    This bike, along with the VFR750 were milestone motorcycles. It was the era of the modern motorcycle and a hint at the future. We still have these same basic platforms and Honda is even using their V4 in an adventure model. The biggest difference between then and now are electronic boxes that make life on a bike a little safer. Too bad Kawasaki has to put the”Ninja” label on everything, tho.

  11. Auphliam says:

    Now THAT is a fine Retro Mod. Enough with all these fake scramblers and crap. Give me one of these any day. Man, imagine the howl coming out of that 4to1.

  12. Andrew says:

    I think it looks great, and I say this as someone who is not especially fond of the early 80’s styling.

  13. Joe Bogusheimer says:

    I think it looks great. But then I was in grade 11 or 12 when the original hit the market, and owned a ZRX1100, so of course I do, LOL.

    • Joe Bogusheimer says:

      And I’ve also owned a ZG1000 Concours, whose engine is a direct descendant of the Ninja’s (by way of the Eliminator 1000, IIRC). My ZRX’s engine had a pretty close familial relationship to it, too.

  14. Austin ZZR 1200 says:

    Love the Darth Vader cowl

  15. redbirds says:

    Beautiful work. Bet it sounds as amazing as it looks.

  16. Snake says:

    As a prior owner of a 1984 ZX900 (GPz900 / Ninja 900) I not only approve of this, I’d buy it.

  17. jimmihaffa says:

    Hard to avoid gushing cliches, but ok if I can indulge…this thing is just so freakin’ cool. Kawasaki’s GPZ, Yamaha’s FZ and Suzuki’s GSXR ushered in the era of the true racebike for the streets. I think what makes the GPZ stand out more is that it was sort of the earliest evolutionary drift if you will in that direction, and as such it bears the closest similarity to its more conventional less focused street bike ancestor, the KZ. This bike transformed the definition of sport motorcycling that would follow, kinda like how Elvis transformed rock n’roll and that just makes it well…freakin’ cool.

  18. wtf_wonder says:

    The lines of the passenger seat are in total conflict with the rest of the motorcycle. THe all-black look is too modern. But, they bolted nice bits onto the bike and it’s nice to see the old steeds getting some love.

    • stinkywheels says:

      I respectfully disagree about the seat. Just opinions, but the seat is fine by me, and boy would I love to take little rip through the Ozarks with just an extra tshirt and unders.

    • Mick says:

      It looks like they trimmed down the front of the seat and left the pillion alone.

      I would have trimmed the rear down to the top of the tail section.

    • Tim says:

      I noticed the passenger portion of the seat as well. They should have rounded off the edges a bit. It doesn’t fit the rest of the design and draws attention to itself.

      That exhaust rocks.

  19. Provologna says:

    The bike is very nice. I too would prefer the OEM foot peg location. Paint wise the modified bike looks fine.

    The GPz900R outperformed Yamaha’s then race replica FJ1100. I only briefly rode both, and echo the general opinion of the day. The GPz outperformed the FJ in:
    Cornering clearance
    Engine smoothness (possibly the biggest upgrade margin of all these items, the FJ had a strong and wide range mid RPM buzz)
    Less weight
    6 gears vs. 5

    The Gpz felt less top heavy, and w/better mass centralization. Some still preferred the FJ for a wider/taller torque curve, but I preferred the GPz by good margin.

    I don’t think even a modern Superbike rider would consider the GPz a slug. I was shocked when I first rode it. This ACS version has must outperform a stocker.

    Well done!

  20. Brian says:

    Looks awesome. For my personal preferences, if they’d trimmed back the tail / passenger seat just a touch more, it would have been perfect.

  21. Starmag says:

    Beautiful and well done as always by ACS. They are the best in the world at this. I’d prefer the stock peg placement and paint scheme though.

    Just curious, how much?

    • Dave says:

      Re: “Just curious, how much?”

      I bet the way it goes is that you tell him you want a custom based on bike “XXX” with a style (muscle, cafe, retro, whatever..), then the builder goes and does his thing for a couple of months, then you go to get it with the mutual expectation that you’ll happily pay him whatever he tells you it costs.

      Or he just builds stuff without asking anybody what they want and sells to the highest bidder…

  22. notarollingroadblock says:

    As a huge fan of early 80’s bikes (and any nice “standard”) I’m really liking what they’ve done there. Thanks, Dirck.

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