The Kawasaki GPz Files, Part 1

Earlier this year in the pages of Motorcyclist I wrote a piece featuring Kawasaki's GPz550 series (CLICK HERE to see that story on the GPz550). The '83-spec monoshocker in that story was my personally owned machine, but don't let the fact that it was running and photographable at the time fool you; the thing had emerged from Century Motorcycles in San Pedro, California, just a day before the photo shoot, and would go back soon thereafter several times for even more resuscitation.

Just call it my latest used-bike-purchase mistake…

I go back to the very beginning with the red-and-black Kawasakis, having owned an '82 GPz550 during college in the early 1980s, and having first read about them in the magazines a year earlier. My monoshocker was a replacement for the Suzuki GS1000S I'd totaled a few months earlier on a local Utah canyon road, and it taught me much more than how much fun a modern middleweight could be; it showed me how much better a bike with 100 fewer pounds handled.

Anyway, I bought this one last summer after my latest GS1000S (I've owned several over the years) came apart for a total refurbishment—a repaint (stock colors, of course), an engine rebuild, and some period customization (black engine, wheels and fork legs) to turn it into a real Wes Cooley replica. (Note: the stock, blue-and-white GS1000S isn't a replica of anything Wes ever raced, so the nickname is a misnomer.)

I found this particular GPz on Craigslist in the Sacramento area. Sacto is 400 miles north of Los Angeles, but since I had some work to do up there anyway (and wanting to visit my buddy and sandcast Honda restorer Vic World), I figured I’d kill two birds and drive up and grab it.

The bike had looked great in photos, and it looked that way when I finally saw it in the flesh. It was all there, with nice-condition stock paint, not much patina, a clean title and a little over 20,000 miles. “Finally,” I thought, “here’s a nice one!” as most I’d seen for sale had been hammered and raced and worn out. This one ran, though roughly, as the carbs were gummed, which the seller, Mike-from-Sacramento, had mentioned. Problem was, it had more issues than wonky carbs, including a base-gasket leak that Mike assured me was tiny, but turned out to be anything but.

I can't blame him totally, because it's always a buyer-beware thing with used bikes, and no one forced me to hand over the money. But good ol' Mike did downplay things enough along the way to keep me satisfied that I wasn't buying a turd. And with him being a longtime motorcyclist and a fan of the magazine for many years, I sorta bought his shtick.

Once back home I yanked the carbs and took them to Century Motorcycles, which is the oldest still-operating motorcycle shop in the country, according to owner Tim. These guys specialize in older bikes, which isn't something you can say about the vast majority of today's new-bike dealers. There the carbs were cleaned, but when I got them back on the bike it still wasn't running right. And that tiny base-gasket leak I mentioned? It was now more like a boot/rear-tire oil shower. Ugh.

So I hauled the bike to Century, where it underwent something much more traumatic to one's wallet than a simple carb clean: a complete top-end disassembly and base-gasket replacement. A week (and a pile of Benjamins) later the bike was back up and running—right until the dumb vacuum petcock failed a week or two later, flooding the crankcase with gasoline. Ugh, again.

Back it went to Century, where the guys flushed the motor and replaced the petcock with an OE vacuum unit, as Tim and I couldn’t find a non-vacuum aftermarket piece that didn’t interfere with the tank bottom or carb top. I’m still looking for one, and I’m sure I’ll find one that fits well. But why the OEs used failure-prone vacuum petcocks still mystifies me.

Anyway, with the bike now running well (thanks, Century!), I discovered that the suspension is quite a bit worse than I'd originally thought. I expected the fork and shock to be worn badly due to the bike's mileage and age, especially given the fact that stock suspension in those days was always low-budget. But it's totally shot, the fork making noises and the shock pogo-sticking badly.

So off the thing went just the other day to Race Tech, which is always an excellent place to go for vintage (and modern) suspension work. There it’ll get a complete fork workover—firmer springs, fresh oil and some special valving, which always makes me think back to a phone call I got from Race Tech owner Paul Thede back in about 1991 or so. Thede called to tell me about a new product he was set to introduce, something that made a simple, damper-rod fork behave more like a true cartridge unit. He called it the Emulator, and would I like to try it out? Funny stuff. I believe he’s sold a couple sets of Emulators over the years, too. The shock is too cheap and cheesy to be re-valved, so the bike will get a brand-new unit, and maybe even a remote reservoir. Race Tech doesn’t currently stock a replacement damper for the single-shock GPz550, but they soon will, and it will be interesting to see how it works.

With its new Bridgestones, a solidly running engine and fresh suspension front and rear (Emulators, baby), I’m expecting my little red rocket to be a helluva daily rider. With my GS1000S project still several months from being bolted back together, and my CBX still in mothballs in a buddy’s living room (my garage is too small), the GPz will have to carry the load.

I’m just hoping it’ll make me forget about all the angst and money it cost me! And teach me to stop buying bikes on emotion.

Mitch Boehm, 53, began riding at age nine, and racing at age 11. His moto career includes staff stints at Motorcyclist (18 years), Cycle World and American Honda, plus he recently helped Malcolm Smith write his autobiography. All of which qualifies him to jabber away endlessly about old stuff.