I wrote this article about 2000, about building and racing my 1986 Kawasaki GPz 600R.  This is the bike (and the St. Louis race) depicted in the old photo of me on the facebook page.  It was published on a British Motorcycle racing website.


Preparing and Racing An Old GPz in the Twenty-First Century

by Andrew Mishlove

Allow me to introduce myself. I’m a middle-aged lawyer from middle America. But it just so happens that I live close to two great racetracks: Blackhawk Farms Raceway and Road America. Ten years ago I accidentally caught the sports car racing bug, and try as I might I haven’t been able to shake it. Since, my MG Midget is long gone and my LolaT440 is bent, I have gleefully and foolishly turned my attention to motorcycling.

My first project was a vintage racing 1972 Honda 350, completed over the winter of ‘99. I got into this because I thought I could do it on a budget. It turned out to be the budget of a small European country; but, oh well. The Honda was given a screamer of a motor: Big bore kit, megacycle cams, etc, etc. After the profusion of oil leaks were stopped, it stylishly got me through rider’s school and a couple of races. It now adorns my front room as an object of art.

The problem was that there was only current-era racing in my area, not vintage racing. Imagine me, an oversize graying barrister, campaigning this vintage Honda against brand spanking new Kawi 500’s and such-like. They blew by me so fast that it peeled the paint of my petrol tank.

I Meet The Geepzer

As I had a little more money than brains, I thought about getting a faster bike. I compete in the CCS Mid-West Series in the Sportsman (more or less entry level) and Formula 40 (old farts) categories. Modern crotch rockets of the 4 cylinder, 16 valve liquid-cooled variety are not allowed in Sportsman categories. There’s a loophole, however. Old crotch rockets, circa 1986 or earlier, are allowed.

One day while ogling a brand new SV650 I noticed an old bike languishing in the dealer’s storeroom. This thing was, literally, on a shelf, eight feet off the floor. I eyed it as I would a pretty girl sitting alone at a dance:  my 1986 GPz600R. The dealer had taken it in on a trade two years earlier. He showed me the receipts and work orders for the new valves, rings, etc. But it had been sitting for two years. No one wanted the old girl; and it was no wonder, since he wanted $2400.00 for it. I told him I’d make an offer if it passed a compression test. He didn’t want to be bothered. So I took a chance. $800.00 poorer and one geepzer richer, I loaded the bike in my van and headed home.

If stored properly, a two-year old rebuild could be just fine. But in two years it could also be seized. I charged the battery, gave it some fuel, and VIOLA. It ran, and nicely too. I got lucky. Now, for the race prep.

The Modifications and Tribulations

The one thing I didn’t want to do to this bike was rebuild the motor. It’s way too easy to put more money into a motor than the cost of a brand new bike. This motor would not be opened if I could help it. But, the rest of the bike would be updated.

I got a lot of ideas perusing the internet. Race preparation starts with stripping, cleaning and getting rid of all non-essential parts. This, I did. All lights, signals, inner fairing, speedo cable, side stand, rear foot pegs, non-essential wiring, etc., were trashed. Also removed was the charging system. I’ll run total loss, and recharge between sessions.

I didn’t like the way the fairing looked with a plastic cover over the headlight hole; so, I splurged on a “race” upper fairing and solo seat cowl from Airtech (www.motorcyclebodywork.com). I sprayed the thing myself from aerosol cans, and it turned out pretty good. $50.00 recovered the seat at the local upholstery shop. The CCS required belly-pan was fabricated from light sheet metal and pop-riveted to the lower fairing for negligible cost.

I was especially proud of the straight pipe exhaust system I made by welding electrical conduit to the header. But this was discarded in favor of a proper 4-1 Yoshimura due to air velocity concerns. Luckily I was able to get a new, blemished Yoshi.

Speed is equally dependent on three things: horsepower, brakes and cornering. I turned my attention to the latter. The suspension was heavily massaged. This is where I put the money. The antiquated antidive was removed and blanking plates fabricated. Racetech springs, valve emulators, bushings and seals were installed. The Works Performance shock that I installed was so good-looking that I hated to put in on the bike. At least I had the Works Performance sticker for the fairing.

Removing the antidive got rid of a tangle of brake lines and unsprung weight. The shorter, more direct stainless steel braided lines really firmed up the braking (only about $45.00 for all the lines from Behling Racing, a Milwaukee stock-car racing supply house). Calipers and cylinders needed only a good cleaning. Ferodo race compound pads give great feel. So, for relatively few bucks, the brakes were vastly improved.

Avon AM23 tires were the stickiest that I could find for the 16” wheels. They seem fine to me, but I doubt that they’re the equal of the latest 17” stickies from Michelin and Dunlop. I put the brand-new Dunlop 591’s that came with the bike in storage. I would welcome a stickier pair of tires; but I just don’t know if any are available.

To aid in breathing I opened up the airbox and fabricated a new air cleaner using duct tape and a cleaner from my Formula Ford. I was to find out, that was a big mistake.

The Tribulations, or Argghh, It Won’t Rev.

Now the thing looked great and was ready to test. Charge the battery, add petrol and…

Please excuse the following explicatives. But, oh shit! It started, it idled, but it wouldn’t rev. I must have rejetted the thing ten times. I had the carbs off so much that the screw heads wore out. I replaced the clamps and inlet rubbers (highly recommended anyway). That’s when I trashed my home-fabricated exhaust and got the Yoshimura. But, it didn’t help (although, it looked cool, and was lighter). One thing I noticed was that the slides were not moving in their bores when I turned the throttle, indicating a vacuum related problem.

Then, I noticed a telltale sign in the oil. It was frothy. Oh shit, again. Now I had to tear down the motor. Off came the head and cylinders. Careful inspection revealed that the work done by the dealer was bodged. Although the valves, rings and cylinders were great, the head wasn’t flat. It was out by .007”, which is way too much. The head gasket was blown. The head had to be milled; but at least all the valves were intact. That wasn’t so bad. A new head gasket, a few hours timing cams, adjusting valves and it was ready to go.

Oh shit again and again. It still wouldn’t rev. I had to break down and send it the local race shop for dyno testing. Vintage race ace Tim Schneider of Milwaukee told me all along that my beautiful custom air cleaner was the problem, and he was right. We wound up “tape-jetting” the thing. Using the dyno, we covered the air inlet with duct tape until it ran right.

And boy, does it ever run right now! It really screams! This bike is so sensitive to air velocity changes that when a little flap of duct tape came unstuck from the air cleaner, it wouldn’t rev anymore. When I put the tape back it ran great again. I suppose that the correct way to do this is with a proper K&N/Dynojet kit. The steep price is well worth the engineering.

The First Race

The first race on a newly prepared vehicle is always scary. There are so many questions. Will the brakes grab or fade? Will I have grip? Will it shake or shimmy? Will it rev? Will I live? I was to find out the answers on March 16 at Gateway International Raceway in St. Louis, about 400 miles from my home.

A long day spent loading the race bike and tackle into my van lead to a long drive to St. Louis. Six hours of fending off double-bottom trucks (lorries to you) in a hard, freezing rain. My white-knuckled fists had to be pried from the steering wheel when we finally arrived.   St. Louis is known as the “Gateway to the West,” and was the starting point for the American westward expansion of the nineteenth century. As a memorial, there is a huge triangular stainless steel “gateway” or arch, almost one thousand feet high, visible for miles. It is an architectural wonder. Good architecture evokes emotions; and this thing soars! You can feel it when you stand next to it. Although it sits in what appears to be a placid meadow, there is actually an underground museum beneath it. Much of the museum is appropriately devoted to the tragic treatment of Native-Americans during the westward expansion. This was really fascinating and well worth the time. We would have taken the tram to the top; but we had to get back to the track.

The bike was GREAT! The motor pulled and revved. The thing cornered fine. The brakes were fabulous. I, the rider, was definitely the limiting factor. I couldn’t believe how fast those young guns were riding, especially in the rain. I can say with certainty that in car racing the machine is a much greater factor than in motorcycle racing. In motorcycle racing, the rider is, by far, the most important thing. I came in sixth and last across the finish line, but ahead of the seven much faster guys who crashed out behind me. Old age and discretion worked better than youth and bravado on this cold, wet day. I’ve got a long way to go, though. Another rider’s school is on the menu.

The Season Ahead

Heaven willing, I will run a full season of races this summer. In order to do that, I have certain mechanical and personal goals and concerns. To be a successful racer requires the same type of organization, commitment and self-discipline that it takes to succeed in all of life’s endeavors. I define success not only as winning or placing, but also as bringing to the track and your life the qualities of excellence. Anyone who does this is a winner, no matter where they place. Motorcycle racing is an athletic sport. So, I am going to focus on physical and mental fitness and organization, to prepare myself for the season.

Question: What is a season’s race budget?
Answer: The thing that you blow in the first two weeks.

Part of the aforementioned physical and mental fitness and organization is budgeting. It’s hard to act like a grown-up on a budget when you are actually playing a foolish child’s game. But, I resolve to do it. It makes no sense to blow it all early in the season. Not only that, budget fabrication leads to some of the most ingenious engineering (although, it also leads to stuff like my air cleaner debacle).

Mechanically, I have a few concerns. Since I’m racing against new bikes, (mostly SV650’s) I have to find some more horsepower. The K&N/Dynojet kit is on my wish list. Also, the bike really will overheat when revved really hard. The old hands tell me that this was a common problem with these bikes back when they filled the grids. I fitted a small supplemental radiator (actually a small oil cooler plumbed into the cooling system) mounted in front of the stock unit. I hope it works. I’m going to reinstall the thermostat, in case it works too well. Also, I found a couple of broken teeth on the water pump drive gear. Luckily, the teeth themselves were still in the water pump housing , or I would have had to go on a messy search inside the case. The tires and tire pressures are an obvious concern. That will have to be tested.

Costs on the project are as follows. See you at the track!

1986 Kawasaki GPz600R:
  $800.00.  Racetech springs, valves, bushings and seals: $300.00 Works performance shock:
 $580.00.  Avon AM23’s, installed:
 $225.00 Chain:
 $100.00 Airtech bodywork:
 $300.00.  Seat upholstery:
 $50.00. Paint:
  $50.00.  Head disassembly, milling, re-assembly: $170.00. Yoshimura 4-1 (new, blemished):
 $200.00 Ferodo pads and steel lines
:  $105.00.  Inlet rubbers and clamps:
  $80.00.  Head gasket:  $40.00.

$2290.00, American. Not bad.