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The Paddock
The Springfield Mile here in Central Illinois is one of the most famous one-mile dirt racetracks in the country. I'm sure it was built for horses but motor racing made it famous. When we moved here last summer I looked forward to seeing both four- and two-wheel racers go at it on the dirt.
Due to some biker bash problems years ago the motorcycle races aren't promoted locally so I missed them last summer. I did go to the USAC Silver Crown race and had a great time. I was disappointed to learn the motorcycle race this year ran the same day as the Indy 500 which I couldn't miss. Reading the newspaper on Monday morning, however, I found out rain had caused the bike race to be postponed a day so I could go after all.
I left the house about 7:30 am and was at the Illinois State Fairgrounds 10 minutes later. It was overcast and cool enough to need an overshirt, but would be sunny later. Several hundred people were already on hand and expensive motorcycles were everywhere.
I found the office and a nice lady gave me a media pass and a race program. After a short walk through a tunnel under the main straight connecting the grandstands and the infield, I found myself in a paddock full of pickup trucks, small trailers, motorhomes, racing motorcycles, and guys in leather suits.
Michelle DiSalvo from Waterford, Calif. rode in the H-D Sportster class, a support series to the Grand National Championship.
Chris Carr, the reigning national AMA champion, poses on his motorcycle during a taping for TV.
Chris, a former TVM subscriber, remembered me from when we both lived in Northern California. He introduced me to his crew chief and team manager, Kenny Tolbert, who was kind enough to answer my usual array of questions. That's Kenny with Chris sitting on the rear bumper of their truck.
Kenny was kind enough to answer my usual array of questions. I started by asking about the engine which Kenny builds himself, "Some tracks you have to go slow to go fast, if you know what I mean," Kenny said, looking toward the V-twin Harley-Davidson racing bike sitting on a jack stand right next to us. "Chris is an aggressive rider and I have to detune the engine so he can get some bite. I do that with ignition timing and carburetor tuning. The engine has dual-plug heads. The carbs are Mikuni with slide throttles. We use race gas and have to meet noise limits at all the tracks.
"The chassis we use hasn't changed much in the last 20 years. The brake is on the rear only. We use KYB front forks that are stock on the Yamaha R-6. The shocks in the forks are double-tube.
"At the rear we have remote-reservoir, double-adjustable Penske shocks. This bike has shocks with a digressive piston. The spare bike is setup with shocks using a high-flow piston. Different drivers like different shock setups. [Just like four-wheel drivers.]We also use the preload on the springs as a tuning adjustment."
I can see the shock is tucked up in front of the rear wheel below the rider's seat. There's a linkage mechanism but engine intake filters and exhaust headers keep me from locating all the pivot points. Kenny tells me the motion ratio is 2/1, wheel/shock.
"Several companies supply tires: Goodyear, Dunlop, Continental," Kenny says. "There are two different compounds per brand. We'll use the hardest compound here to keep from blistering tires. The sun will come out later and this track will get a coat of rubber just like pavement. For the race we'll probably have to cut some heat sipes into the tire tread."
I asked Kenny about geometry adjustments. "The head angle is fixed because the head tube is welded to the frame, but an eccentric bushing lets me change the fork offset to adjust the wheelbase."
How do you determine what adjustments to make? "Chris tells me. He's riding the thing."
Any titanium parts? "The pivot bolt where the rear suspension arms attach is titanium and so are the exhaust megaphones. And some engine stuff. But not much. We're not allowed to use titanium for axles. They have to be magnetic material [steel]."
How important is the preparation of the track surface? "They're out there with trucks running it in for us now. That's good. There'll be less mud and spray later."
Rich King was the only rider to have FOUR bikes at his disposal. He's the Harley-Davidson factory rider. Just right of center sits Bill Werner, the most famous bike tuner in the U.S. He works exclusively for H-D.