This spring, I got my old K&L dyno working very well with new software from Performance Trends and used hardware from Jack Illiff. I had to build a starter mechanism which consisted of a Dodge starter motor with a polyurethane drive wheel mounted on a shaft behind the rotating drum. It worked very well and started my bike every time with no problems. So then the only problem was slowing the drum down which still requires the use of the bike's rear brake. Not too bad with the disc brake as the pads are easily installed and cheap, which I already had to do once. I didn't know the rotational moment of inertia of the drum, so I worked backwards using a 100% stock Yamaha SR100 which was claimed by Yamaha to have 31.5 hp. When I got the dyno reading to indicate 31 hp for the Yamaha, I started testing a couple of my other bikes.
I then put on a stock BSA B50 with a new piston, and after having to retune that, I managed about the same hp as the Yamaha, though BSA claimed 34 hp. A stock BSA B44 with a new piston registered 28 hp, so I felt I was getting a reasonable number. I then put the land speed bike on and got an amazing 62 hp. To qualify that number, the last time I had the bike on Dan Dunn's Dynojet dyno, it only registered 50 hp and I hadn't made any significant changes, so the 62 hp number is "happy horsepower", but it's all relative when I make changes, and it is nearly twice the hp of a stock B50.
I then made about 72 pulls, trashing 3 clutch rods on the coast down, and only finding about 2 more horsepower with multiple intake, exhaust, tappet radius, jetting, and timing changes, so I must be close to the limit for this motor. I did find that the previously maximum hp rpm of 6900 could be increased by simply revving the motor to 7300 or 7400 rpm. So I added one more tooth for the Bonneville run.
The first day of racing at the BMST I spent helping my friend Doug with his Buell Blast powered 650 APG which has been a bear to get to run without a huge flat spot. We improved his run for Monday by 15mph so we were headed in the right direction, but after a 3rd change, the bike twisted on his towing trailer which is only about 3 feet wide, flipped over and broke his handlebar clip-on as well as the mounting bracket, and flattened one of the trailer tires and bent the wheel. So it was the end of the meet for Doug. To add insult to injury, he broke a brake line on his truck when he was leaving and could not find a replacement in Wendover, so is coming home with one brake line pinched off. It's a 10 hour drive in the best of conditions, so it will be a long trip for him.
So on Monday morning, I got my first run on the newly geared Beeza. 144 mph with a detour at the 5-1/2 mile mark around the left side of the kilometer timing lights, off the throttle, back onto the track in time to catch the mile timing lights. I may be the only competitor to have a "mile" speed with no "kilometer" speed. The track was rough enough that when I hit a series of bumps or a soft spot, I lost all vision with my riding position and no rear suspension. The motor was spinning like a top, so needless to say I was a bit disappointed with my attempt at making the straight line into a slalom course! I'm pretty sure I had to be topping 150 to have that 144 average even with the detour. Tom Mellor told me he had the same experience on his bike at nearly the same spot, so I felt somewhat vindicated.
I lined up on Tuesday morning after the riders' meeting, but ended up 16th in line just behind Bo (Wobbly Walrus), so got relegated to the 2nd queue. By 11:30 I had not moved and inch, and realizing that even after I would get to the line, there would be two other starting points to run before me, so probably a couple more hours, I got very discouraged. Then I thought about the course which probably had not gotten any smoother and decided that risking another off-track adventure could be dangerous so I packed up my gear and came home yesterday. After speaking to Bo about his run with full suspension, it reinforced my decision to back out.
As soon as I got the bike on the lift this morning, the wheels in my head started turning. I will be adding rear suspension, as we may well have to live with poor salt conditions in the future.
Tom