I wasn’t going to do this, but then this happened:
Dean,
Can you please email me or post a larger picture of your scooter as I have not seen it in person and it looks rather unique. email was PM'd to you.
When John Noonan, god of LSR racing asks, well what the heck!
So way back when, I raced karts. Several that I had looked like this:
And in 1971 a buddy and I decided to build a mini-bike and take it to Bonneville.
Set two records.
Then life intervened, and a whole bunch of years later, I started thinking about it again, and looked at all of the records, and thought a streamliner would be cool. I did some research, did a bunch of preliminary drawings, and realized it was way more work than I wanted to bite off.
So I started thinking about Special Construction with a blank sheet of paper. Since motorcycle aero is really terrible, I started by lying down flat on the ground and had my son take some measurements. I looked at head forward and feet forward and felt more comfortable feet forward.
Decided on a Yamaha TZ250 for power. Relatively easy to get parts, lots of power. V-twin two-stroke, 80 hp from Yamaha. I haven’t had it on the dyno, but there may be wee bit more power in this package.
The frame decision turned out to be a mistake, but more on that later. Early stages looked like this.
The wheels are from a 1985 Yamaha FZ250 Phazer, thank you Johnson & Woods motorcycle salvage.
I drove a Kart with a Kawasaki 350 A7R that went 172 with no suspension on some pretty bumpy tracks, so I decided that I would go rigid with this. The frame was designed to be rigid in torsion, but flex when loaded. Really tough not to have flex with a 10 foot span between axles.
The expansion chambers are adjustable. I used them on Karts and they broaden the power band significantly.
I have never been a fan of fixed-jet-bowl carbs. These are Tillotson Kart carburetors. The adjustable needle is attached to a servo. Haven’t worked out the bugs in it yet.
The radiator was designed to be too big, and it has caused problems getting enough heat into the engine. There is bodywork in the mold stage that was the reason for picking a large radiator.
The bar hanging out the back morphed into a roller stand. Found out the hard way there is absolutely no place to pick it up. Only dropped it once!
The steering might require an explanation. I didn’t want forks because of the aero. Center hub went through several design phases, but required a custom wheel, and that was more than I wanted to take on. Wasn’t against it, just thought I’d explore alternatives. When you roll through all of the ways to pivot something, and that’s all it is . . . a pivot.
A standard V-groove track roller on a curved track.
The rollers bolt to the frame on these brackets. The rollers have an eccentric so that you can set preload. Two press against one side, one against the other side. Very conventional rake and trail.
Overflow can
Driver after sampling overflow
This was November of 2006. I of course, thought it would be done for the June El Mirage race, but you know what a laugher that always turns out to be.
It turned out to be a short test session, one of several short sessions that followed. Blew the radiator hose off twice.
Ah, it was so clean. The hose is at the top. The stub on the head was designed for a really thin hose on the TZ250 race bike. That hose wouldn’t fit on this, so I bought a hose that would do the job. It would except with that really short stub it allowed the hose to crawl out from under the clamp. The first time I knew it was tight, but thought just maybe I might have missed it. The second time it was super tight. Ended up welding decent stubs on the heads. There was a long list of other things and that ended the November attempt. The manual shifter just wasn’t going to work.
The November attempt left a long list of things off the bike, so back to work. May is a long way off, no sweat! Yeah, right. Life always gets in the way of the fun stuff! Like trying to stay married. I know, over rated, but kinda handy.
Went out for a test run before the May El Mirage race and had nothing but problems. Wouldn’t shift for one. Managed about 40 mph and called it quits.
Went out in June the week before the race. Winds were blowing 30 mph when we got there and only got worse. The only reason we unloaded was the wind was straight down the lake bed. Broke the shifter on the first shift and while trying to fix it, broke an ignition wire. That was because we were being blown all over the place just standing there trying to work on it. Gave up, loaded up, got lost on the lake bed when the wind got over 50 mph and everything disappeared. Took 20 minutes to feel my way off to the exit road that was only a 1/4 mile away. Gotta love that place!
Ended up making the June race part of the test program. Ran 95 on the first run with very delayed shifts. Since the first test I installed an air shifter. The cylinder was just too small. Ran the second round about the same way with the same results. I left it way rich because I knew it was a test run and just wanted to get down the track. Managed to get only to 4th gear.
A bigger shift cylinder and a couple of other additions, and on to the July race. Leaned it out a bit, still not used to the shifter and ran through in 4th at a 104. The second run was looking much better and peaked at 110 in 3rd when the plug fouled. Or at least I thought it did. Getting ready for the September race I charged the small 12v battery and on Friday flipped on the switch to check things out. Nothing. Turned out I wasn’t charging the battery at all, and the fouled plug turned out to be a dead battery. Live and learn.
Made some more changes for September, put the pipes full in, leaned it where it should be and expected about 15 percent more power and figured it should pull better and not bog on the shifts. Wrong. It had about 50 percent more power and when I hammered it off the line it spun the wheel big time and went sideways. I recovered and dialed it again and spun the tire again. By this time my head is about way behind me instead of down the track where it should be. Went through the lights in 3rd gear at 105.
It was enough of an experience that I decided to skip the second run. Then I went home and cut the frame into pieces. But there’s an explanation.
When I took it through tech inspection the first time, Tom Evans didn’t like the flex in the frame. I countered that every Top Fuel chassis flexes like that. The decision was made to let it run. In July Tom and Russ decided that it had to be stiffer. I added two frame tubes, and it was stiffer, but still flexed a lot. Russ said in September that it had to be a lot stiffer and I asked him for a better definition, and basically he said it had to be stiff. No complaints, but the tubing design didn’t lend itself to doing that. It would have taken a truss to make it stiff, and it just wasn’t in the cards. Thanks again to Kent for offering to help weld a truss to it.
On to plan B! Damn I'm having fun!!!!!!!!
