Monday, December 2, 2013

Is it summer yet?

See you at High Plains Raceway in 2014!

28 December: Got to ride it at HPR during their "Customer Appreciation Day" today - everything went very well! Only ran about 13 laps, but it was enough to get more experience and reveal what I need to work on next time out. Smoother corner entrances resulted in higher cornering speeds, less panic, and earlier drives out. I also discovered that this bike, like any other, responds well to body positioning (And poorly to bad positioning, such as leaning the shoulders the wrong way to keep my head level when cranked over), but this one doesn't need nearly as much gymnastics to make the handling more neutral while cornering. When your butt is just over a foot off the ground, the idea of getting it even closer (Especially to the curbing!) seems just wrong at first, but the way it improves the handling inspires loads more confidence. The speeds are up to the mid '90's between turns 3 and 4; when you're that close to the ground, the sensation of speed feels absolutely insane. But as exciting as that has been so far, that speed is still too slow and uncompetitive for a 500 twin. The good news is that we'll go a lot faster with higher turn 3 exit speeds and later braking before turn 4. So far, I've been braking way too early for, well, all the turns, but that'll change!
Sorry, no lap times and no video, yet.


Saturday, April 13, 2013

Crunch time!

The Dynojet kit #2728 (EX500 "Stage 7") I installed two days ago worked great (The Keihin CR33s are on backorder). In spite of anonymous EX500 forum guru warnings against it, that jet kit completely fixed the flat spots and throttle control issues I had 2 weeks ago. The complete kit was installed as instructed, but with #136 jets and needle clips one notch above center (That works at 5100 ft elevation). The CR Specials will still get installed to sharpen the throttle response some more, but the original CV units now work amazingly well. A foam headrest on the rear shock reservoir solved the neck strain problem.

Drove out to HPR for the MRA racing school this morning. The bike sailed through tech. I thought the first hour on the track went fairly well. Then my instructor suggested some really good changes to my lines and turn-in technique. The bike is extremely easy to flick into a turn, which makes it all too tempting to turn in far later than normal, late apex it, then drive out without needing the whole track. Great fun, and feels safer than it is since I felt like I was never in danger of running out of track at the exit. The real danger comes from lowsiding while flicking it in stupid late, which hadn't happened to me, yet. Next time out, I was rather happy with the much smoother way I entered/apexed/exited turn 4, only to not stay focused and completely blow my entry point point at turn 5. I tried to tighten my line and dive harder towards the apex, only to lowside hard onto our left side. We slid to the outside of the corner, hit the dirt, then rolled over onto our right side and slid some more. I got a jolly good beating, felt really stupid, but have no broken bones, abrasions, dislocations, or any other of motorcycle racing's occupational hazards.

The bike is quite repairable. The worst of the damage is a split gas tank inside the nose section. Fabricating the unit fairing/gas tank seemed like the path to simplicity in maintenance and lightness, but it made crash damage vastly more complicated. And it was a real pain to make in the first place. Not to mention the thrill of wearing a full tank of gas while stuck under the bike with a hot engine! The handlebars are bent, which are cheap and easy to make. The hard plastic footpegs (Originally sold as BMX grind pegs!) saved both me and the bike from a lot more damage. Then there is the dirt - it gets everywhere when crashing off the track. The frame got rashed, but that's fixable. The exhaust will need a little hammer time and paint. My helmet never got a scratch, my gloves and boots are still good (And match my leathers better now), and my leathers only need a small patch on the arm, maybe.

A surprising number of racers asked if I'd have it ready for the first 2013 race on 11/12 May, which was very encouraging. If I focus on getting it trackworthy and get my race certificate, well, it could happen before the end of this racing season. My other option is to take the bike down, leave it on the bench for at least another year, and get the new rear suspension done. That suspension system should help the cornering a lot by making the bike even more flickable while making front end slides far easier to control and reducing lean angle. But time at the track should provide some badly needed experience. While I enjoy spending time working on the bike in the shed, good results are only going to happen after I spend a lot more time on the track. Decisions...

25 April: The van blew both the transmission and the year's racing budget. 2013's racing season is over. Lots of prep time available for 2014...


Thursday, April 4, 2013

Track time!

We got the opportunity to test the racer at High Plains Raceway on March 30th. It handled extremely well! No chassis or suspension adjustments were required. It has lots of steering feel. It is dead stable yet very responsive. I had absolutely no problem either maintaining or changing a line.

Only 7 laps were done. Poor carburetion made the engine very difficult to control. And neck strain made life at higher speeds very difficult. A Keihin CR33 carburetor kit is on the way to fix the former. A headrest will fix the latter.

While we went a lot faster and cornered a lot harder than I expected the first time out, we still have a long way to go towards generating respectable lap times. But I'm approaching the next time out with a lot more confidence. Is the development of a new racing motorcycle concept with unproven geometry on a racetrack by a 50 year old novice racer a good idea? Can't think of many other things I'd rather do.

That's my wife, Suzi, sitting in the Battlewagon. I'm thrilled to have her company at the track. And Suzi's thrilled when she doesn't have to drive me back from the track.

The next track date: MRA racing school, April 13th (April 21st, in case of bad weather).

Monday, December 10, 2012

Done and running!

And we are finally ready for some track time!

Frequently Given Answers:
  • The race number has no deep meaning - it was just an available number.
  • The exhaust exits out the side, not to the rear - there are no "flaming butt" issues.
  • The steering axis is not parallel with the front fork - there's a virtual pivot at the hub.
  • The EX500 engine is internally stock.
  • The rear swingarm, vertical link, and drum brake are temporary - a more advanced system will be installed later.
  • NO street conversion or version is planned. Ever.
  • NO (Fill in the blank movie) replica bodwork is planned. Ever.
  • The bodywork could be a lot more aerodynamic, but finished bodywork (And/or any other component) beats unfinished bodywork every time.  
  • 4 years construction time in a garden shed at a budget of under $1.00/day.
  • The donor bike cost $500.00 - the leftovers were sold for $600.00.
  • Having a full time job not even remotely related to the motorsport industry, younger and older children, internet connection, lack of money, etc... didn't stop this from getting built.
  • Work has started on the replacement rear suspension.
  • No, I'm not giving away any design or building advice. Nor am I asking for any.
  • 414 pounds ready to ride except fuel, 50/50 weight distribution with fuel and 150 pound rider. 74 inch wheelbase. Just over 4 inches of trail.


Friday, October 22, 2010

A few years & a few thoughts later...

There are good reasons why there haven't been any real updates for a long time now. The main reason is that the racer is not done - yet - but there has been steady progress, even if it has been at a glacial rate. The other reason is that the likelyhood of any project's completion is inversely proportional to how much time is wasted blogging about it.

The project started as 3 big design steps forward early 2008. Actually finishing it meant that 2 steps have been taken back. It was completely redesigned late 2008. The second step forward (Two wheel steering) will be fabricated and installed after the racer is done, tested, and well used. The third design step (Two wheel drive) will wait for another project.

Even if the machine is capable of amazing lap times, well, I still need to learn a LOT about generating amazing lap times. Living in an area with a fantastic roadracing club (MRA) and an amazing new track an hour away (High Plains Raceway) is a real blessing.

So just how great can an EX500 powered racer with a heavy steel frame and stock wheels really be? Well, as much as it excites me, you won't see "The Making Of..." artsy video nonsense or any other pompous promotional puffery. But it will provide loads of valuable information and experience for very little money that will be applied to a far more radical, faster, and better finished racer.

Oh yes - the racer project is, as the homebuilt aircraft people like to say, "90% done, 90% left to do"...

Monday, August 4, 2008

The Very Advanced Racer Project

Over the last year, I've been buying, measuring, and otherwise staring at a growing pile of components, tooling, and materials required to make a motorcycle. I'm past the bulk of the "Enter your credit card number" phase. Now it is in the "Turn lots of little parts into one big part" phase. What it is going to be:
  • A track bike. And if it performs as well as I expect and the organizers don't object, a racer. There are NO plans for operating it on the street or for making a street version.
  • Powered by an EX500 engine. It is a fairly compact, reliable, common, and cheap twin. It also had to be eligible for a "builder & budget friendly" racing class, which pretty much means twins or singles. A Supermono was considered first, but the good engines cost more and produce less power than the light twins.
  • A proof of concept bike using many of the ideas seen below. My mental test rider loves it. The theory promises large performance gains. The low power experimental bikes performed very well. But stopwatches at the track with a real motorcycle will tell me if it really works. And after that happens, the opportunities for racing and further development with even higher performance engines will present themselves.
  • Very cheap. The budget for this entire project is less than a set of high end racing forks. If it weren't for the miracle of loose credit back in mid-2007, this project would still be in the hot air phase. There are no sponsors for this project - yet.
  • Done entirely by: Me. That includes the design, machining, welding, and composite work. Nobody else's fingerprints are on it.

Wednesday, November 22, 2006

The 2WS/2WD experimental recumbent

In theory, a 2 wheel steering bike could enter and exit corners harder. Several years were spent designing a 2 wheel steering "kneeler" type bike until I saw a Ryan recumbent bike sitting in a bicycle shop in 1998. That struck me as the perfect configuration for a 2 wheel steering racer. But rather than spend a lot of money building a high powered one with no prior art available to depend on, I built a lightweight electric one to test 2 wheel steering stability and control. It has 3 12v batteries, 2 800w Heinzmann hubs, and a Curtis 1204-001 speed controller. It was finished in early 2002. The steering has a 2 axis control - moving the stick left steers the front wheel right - which causes the bike to roll to the left - just like an airplane. The rear steering is proportional to the front - with the stick forwards, the rear steering angle was 50% of the front in the same direction - and with the stick aft, the rear steering angle was 50% of the front in the opposite direction. The proportion was completely variable with no rear steering at all when the stick is centered. The speed control and brake lever is also on the control stick. The second to last picture was taken at a recumbent bicycle rally in Arvada, CO, back in 2004. The bike is currently hanging from my living room ceiling after several hundred miles of successful testing.

The H-D powered sportbike project

This one was designed in 1987, initiated construction in 1988, and finished in early 1991. It was powered by a 1988 H-D Sportster engine. The wheels, frame, bodywork, etc. were fabricated at home. The front brake has an "inside out" rotor on the left side of the rim. The front end steered on an upper ball joint and 2 virtual pivot arms aft of the hub with an 18 degree steering angle and 4 inches of trail. The bike weighed 365 lbs. The wheelbase was 55 inches. It was dead stable at any speed and could be ridden no-handed from 100+ mph down to 10~mph with no wobbles at all. The bike was featured in the Oct '91 Motorcyclist, Jan '92 Hot Bike, and Summer '97 Battle2win magazine. About 4200 miles were on it when it was sold in '93 to build the Big Twin powered follow-up bike - which never got finished and the parts were sold.