Months ago, on a whim, I entered the SFRC 6-hour endurance race which is taking place this weekend. I didn't know much more than it was 6 hours and on a go kart track. That sounded like the perfect way to come out of retirement and get back to racing in a low pressure, fun and slow way.
About two or three weeks ago I pulled my Honda XR100 out and gave it a quick kick and she started right up after a year of sitting. Great! I'm almost ready I thought. I signed up for a practice day at the track in McMinnville and wore my dirt riding gear as it was a warm day. It turns out the track is actually not very small and it's pretty darn quick. My little bike seemed like bringing a butter knife to a gun fight. I needed to fix some things.
The thing about the XR100 is that every racer has one. Kenny Roberts popularized the bike as the greatest way to learn to slide a motorcycle. It's small, it makes about 10hp, and it's unintimidating so you aren't afraid to push it around and learn where the limit of traction is. I've done many racing schools around the country and hands down the
American Supercamp was the one that taught me the most. The skills I learned there transferred to my TZ250, sliding tires at 100mph on pavement and made me a better, faster rider and I learned all of it on a diminutive little XR100.
Fast forward to my racing days and all my teammates and friends had XR's and our friendly competitive nature meant we all put work into our bikes to make them faster, better, etc. Mine was, as you might imagine, pretty tricked out.
So while I have a 120cc kit, a pipe and CR85 forks along with the de ri·gueur 17" wheels my brakes were woefully inadequate for this small track with a fast straight. Since we are going to get killed on power we're going to need to make up for it in corner speed and on the brakes.
I went to the local salvage yard and found a disk off a Triumph 955 that was 320mm or almost twice the size of the disc that was on it. A little machining got it onto the hub.
I started by putting the caliper from a CR250 on the rotor and holding it in position with the brake lever and a zip tie. From there I measured the various points and drew it on a paper and then, when it was close, onto some plywood.
Then when that fit I transferred the holes to a block of aluminum and marked it in blue and mounted to the rotary table.
And in only a day and a half later I got this:
It was some of the most tedious machining I've ever done but I had everything I needed to do it. The dream of the shop came through for me and I'm building a bike in my garage and to a high standard.
Then my lathe blows up.
I needed a crane to get away from the wall, the shop is a mess and it took a while to figure out the VFD blew up. I'm guessing chips from the mill found their way into the VFD and shorted it out. I was able to find a replacement and I made a chip guard but I lost a day. The good news is that I got so frustrated with the crowded shop that I sold a dirt bike and put some stuff in storage and generally cleaned up. That's a win.
In a vain attempt to find another 1-2hp I fitted a flat slide carb and ditched the airbox.
The rules for this race aren't casual either - the bikes have to be race prepped in a very serious way with everything drilled, wired and sliders all over the bike. It's turned out to be a crazy amount of work. I also needed a catch tank and decided that since I have the ability I would just make one.
My aluminum welding is getting much better.
In addition to the 6-hour race this Sunday (
http://sang-froidridingclub.com) I also committed to letting a friend race my KTM AWD at this Saturday's Dirt Quake (
http://sideburnmag.blogspot.com/2016/04/dirt-quake-usa-2016.html) and it will run in the "Inappropriate Road Bike" class where I'm hopeful that it will win. That was another few days of work as the fuel pump blew up a few months back and I hadn't addressed it. So this has been a very busy week of work in the shop but the best part is that the shop is complete and functional, if not a bit crowded.
If you're free this weekend I'd encourage you to get out to one of the events as they'll both be lots of fun. Everyone is welcome and if you show up for the endurance race you'll automatically become our pit crew - since we don't have one. Practice for the endurance race is Saturday morning, the KTM races Saturday night in Castle Rock and then Sunday is the 6-hour race so it's a busy weekend for me.
Okay, I'm not nearly done with the XR100 but I'll let you know how it goes.
Gregor