Racers
Not on as tight a budget as when he was young, he built up his dream with Shell racing parts, a modern ignition and all the trick little items people have discovered over the years to help these Yamahas keep up with Harleys on the big mile and half-mile tracks. When the day came for him to fire the beast up, he kicked it over and went out to the street for a few quick sprints. He came back sweating and shaking. “I don’t know what I was thinking,” he said to himself, “I can’t possibly do that again.”
On our scales, the Yamaha weighs 303 pounds, down from the OEM weight of 428. It has about 50% more horsepower than it did when stock. The resulting power-to-weight ratio makes this 40-year-old dinosaur more than a little raw and exciting, even by today’s standards. After the abovementioned reality check, the Trackmaster ended up on eBay and the former racer found himself a nice stock XS650 that he dolled up with paint to look like this one. He now happily rides that street tracker all over the Dallas area.
I’m sure not giving the previous owner any grief about his decision not to race again. I know that I can’t get back out there, either —and I wouldn’t need the lap around the block to convince me.
So other than as a conversation piece, what am I doing with it? I’m kicking around the idea of building some kind of café racer/street tracker combination and imagine myself being able to wire this thing up and make it streetable. I sold Yamaha 650s in the late 1970s and am pretty knowledgeable about them. They seem to run forever. I remember one of the mechanics at Yamaha of El Paso had an XS650 that was ridden and ridden subjected to the usual benign neglect many line mechanics inflict upon their basic transportation. The bike’s speedo/odo unit would fail about every 20,000 miles; as I remember he went through four of them while working for us.
All wasn’t peaches and cream with these bikes, however. They shook like paint shakers. I rode one home one day at lunch and even after that short four-mile stint my hands were numbed out and felt like I was trying to palm watermelons. As I started looking into this project, vibration was the first problem I knew I’d have to overcome.
At about the same time I bought the bike, I ran into Kevin Duckworth of Loaded Gun Customs at a convention. We turned out to be kindred spirits. He was stuffing a Norton 850 into a Buell frame, had built a host of Yamaha 650s and was heavy into the vintage Triumph scene (see “Gun Show,” Barnett’s BikeCraft Magazine Fall 2012). Like me, he has nerve damage in his hands and vibration accentuates the issue. “How the hell do you ride Yamaha 650s if vibration bothers you?” I asked. His trick was to purchase sheets of carbon fiber and trace his motor mounts onto them, using its vibration-absorbing qualities to partially tame the vibes. I ride road bicycles and there is clearly a lot of difference between a steel or an aluminum frame and one made of carbon fiber in terms of comfort when hitting bumps. So, I’ll be sending my motor mounts to Kevin on this project.
Google-surfing also led to a potential fix. Online I learned about crank re-phasing for Yamaha 650s. The pistons on this parallel twin move together, firing alternatively 360-degrees apart. The mass is jumping up and down, both pistons coming to a stop at TDC and BDC each revolution. Some tuners are now pulling the crankshaft apart, rotating one cylinder’s flywheel assembly three splines and putting it back together. This results in the cylinders firing 277-degrees apart. Fussier types use a modified flywheel, set timing order at 270-degrees and weld the crank together. Now the pistons are not moving up and down in unison resulting in a motor that runs much more smoothly, has a little more torque and a much more interesting sound. It requires a different cam and a modified ignition, both of which are readily available.
Hopefully, I’ll stay on this project all the way to the end and report back on whether these two modifications work to make a nice ride out of this little racing monster, If not, at least I’ll have a good motor ready to pop into a stocker if that turns out to be a better choice.
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