Saturday, March 3, 2007

When Shovelheads Ruled the World, Part 5

Three races; three class wins and two national records. Not a bad start for a couple guys who only started out to go to one race to see how they measured up. So why would they be thinking about making their bike faster? I guess that just comes down to the basic reason anyone is involved in any kind of racing.

With only the National Finals left in the season, I suppose it was only natural for Bobby and I to try something to go really fast at the last race. Bobby was the ideal partner in this respect. No sooner had we discussed the possibility of more modifications, than he was on the phone researching it.

I am not sure who he called first, but I suspect it was Jim Leineweber. He gave us some specs for distance between the valves while they were on their seats to see which of his larger cams would fit. Jim was probably also the one who suggested higher compression pistons. Lacing up a wider rim to spread the rear tire out and get more rubber on the pavement we figured out ourselves.

A call to Axtell Sales down in Des Moines got us a set of higher compression pistons for the Shovelhead stroker. I wish I could remember with any certainty what compression ratio they where supposed to be. They may have been 12:1. That doesn't sound quite so radical in today's world of efficient combustion chambers, but at a time when the most common modification to a Shovelhead was to put in low compression pistons (7.2:1) it was enough to really get your blood pumping just thinking about it! And beautifully machined forged pistons they were. You could almost feel the horsepower just holding them in your hands!

The cam that we settled on was a Leineweber L5. More lift, more duration, even more power! This was a much more serious race for us than the previous ones had been, so once the parts were in, Bobby sacrificed a couple weeks of riding on the street so that I could get his motor ready.

But first, I tackled lacing the new wider aluminum rim to the rear hub of the drag bike. Again , Bobby had come through by calling around until he found a suitable rim. A wide 18" rim was almost unknown in the Harley world back then, at least in our little corner of the universe. Normally a simple job, lacing this rim was a little more challenging since it came with 40 dimples, but no spoke holes drilled. Nothing my handy Black and Decker 3/8 inch electric drill couldn't handle though; that and a good eyeball that is.

With a week to go before we left for the finals in North Carolina, I got the bike finished. The motor was out of Bobby's Low Rider, new cam and high compression pistons installed, and back into the rigid frame. I think in was a Friday evening when I had it ready to fire up. I pushed it out of my garage, and fired it up.

By the next Friday night we planned to be on the east coast ready to race, so I didn't see any point in babying the new parts. I revved the motor....maybe even a little more than my judgement told me I should. The engine sounded strong, but almost immediately it came to a sudden grinding halt. What had I done?!? I felt like someone had punched me in the stomach. Obviously something had gone terribly wrong. Was it from my over revving? Had I made a mistake when I assembled the motor? What now?

So off came the heads again. The valves in one head were a mess; one broken off and the other bent and folded over; the piston far beyond salvage. All of the damage was in one cylinder, but it sure didn't look as if we would be going to the finals!

As I took the engine apart, it became clear that the initial source of the damage was not the valves hitting the piston, or even the valves hitting each other. To this day I am not exactly sure what the cause was. If I had not revved the motor so high, would that have just delayed the "incident" until Bobby was on the strip?

My first instinct was to throw in the towel, but after talking it over with Bobby we decided to at least see if it might be possible to fix the motor in time. Our Matco Tools dealer, who had helped us out with some cash before the Iowa race in exchange for putting his sticker on the bike, offered to pay for a new piston if we wanted to try to fix it in time for the finals. That was enough to seal the deal. We got another piston coming, a couple of valves, and found someone who was willing to replace the damaged valve seat for us on short notice.

Time was running out, but it looked as though it might all come together for us. As soon as I got the head back from having the new seat installed, I did a standard 3 angle valve job on it. In retrospect, I hate to think how much flow we lost from that, but hey, sometimes ignorance is bliss!

Our original plan was to leave right after work on Thursday night, but now I would be re-assembling the top end right after work. The modified plan was to be loaded up and to leave from our house as soon as the bike was ready. I decided that it would be best to actually hear the engine run before we loaded it up, just in case I had neglected something. The last thing I wanted to do was to get to the east coast and find I had left a critical part in my garage in Minnesota.

As the clock neared midnight, I tightened the last few bolts, and a couple of kicks later the engine was running. We probably didn't let it run for more than 10 seconds before I shut if off and we loadeded the bike up. Against all odds we were on our way to the HDRA National Finals in Farmington North Carolina!

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