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Camshaft Development
| Description | : | Half of the time with a job like this, you stare at numbers and think. What I had been thinking for a long time was that the popular 174x8 cam was getting a little out of date. Too much duration! Yes, it works fine for most people but I wanted something better. Modern camshaft tech is all about using shorter duration. I placed a bunch of phone calls to the fine people at Megacycle (Jim and Barb are fountains of information) and we came up with a plan. What I had in mind was a little goofy, but it was worth a shot. I chose an available exhaust profile to use on the intake side, that had significantly less duration than the x8, and a little less lift too. I would have like to had the same lift, but without designing an entirely new set of profiles, ($$$) I had to use what was already available. On the exhaust side, I chose a HRC exhaust profile from a RS750 dirt tracker. Again, less duration and a little less lift than the x8. The cam was made, bolted in, and the results shown. (red line) More midrange, just what I wanted. (don't pay attention to the peak numbers, because the chart went goofy at the very top) I traded about 1hp on top for about 5hp in the midrange, right where the bike would be accelerating off a corner. Obviously, you can't see the part-throttle benefits of this cam on a full-throttle dyno run, but let me tell you, the entire character of the engine changed, it was much "sweeter" and well-behaved. Although it doesn't look like much in chart form, I was pretty happy with the result. Now, to find some more top-end... |
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