Ducati ST2 CAMS DIALLED
The first time Id had a chance to play with an ST2, and I was hoping for some good results. One of our salesmen had bought an ST2 when they were first released, and he had the guys at Dynobike ( very good friends of his ) set the cam timing on his bike. I dont know where the cams were set, but John said the bike was more responsive and nicer to ride afterward. So I was keen to try one myself.
For starters I took this bike to the dyno and gave it a base run. This bike had ARROW mufflers and a FIM chip. The curve that came out surprised me. The power goes flat at a bit over 7,000 RPM, then holds to 9,000 RPM. This struck me as rather odd, as the injected bikes should make power to at least 8,000 RPM. I had a look at some other ST2 curves and they were similar, so there must be something about the model that does this. Maybe the extra capacity overloads the ports, even with the short manifolds, similar to some theories about the carb engines. Or the small and long air inlets could be a problem. I guess the 78 Hp struck me as a little low for a 944 cc engine too. As I said to the owner though, I dont know if Ducati put some time into these heads or just got out the old 907 heads again. The early heads certainly werent great on the inlet side in particular.
Anyway, digressing again. I checked the standard cam settings on this bike and, surprisingly, they were very close to spec. I then checked the piston to valve clearance and decided on a setting centreline. Turned out to be pretty much the same as the SS setting. So we set it up and headed off back to the dyno.
Sometimes things dont always turn out as planned though, and this was one of those. The power increase was minor, and even the torque comparison only showed a pretty steady 2 ft-lb improvement across the range. Not much ( about 3% at the peak ). I finished the mapping so I could give the bike back to the owner as it should be and headed back to work.
When the man came in I told him the story and said ( as I usually do ) "if you dont like it, bring it back and Ill put it back to std". I have no problem putting things back to standard if the payer is not happy with the result, and a money back guarantee certainly makes people happy. The owner said hed try it for a couple of weeks and let me know. When he did, he said it was certainly more responsive, and more powerful through the mid range when on a good ride in the hills. The top end didnt feel much different, as expected, but he was very
happy with the overall result. He used the phrase "more get up and go" quite a bit. This made me happy, and proves once again that, although the dyno is a very valuable tool, it doesnt always give the whole story. The graph below shows before in green, after in red.
Dyno graph courtesy of DYNOBIKE (03) 9553 0018
Another thought I had for this bike was regarding the airbox lid. The inlet to the airbox on these bikes is not as good even as the SS or M models, so that has to be an issue. Sigma Performance found some good gains on an ST4 by just cutting part of the lid out, which also had the advantage of keeping the noise down. Our owner tried riding with the lid off at my suggestion to see if the extra noise would annoy him. It didnt, but the performance dropped off at the bottom end. This confirms to me that the lid is a real restriction and will certainly need more fuel to work properly. Back to the dyno again. Hopefully some more on this to follow.
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