DragBikeMike
Serious Thumper
Offline
SuzukiSavage.com Rocks!
Posts: 4071
Honolulu
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How does it run?
Street manners are pretty good. It starts right up. I think it starts better. Initially, I thought the fuel mileage was way off, but after living with it for a while I really don’t see much of an increase in fuel consumption. Throttle response is good, and low speed torque is just fine. The low speed torque seems a little less than what I had with the stock DR cam but still ample. It has excellent low speed performance. On the freeway, it has superb acceleration. Screw it on at 70 mph and acceleration is brisk, a real arm stretcher. Very easy to merge or to pass a big rig. That also holds true for country two-lane roads. You can get around slower vehicles with confidence. I evaluate my performance mods using a GoPro camera and stopwatch. I record my 2nd gear 4K to 7K time and then review the video with stopwatch in hand. Prior to installing the 340b cam, my 4K to 7K time was right at 2.90 seconds. With the 340b, the 4K to 7K is slightly slower, about 2.95 seconds. But the power band is now extended all the way to 8K. I haven’t tried taking it past 8K, that’s the limit on my tach.
Comparing the 5K to 7.5K times shows the 340b is slightly faster at 2.88 seconds vs 2.95 seconds for the stock DR cam. That makes sense. So, with the cam retarded 5° from the factory marks, and no other tuning, it pretty much runs with the stock DR650 cam up to 7K, and then continues to pull strong past 7K all the way to 8K. I’m using 92 octane pump gas with no octane booster. I haven’t tried any jetting or ignition timing changes.
It runs well, but to be honest I anticipated a big bump in steam. I suspect that the 4K to 7K time would improve somewhat if I advanced the cam timing back to the factory marks. That will close the intake valve sooner and increase my cranking pressure. It might put me back on the octane booster. I plan to try it to see what happens.
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