Update 013
In the past couple of weeks I have been working on items from my list of what's needed to get ready for airfield testing. One important item is instrumentation, that is having an accurate working rev-counter and speedometer. As part of my work on these items I recently took the Honda to a rolling road that I use. The aims of the visit were to connect the tacho from the CBR600 clocks to the C90 motor and confirm the accuracy, and secondly to check the gearing and possibly power output.
Firstly the tacho connection, which proved to be a bigger problem than anticipated. The CBR600 tacho, in common with modern sportbikes, is designed to work from a positive (probably square wave) signal sent by the ECU. The C90, which never had a tacho, has only a “coil negative” signal available, which will suffice to drive an automotive multimeter but cannot drive the tacho. Although I could attach a multimeter for temporary testing purpose, I really want to use the CBR unit because it is integrated with the speedo. Although we found no solution that evening, I am just about to test a PNP transistor to convert the input signal – pushing the limits of my electronics knowledge.
The gearing/power check run proved even more disappointing. To hit my speed target of 100mph, the motor needs to run at 12000rpm, which means 6000rpm at 50mph, which is 80kph (the Bosch rolling road is calibrated in kmh). So I ran the bike up to third gear, watching the speed output on the control unit display and the rpm signal from the engine analzer, only to find it wouldn’t hit 80!
The engine had insufficient power to overcome the resistance of the rollers (which are meant to be “free rolling”) so measuring power was out of the question. A subsequent test in second gear proved that the engine revved to 8000 (could have done more but it seemed pointless) with reasonable AFR. The data we did collect confirmed that gearing should enable 100mph, but it looks like that will have to be done “on the road”
Here’s a shot of the test
For the record, this image also shows some other work that I completed
A) Alteration of steering mechanism from a traditional steel tube with clamps, to a fabricated aluminium control bar that is “bolted” and will house switch-gear and controls – also has improved stiffness and geometry.
B) Changed seat-back, now upgraded to Toyota MR2 item which is smaller, lighter and has recline angle control built in.
C) Exhaust silencer connected, unlike earlier test, the Apillia tip can keeps it suitably quiet for a “straight-through” style muffler.
Next step is airfield test – scheduled two weeks from now, then we’ll see if its gonna work.
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