Bazza, that works fine- the only problems would be keeping it lubricated. Blown back petrol will wash off anything we put on, and it's not exactly simple to access and re-grease on a regular basis.
So for now I'm looking at a simpler rotating cam operating from the side lifting an actuating bar on a parallelogram arrangement to keep it in line.
Another alternative is the worm drive form below, but there's less room for the motor there- I'm pulling my bike apart today to measure the clearances to see where that actuator might fit.
The advantage with option 1 will be quicker actuation- I want it to be able to react as quickly as the throttle is rev'd, if possible.
But all input welcome, and I might mock up your suggestion to see how it could be done, without leaving spiral slots cut in the side of the stack, through which air will leak. Maybe a double thickness wall, with spirals cut into the outer one only? But I'd rather keep the amount of clutter inside the box to an absolute minimum.
Xenocide wrote:
1) Can we just take the top off? Yes, we can- but the lower section will still need a good transition radius for the air to flow over. This will be even more critical if the air is primarily flowing in from the sides over the lip. Also headroom is critical, and we have to allow for the fact that some people have std Honda filters, others K+N or BMC. Going upwards is difficult without raising the airbox lid, which means raising the tank.
2) We do it via TPS... How does the VTR sense RPM for the speedo? Crank sensor? I should be able to figure out the speed of that and use that data too.... hmm. Very possible. I was trying to keep the sensor data needed to a bare minimum at first, even thought of actuating the lifting mechanism via a left-hand twistgrip to test whether it worked at all initially. I'm conscious that ideally we end up with a fairly simple "How-to" that anyone who wants to can copy. The more simple it can be made, the easier it will be to make and fit.]
I've played with an old abs sensor before and managed to get it to count the pulses and figure out a speed (wasn't calibrated) but it worked...
Also I was thinking, the TPS uses the bikes's power + ground then the computer figures out the throttle position by the difference between what's coming back off the wiper arm of the TPS and it's 12v+ line. Normally that wouldn't be a problem because you know what your input voltage is but with a bike it varies with the rpm of the motor (due to the stator - 12v-15v pretty much) so I'll need to find a way of passing the controller a reference voltage as we'll just be tapping into the TPS value rather than supplying our own known voltage. How about using a microswitch on the throttle cable pulley or connector bar instead?
Bloody complicated sometimes!
Olbikeman- Yes, I think that's what the restrictor ring made of aluminium set into the inlet rubbers is for, but it's very crude.
Trouble is, you need a small diameter port for low speed running and a larger one for higher engine speeds, and I've never seen a satisfactory solution for that one which doesn't interfere with smooth air flow and knock some of the vaporised/atomised fuel droplets out of the stream, which would make accurate fuelling a nightmare.
Actually the intake rubbers could do with being remade smoother all the way through- the variations in diameter and steps aren't helpful.
If it weren't for the fact that the carbs are at different angles a machined aluminium or hard plastic one would be better altogether, I think.
It's not falling off, it's an upgrade opportunity.
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mag or site.
