Hi Guys,
I'm still not happy with my clutch actuation ... the cheapy 12v electric scissor jack motor and gear worked, but was too slow - about 4 second to fully lock up, but another 16 seconds to release completely. I think it would have been ok for this year, but I wanted a faster acting solution. Simpler would be good too.
I started pricing up a pneumatic actuator, which can be pretty powerful and quick when needed (disengaging the clutch) and slow when needed (engaging the clutch to take off at the start line). A single acting cylinder (clutch spring pushes it back) 63mm piston and 40mm stroke with a 3 port controller, some fittings and using the frame tubes as the reservoir crept up ober $1,000 pretty quickly. In past experience when it gets that high that fast I can expect it to go quite a bit higher before I'm done.
The problem with the simple lever that I used in 2019 was that it was long, real long. 380mm from the pivot (37mm the other way for a roughly 10:1 lever ratio). And I still had to give it a solid push ... 43kg worth it turns out.
It also meant I had only one foot on the ground at take off, which wasn't ideal .. and it hung pretty low when I had it in while moving (wouldn't really want to turn left). Now, the fairing was in the way too.
The problem with mechanical levers is that to get less force at the input end you need them to be long ... in other words, the less force you want to input for a given output required the more you have to move at the input end. And moving gets in the way of everything. The solution popped into my head while washing my hands (two times through the happy-birthday song certainly gives you time to daydream). What about a ratchet? Then, what about a jack? I get the force I need and multiple pumps breaks down the distance moved into small bits that add up to a big bit.
At first I priced up converting a motorcycle master cylinder (rear one off a GSX-R1000 I had) into a jack ...$300 of -3AN fittings later I remembered a mate left his shitty trolley jack at my places years ago. I've used it maybe 3 times in 5 years ... 2 of those times one of the front wheels fell off. But it has a little ram ...
And fit in the space really well ... and worked! About 7 pumps on the little stump where the lever plugs in and the clutch was disengaged.
But then it occured to me that maybe I could just remove the ram, weld a hose fitting on the end of his jack, and turn it into a big master cylinder. It looks like I can...
Weld on AN fittings only go down to -4 in the Rocket Industries catalogue I have ... but I just found a M10x1.25 nut in my stash of random nuts and bolts, so I'll weld that to a plate and then to the end cap, fit a standard M10 banjo bolt and see how it goes
Apart from finding out that racing is off until next near it's been a cracker of a day!
Cheers!
(p.s. I'll use a normal cable clutch lever mounted on the handlebar to do the pumping up and have another lever/cable to turn the release valve on the body of the jack to engage the clutch)