Zero electric motorcycle

Charging at Tsawwassen Mills with a J1772 adapter

Various Links

The lefthand brake saga

I sometimes take my motorcycle aboard my sailboat (see e.g. 2008 vacation), which involves taking it up and down a ramp. I also occasionally transport it in a pickup truck.
The technique is to walk alongside the bike to provide stability with 3 points of contact (twho wheels plus one foot on the ground), given that the boat may be moving. To get the bike up, I drive it up with the engine. To get it down, I back it down with the engine off, in first gear, using the front brake (acting on the front wheel) and clutch (acting on the rear wheel) to control the descent. Since the bike is on a slope, most of the weight (and hence most of the stopping force) is on the rear wheel.
Problem is, the Zero has no clutch, and the electric motor provides no braking whatsoever at zero speed. Using the front brake alone, the tire slips.

After some discussion on forums, asking Zero support, and talking to a couple of mechanics, I decided to fit a left-hand brake acting on the rear wheel. Zero in fact makes a parking brake as an option, but it's expensive and as far as I can tell it's a lock, not a normal brake.
I could not just use a right-hand assembly upside-down, because the hydraulic cylinder is integral to the lever assembly and would be the wrong way up. Initially I ordered a left-hand hydraulic clutch assembly from banggood on the advice of a Ducati mechanic (at least, he suggested I look on banggood but did not recommend a specific item). That turned out to have too small a reservoir; probably intended for a smaller bike. On returning to a local bike store, which had initially been unable to help, the owner found an assembly somewhere on a shelf that did fit and had a good size of reservoir. I fitted that on the handlebar, with the brake hose feeding the ABS controller in place of the foot pedal hose. I was able to bleed the hose out through the reservoir, and the system worked quite well - I had two hand brakes to back the bike down a ramp.

Then I realized that I did, in fact, occasionally want to use the foot pedal - when stopped to use my phone or GPS. So I thought I would combine the two, with a dual banjo bolt. Having stolen the original rear brake hose to connect the left-hand lever, I had another hose made up with the requisite fittings. Bleeding the system did not go well - I realized that the upper cylinder was leaking out through the lower cylinder hose.
I only needed one reservoir, so I decided to block the connection to the original lower one. I did that with epoxy and a steel washer, blocking off the channel from the brake cylinder. I still had not fully understood what was going on in the brake system. I managed to bleed out the system successfully, and the hand lever worked OK, but if I used the foot brake, the system leaked into the upper reservoir. There is a small channel connecting the reservoir to the cylinder, which is open when the brake is not engaged, but is closed by the piston when the brake is operated. This makes the system self-bleeding - air bubbles rise to the top and out into the reservoir when the brake is not used - but means that my simple connection could not work. When I looked online again I found references to a non-return valve that might work, or systems that used two sets of calipers. In the event, I secured the hand lever in a half-depressed position with wire, closing the channel, so that I can use the foot pedal when stopped. To use the the hand lever for backing down a ramp, or when riding, I have to pump the brake a bit before it works to the full extent. Overall, it's "good enough".

To solve the problem of having no parking brake (cannot put the motor "in gear"), I made a sprag from a length of steel rod. If I insert that through the rear forks between the wheel spokes, it stops the wheel turning.

Andrew Daviel