Jeremy Webb’s Husqvarna E-conversion

March 14, 2020
4,077 Views

When I first saw this electric dirt-bike conversion, I was immediately impressed. It was made by a builder named Jeremy Webb who lives in Tasmania, a large island at the southern tip of Australia.

Tasmania, Australia

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The Donor

Jeremy found a 2017 Husqvarna FC250 at the right price, and the STEEL frame looked as though it would work well for the conversion he had in mind. Jeremy now regrets not taking more pictures of the process, but he didn’t think anyone would be interested in that (what!).

A 2017 Husqvarna FC250 frame

Here are the pics that he did have, and they are just enough to tell the story. The motor is fat enough that there was no way to mount it with the drive-sprocket located right where the stock transmission output normally was. Jeremy decided that as complex as it might be, the adding of a jackshaft between the motor and drive sprocket would actually end up being the easiest option.

The right-side primary reduction between the motor and the jackshaft, which passes under the motor.

One of the things that really knocked me out about Jeremy’s build is how professional every part it. It actually looks like a factory electric dirt-bike from Husky. In fact, if he told people it was a new prototype from Husky, I’m sure everyone he met would believe him.

28T : 13T provides a 2.1:1 reduction in RPM’s, and a 1:2 boost in wheel-torque.

The jackshaft bearings are off-the-shelf items, but the shaft itself is definitely a custom-machined item.

The custom jackshaft

The final drive is shown below, and the stock components from Husky worked well.

The stock Husky output sprocket using 13T

The stock final drive uses a 13T drive-sprocket, and a 54T wheel-sprocket for a ratio of 4.1:1…with a total drive-reduction of 2.15 X 4.15, the RPM’s between the motor and rear wheel is 8.92:1

A slim liquid-to-air radiator from a KTM 65cc

The motor that Jeremy selected is a DHX Hawk 40, which has the option of liquid-cooling. Jeremy found a radiator from a KTM-65 that fit very nicely into the “now unused” Husky air-filter housing, and he was able to use that option, which is a HUGE performance benefit.

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The Battery Pack

Of course, one of the FIRST things I most wanted to know about is the electrical system, and especially the battery. Jeremy took the same approach as the Zero electric motorcycle company. Zero motorcycles uses 28S (28 lithium cells in series), and when fully-charged to our recommended 4.1V per cell, that would be 114.8V (roughly 100V nominal).

He found a flat pouch cells with specs he liked, and he was able to fit six of them in parallel (6P). The pack was built by Chris Jones. There are three here, so Jeremy can swap them out, and he made the pack housing so swapping can be accomplished fast and easy. If you want to learn more about battery construction, click here for our article on that.

Three identical battery packs, 28S / 6P

There are no pics available of the controller, but it is a Sevcon Gen4 size-6 controller, which is used on some Zero E-motorcycles. He also uses the well-regarded Domino throttle.

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The weight distribution is 60kg rear and 56kg in the front (152-lb, 124-lb).

The finished result

“…My requirements for this build were to have a similar weight
distribution to the standard bike and an easy to swap ~3kWh pack so that
it could become a replacement for petrol powered bike at the small
local track…

…I chose the Husqvarna because of its steel frame, knowing that the
frame would require modification to fit the pack size I needed. It
also has good plastic coverage to hide the electrical and cooling
system.
..”

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Written by Ron/spinningmagnets, March 2020

Grew up in Los Angeles California, US Navy submarine mechanic from 1977-81/SanDiego. Hydraulic mechanic in the 1980's/Los Angeles. Heavy equipment operator in the 1990's/traveled to various locations. Dump truck driver in the 2000's/SW Utah. Currently a water plant operator since 2010/NW Kansas


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