THE ONE-OFF EX5 ADVENTURE
T HE Art of Speed 2017 show was a hotbed of classic and custom cars and bikes. There were shop-built, home-built and shed-built customs scattered throughout the cavernous hall.
There were also plenty of manufacturers present, from Ducati to Triumph, all with their own large booths featuring their latest and newest models.
Among them, there was a Boon Siew Honda display with a smattering of custom-built MSXes and EX5s. And there you would have found the bike I built, the EX5 Adventure.
Boon Siew Honda wanted a custom EX5 built barely three months before the show’s date. But they also wanted to see the concept beforehand. A hastily sketched drawing later, I was surprised they okayed the concept I sent in - an adventure-styled EX5. Most EX5s end up being built into street cubs, but I had built some before and felt that I needed to delve into a more radical and lessknown area.
The bike delivered to me was a brand-new, unregistered EX5 injection. The first area to be addressed was the chassis. The engine would be completely stock, bar the exhaust.
Strengthening the chassis was important as the Adventure was going to be an off-road capable bike and, therefore, should be able to jump small hills in a single bound.
The original single-tube backbone was augmented with an additional tube and the steering head was boxed in to further strengthen the area. The box also doubles up as an airbox-cumsnorkel, which allows the Adventure to ford deep streams up to three feet deep.
The engine modifications were restricted to a freer-flowing exhaust, modelled on the Honda S90 Trail, an upswept high-level chrome pipe that matches the snorkels’ height.
Further modifications involved the front and rear suspension. Rear suspension is by longer and stiffer shock absorbers, a simple and easy way to increase ground clearance, necessary on an off-road capable bike.
The front suspension was more involved. It was not possible to increase the travel on the standard forks without compromising strength, so a pair of forks from a Honda MBX 80 was sourced. The steering stems were swapped over, which are easier written down than done. This allows standard Honda EX5 steering head bearings to be utilised without compromising on safety.
To add more ground clearance and to make the Adventure friendly offroad, the wheels were changed to a 19inch and 18-inch set front and rear. The stock front brake drum was chucked into the bin and an original Honda Wave front hub with a matching disc was laced onto the 19-inch rim. The front brake system came from the MBX 80, which meant the brake ratios were spot-on. The rear drum was retained. Both brakes and gear levers were equipped with shrub-cutters, which helped prevent foliage from interfering with the bikes’ controls. The handlebar needed to be changed to a high-level braced type to ensure the riding position is perfect for standing up on the pegs.
The bodywork required more thought than feasible. The side shrouds (not apparent on my presented sketch) were deemed to be important to be able to identify the bike as an EX5. Two sets were cut up before I was satisfied with the shape.
The front mudguard is a UFO supermotard item. The rear is an aftermarket off-the-shelf item. The seat needed to be cut, remade and reshaped to appear more “enduro” but is otherwise a stock EX5 seat. A rack was added to the rear to add more utility to the Adventure.
There was no mistaking the Adventure for anything else but a Honda because the colours I chose were traditional Honda racing colours. And the front headlamp and visor treatment even fooled Boon Siew Honda chief executive officer Nobuhide Nagata, who thought it was a Honda CRF Rally. Higher praise I have not found. Thank you, Nagata-San.
The Honda EX5 Adventure got many enquiries at the show. Many were asking the Honda staff on hand when Honda was going to build it, not knowing it was a one-off custom.