CBR600F4i conversion: Stock to Stunter in 5 hours.

 

45 years ago, my great-uncle Athol jumped his ailing BSA over a barrel-and plank ramp and through a flaming hoop out the back of the Cobden pub for a carton of beer.  Stunt riding has evolved somewhat since those heady days, and while Athol’s long suffering Beezer was bone stock, today’s stunter generally makes some fairly significant mods before they’re happy with a motorcycle.

Modern stuntbikes with their specialist tackle tend to raise a few eyebrows parked outside coffeeshops, so when Nam Tran from Melbourne stunt crew Front Up Freestyle told me he’d just bought a pristine secondhand F4i and was about to tear it to bits in homage to the wheelie gods, I thought it was a process worth documenting.

So here it is - 5 hours’ work on a Sunday afternoon, $2 grand’s worth of sexy bits off the internet and one of Japan’s finest sportsbikes to be sacrificed.

12:00pm: Get naked

 

“Fairings are expensive,” says Nam as he pulls the plastics off the sides, tail section and front of the F4i, “This poor bike’s gonna spend a lot of time on its side.” Lights, dash, exhaust and ram air snorkels are all removed.

 

12:30pm: Barring up

 

Stoppies, in particular, benefit from wide, high and very solid handlebars. Not wanting to go for the full top triple clamp conversion (which he’d need if he wanted to put flat motocross ‘bars on the F4i), Nam’s chosen a set of two-piece clip-ons from Yanashiki, angled upwards for best leverage. The solid aluminium bars can be flipped and re-used in the sexy red clamps, or replaced when they get too badly damaged. As they’re not too much longer than stock clip-ons, no new hoses or lines are needed, and everything slips straight on.

12:45pm: Brace your rear

 

Two issues here - the FUF boys tend to pull stand-up wheelies while standing on their pillion pegs, which fold up, bend and in general don’t like being jumped and stomped on. Also, the exhaust and subframe tend to take a knock or two as the bike falls over. Killing two birds with one meaty subframe brace, Nam ditches the standard pillion pegs in favour of a Sick Innovations subframe cage, which gives additional sideways strength to the subframe and a bit of sideways exhaust protection, as well as huge, chunky, grippy rear footrests for stand-up tricks. It bolts on in minutes.

1:00pm: Cage match

 

“One thing I’ve found,” says Troy, another of the FUF crew, “is that the better you get, the more risks you take, and the more you fall over.” All the boys’ bikes wear some sort of crash cage, either bought or welded up from tubing in the backyard. A good cage not only protects the engine and frame from damage, but braces the engine mounts against some of the extraordinary forces stunt riding can put on a bike. This one, from Sick Innovations, is difficult to fit but very solid, bolting straight into the engine mounts and coming around underneath under tension for extra sideways impact protection. You can even mount oggy knobs into the sides of it.

1:30pm: Monster sprocket

 

While he’ll still ride it around town, Nam’s got no use for a 250kmh+ top speed. He’s much more interested in bulk low-speed wheelie power. This 60-tooth pizza tray gives the F4i an obscene amount of front wheel lift, but it’s still remarkably rideable even if it howls a bit on the freeway. The speedo will now be way out, but that’s okay because it’s sitting in the corner on a pot plant and probably won’t go back on. A big sprocket like this one, by the way, won’t help you learn to wheelie if you’re still too scared to hoist a minger on a stock bike - but once you’ve got some skills it’ll help you slow your wheelies down. Walking pace is the aim for serious stunters.

1:45pm: Twin rear grabbers

 

One of the first things most people notice when looking over a stuntbike is the two levers on the left bar - one’s the clutch, the other’s a secondary rear brake. FUF’s resident clown Jia explains: “the back brake’s all you’ve got to stop yourself flipping arse over tit in a wheelie - but we spend a lot of time standing on the seat, feet over the handlebars, that sort of thing. You might bring the bike up on the clutch, but after that you’re riding the rear brake, either with your right foot or your left hand.” Nam’s decided on a twin-caliper bracket from HoHey Designs, with an extra rear caliper from the wreckers and a long braided steel line up to the left handlebar. Again, it’s pretty much a bolt-on.

2:15pm: Stubby cooler?

 

Nam spends half an hour pulling the gorgeous Micron pipe apart and cutting both the inner and outer tubing down to about half size, welding the inner back together and picking the best of the insulating fibreglass to pack it out with. For the most part, it’s just because he likes the look of a stubby exhaust - but there’s the added benefit that once the outer is all scratched up (then rotated and scratched up again) he’s still got another good section of outer tube to replace it with for shows where the bike needs to look tip-top.

2:45pm: The noble Twelve-Bar 

Motorcycles are designed primarily to be ridden horizontally. Taking them to vertical (or 12 o’clock, hence the name) tends to smash and scrape expensive ducktails and legally compliant tail-lights, which is why most stunters weld extended metal plates onto the subframe to protect them. With the right geometry, a bike can be “parked” vertically on its twelve-bar, which is bound to help save space in Nam’s garage. He welds it up from scrap plate steel, and sticks on a bit of titanium so he can spark it up for the laydeez.

3:45pm: Hammertime

 

Up until this point, all Nam’s bike mods have been reversible, which makes this step somewhat of a point of no return. Highchairs, spreaders and several other tricks start with the lads sitting up high on their tanks and pulling wheelies, and when you’re near vertical with your legs over the handlebars, you want something to hold your butt in place. Nam takes a hammer and mallet and methodically dents the top of the tank into a half-scoop big enough for his skinny arse. If the poor abused Honda’s doting previous owner could see this, she’d cry.

4:15pm: A face only a father could love

 

With that, there’s little to do but fit a front end that’s got enough lights and indicators to get this puppy street-legal. The F4i won’t run without its tilt sensor, so that’s quickly bypassed with a bit of wire and some lecky tape, and a streetfighter headlight mask with some dinky front indicators is fitted, hiding a tangle of wires. It’s ugly as hell, but frankly that’s the way I like my motorcycles. The tail-lights and ducktail slip back on in minutes, then it’s tools away and there’s only one thing left to do…

5:00pm: Test Ride

 

Nothing to see here, officer! 

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