FEATURE - 1985 Honda CBX 250 custom
Words Mike Ryan
Photos: Mike Ryan and Darren Robinson
There are all sorts of motivations behind building custom bikes. It may be about testing skills, the challenge of making new out of old, reviving childhood memories or simply spending time with mates on the spanners. Often, though, it’s just for fun.
Darren Robinson certainly fits into the latter category, and even though he builds bikes to customer order through his ‘DR Customs’ business, the bikes he’s built for himself over the years have been enjoyed on roads, race circuits, in the dirt and even on the salt.
The build shown here is another that was created for fun – specifically fun on the track at the Broadford Bike Bonanza.
A Bike for Broadford
After he’d scored a second place trophy at the 2016 Deus Bike Build Off with a Yamaha TT/XT hybrid café racer and taken his 1980 Yamaha salt flat racer to Lake Gairdner in 2017, Darren set his sights on the 2018 Broadford Bike Bonanza. Specifically, Darren wanted to ride Broadford’s road race track.
As good as his previous builds were, none were really suitable for circuit work, so the search for a ‘Bike for Broadford’ began.
“I was after a lightweight bike – something with potential for the track, as well as something different,” Darren explained.
As most of you already know, the Broadford Bike Bonanza is a non-competitive event for classic bikes only. For the 2018 Bonanza, the cut-off was pre-1990, so Darren’s future track bike had to be a 1989 model or older.
“The challenge was to convert an unassuming road bike to a great handling, quick, custom historic track bike that would be easy to maintain and fun to ride.”
In November of 2017, the right bike from the right era – and at the right price – was found in the form of a 1985 Honda CBX 250. Darren jokingly called his find a ‘$350 eBay special’.
As you can probably imagine, there was a reason why the bike was so cheap…
Rough Start
This writer can remember a time when bikes like the Honda CBX 250 and Spada 250, Suzuki GN 250, Yamaha’s Virago 250 and Kawasaki’s ZZR 250 and GPX 250 seemed to be everywhere.
Nowadays, most of these learner-spec classics from the ’80s and early ’90s are rarely spotted. And if they are, they’re at opposite ends of the condition spectrum – either completely restored or absolutely knackered. What Darren had purchased for his Broadford fun machine was definitely the latter!
“The bike was in a very poor state, almost non-functioning, lots of damage and not maintained. However, it was generally complete,” Darren recalled.
A rattle can paint job on the frame hid poor paint underneath, there were cracks and missing tabs on the plastics and the motor wasn’t running.
“Most people would part the bike out or scrap it. However, I could see its potential. I also love the challenge of bringing a bike back from the dead and use my customising skills to build something unique.”
Strip Down, Build Up
Work started by stripping the bike down to the chassis and disassembling the engine and gearbox for inspection.
Most of the frame would remain untouched for the rebuild, but after media blasting, Darren did shorten the tail by about 10cm; removing the pillion grab rails and cutting off the pillion footpegs, too. The latter change weakened the area around the rider footpegs, so Darren welded in bracing pieces aft of the pegs.
All unnecessary tabs were then cut off and the welds smoothed before the frame was repainted in a silver not all that dissimilar from the factory colour.
The engine was next and, after being cleaned and freed up, was bored out to 254cc, with a larger Wiseco piston fitted.
Pocket porting and port matching on the manifolds would increase power, aided by a larger Mikuni carb. Sourced from an older Yamaha to suit this project, the carby was re-jetted and matched to a ram tube air intake that Darren made himself.
For the exhaust, the factory 2-into-1 header configuration was retained, but new (and much shorter) pipes were fabricated and a stubby muffler fitted.
Against a factory CBX 250’s 31hp (23kW), Darren estimates the larger bore and other engine changes have increased power to 40hp (30kW) – and improvement of almost 30 per cent.
On the factory 6-speed gearbox, opening it up showed no major issues, so most of it was left untouched for the rebuild, but new EBC sprockets and a stronger chain were fitted.
An EBC front brake disc was also fitted, along with an EBC 2-piston caliper and braided lines. The factory master cylinders were rebuilt and the factory rear drum brake retained.
Darren could have gone bigger and bolder with things like the braking or a custom swingarm, but updating too much would blow out the cost of the build and defeat its purpose. The mantra of the Bonanza is ‘no racing, just riding’. Yes, riders do cut some fast laps, but with no timing, there’s no point trying to be Marc Marquez!
Makin’ it Racy
With this bike’s track focus in mind, Darren next fitted a pair of aftermarket clip-on handlebars, topped with Posh grips. The factory levers were retained, but the mirrors were deleted and the factory instrumentation removed, too, replaced with a compact aftermarket speedo.
As this was to be a track-only machine, the headlight was made non-functional, the tail light deleted and the indicators removed, which meant the left-hand switchgear could be removed, too.
After deleting the indicators on the factory headlight fairing, Darren cleverly laid fibreglass over their position, so the shape remains and doesn’t look out of place on the finished bike.
Similarly, the factory Honda bellypan was retained and only mildly altered to suit the custom exhaust.
Darren next deleted the CBX’s factory sidecovers and tail unit entirely, replacing the former with custom-cut sheet aluminium and the latter with a stubby seat hump that he made from scratch out of fibreglass. As well as looking the part, this seat hump also houses a lightweight lithium battery.
The seat hump also dictated a new shape for the saddle, which Darren customised from the factory seat before having it retrimmed in marine-grade vinyl.
It’s worth noting at this point that the seat upholstery was the only item on this build that was outsourced: “I did all the design, fabrication, modification, paint, body mods, electrics, motor and assembly myself,” Darren explained.
With track performance in mind, Darren upgraded the factory forks with new spacers and heavier fluid, while a set of stiffer remote-reservoir shocks with preload adjustment were added at the rear.
To keep costs under control, things like the factory fuel tank, hubs and alloy wheels (16-inch front, 18-inch rear) were retained, but Darren did add track-rated Dunlop tyres.
Stripping the pillion seat and the rear plastics, as well as things like the lights and associated wiring, exhaust system and even the centre and side stands has obviously shed weight, but how much? All up, Darren says the finished bike weighs around 110kg – close to 20kg lighter than the factory weight of a CBX 250 – just what you want for increased agility on the track!
The Right Ratio
By early 2018, the mechanicals, frame, brakes and suspension had been sorted, which meant Darren could now focus on his favourite part of the build – painting and detailing.
“Deciding the final colour scheme with vinyl graphics and getting the balance right is always a challenge,” Darren said.
“I work on a three colour ‘60/30/10’ ratio. In this case, the primary colour is red, with silver the secondary colour.”
Rather than content himself with painting the tank, wheels and plastics, Darren extended that colour ratio theory to the engine, adding heatproof paint in red to the crankcases and head, with silver on the barrel.
Little details, like red for the wiring, air filter and even the valve caps keeps the theme going, while the cut-down smoked windscreen joins the tyres to serve as the ‘10’ in the 60/30/10 ratio.
The stars? Yeah, they’re a whimsical touch, but this bike was always about having fun and Darren has shown in his past builds that he isn’t afraid to push the envelope when it comes to paint and graphics. Those stars are also die-cut vinyl, so should the mood strike him, Darren can remove them.
The other thing you may notice is the ‘Ya Ha Racing’ script on the tank. This is a personal touch of Darren’s, applied to his salt flat racer and reflecting the fact that, even though this build was a Honda, most of Darren’s past projects have been Yamahas.
On Track and On Show
From start to finish, this build consumed five months of evening and weekend work, but crucially for Darren’s initial goal, it was ready – just! - for the NSW resident to bring it down to the 2018 Broadford Bike Bonanza.
When this writer encountered it at Broadford, it made an impression, hence its feature in these pages. Darren made sure he got plenty of track time on his creation and there’s no doubt this bike was a standout every time it was in action. Not bad when you consider everything from an Irving Vincent to big Japanese sportsbikes, classic Ducatis and even a hand-shift Indian was on the Broadford road race track that weekend.
OK, it may look good, but was all that work worth it and does the CBX perform? “Absolutely,” Darren enthused. “The bike is a dream to ride - light and responsive. It also corners great and sounds good. For a little bike, it has lots of go. And I get a big smile on my face undertaking and outbraking larger capacity and faster bikes!”
Following its Bonanza debut in 2018, Darren’s taken this bike to track days at other circuits, including Pheasant Wood at Marulan in NSW; a circuit that Darren says the CBX is particularly suited to, given its tight layout and high-camber corners.
When it’s not being enjoyed on the track, this custom CBX is being admired . . . inside.
“The bike is actually in my lounge room as a ‘mechanical work of art’ decoration when I am not riding it,” Darren laughed. “My salt racer is also in the house, in the hallway!”
As much as he likes looking at his bike, Darren also likes other people checking it out, hence his enthusiasm for taking it to events and track days. He says the responses he gets from people are great and motivate him for future projects.
As mentioned, Darren takes on commissions through DR Customs, so if you like what you see here and would like him to work some magic on a project for you, get in touch (Mob: 0498 662 282, email: [email protected]).
After its 2018 Broadford debut, Darren brought the CBX down again in 2019, but this year, he’ll be debuting a new creation at the Bonanza in the form of a 1980-model Honda CB 400 that he’s in the process of doing a full custom job on.
There were already plenty of reasons to get to Broadford for the Bonanza this Easter. Now there’s another one!
