Source: BikeEXIF –
Purpose Built Moto is no one-trick pony. The Australian workshop is up for anything, with a portfolio that boasts a wide variety of brands and custom build styles. Even so, they raised a doubtful eyebrow when the brief for this custom Yamaha Virago landed in their inbox.
“I wasn’t sure if we would take on this build,” says the workshop’s founder, Tom Gilroy. “The XV750 isn’t one of my favorite bikes to work on, that’s no secret. I find them over-saturated in the custom world, and often undercooked.”
In the end, the enthusiasm of his client won Tom over. Hands were shaken, and the bike was delivered to Purpose Built Moto’s Gold Coast shop with a box of extra parts.
“He was passionate and super keen to have a purpose-built machine, and had his heart set on his 1981 Yamaha XV750 Virago Midnight Special,” Tom adds. “He’d already started sourcing parts and doing a few modifications. From this, I could tell he wanted the job done properly.”
The bike came to PBM with a Yamaha R1 front end, Cognito Moto yokes, and the rear wheel from a different model Yamaha XV. The project’s goals quickly became clear; better performance and handling, and a sharp and modern disposition. An aggressive under-tail exhaust was also on the wishlist.
Tom’s notes also included one very specific job; “fix that ugly swingarm.” So the PBM team ditched the square-tubed OEM swingarm and welded up a fetching trellised chromoly unit instead. A custom rear shock from Ride Dynamics props up the rear end.
Extra care was taken to tweak the bike’s ride height, including some deft engineering to lengthen the front forks. “Straight-swapping the XV750’s forks for the R1’s makes it far too low,” explains Tom. “It looks great, but one speed bump a little too quick and you’re left with a total loss oil system—no bueno.”
Next, PBM tackled the subframe and wild exhaust system all in one go, cycling between various areas of the bike to make sure everything fit together perfectly. It soon became apparent that the rear engine mount was going to be in the way of the rear cylinder’s exhaust header, so Tom and his team hollowed out and re-braced that section of the frame.
The stainless steel headers now snake their way around the engine and up through the tubular subframe, exiting in a pair of burly box mufflers. An abbreviated saddle is perched on top, with the license plate and taillights now hosted lower down, on a custom-made bracket. Looking at how well each part complements the next, all that effort was worth it.
Next, PBM turned their attention to the XV750’s engine. Or rather, their relatively new engine-building division, Purpose Built Performance, did.
In went new high-compression pistons, upgraded conrods, and bigger valves. The crew also rerouted the intake from the stock in-frame airbox to a single DNA filter, and then trimmed off the original airbox breathers and filled in the gaps. After some judicious porting, machining, and fettling, the now 1,050 cc V-twin was ready to start blowing through clutches… which is exactly what it did.
“On the dyno with my mate Jamie at Dynomite Moto, the bike would reach 45 to 50 horsepower at the rear wheel and start to spin the clutch,” Tom tells us. “We’d already upgraded to a new set of plates and performance springs but evidently that wasn’t enough. The solution was to use some Barnett plates and springs, suited for a stage two Harley Sportster, that allowed the XV to put its power down to the road.”
“The power upgrade is reflected in the sound of the engine too. While most XVs sound poppy and hollow, this bike has a nasty bark closer to a cammed Sportster than anything else. One change I would make would be the removal of the single carb manifold—this was a supplied part that isn’t a great fit or design.”
“The XV750 isn’t designed to run a single carb, so I’d bet with a twin Mikuni setup we could safely milk even more power out of the upgraded engine.”
With the original Yamaha fuel tank repositioned up top, and a handmade fender out front, all PBM needed now was a suitable color scheme. The wheels were already powder-coated in bronze, so initial discussions of black or red eventually turned to something that would pop against the wheels. PBM’s go-to paint guy—Justin at PopBang Classics—came to the rescue with a stunning metallic olive green livery.
PBM dipped into their parts catalog to get the build over the finish line. A 7” LED headlight sits up front, followed by an aftermarket dash, and clip-ons fitted with PBM switches and mirrors. The three-in-one taillights are a new PBM product, specifically designed to be visible from all angles.
PBM’s take on the venerable Yamaha Virago looks wild and uncompromising, with enough of a growl to aggravate the neighbors. But does it have the bite to match its bark? Tom says yes.
“Once it was run in, it was time to stretch its legs on the test ride. It did not disappoint; power wherever you need it in the rev range, just rip the throttle and go.”
“I was having a blast on some back roads, and when I went to take off with a bit of gusto on the throttle, that front wheel lifted right up and held up until I changed into second.”
“One of the only Virago front wheels to ever leave the road, I thought.”
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