Brad Monk is a racer. Sure, he has a day job, but come Sunday, he’s a racer—and this is his race bike.
If you’re wondering if the combo is effective, it most certainly is. In Canada’s vintage road racing Heavyweight class, Brad took home the overall title this year. And the Yamando’s had success Stateside too.
The builder—or should we say engineering genius—of this mad machine is retired racer Toivo Madrus. Tovio co-owns the bike with Brad, and has been fine tuning and rebuilding this beast for literally years.
“The Yamando MK V wasn’t born overnight,” says Brad. “It’s actually the culmination of four previous versions, each one improving on engine angle and position, and engine performance that started at around 65HP, to what is now over 80HP.”
Yamaha and Norton seem an unlikely pairing (we’re more used to seeing vintage Triumphs offer up their engines), but Brad explains the thinking: “For anyone who’s ever ridden an XS, they can tell you about the extraordinary vibration this motor throws at you.”
“The solid mounted XS race engines create a vibration so extreme, they actually make the bike a challenge to handle, and in the end will rob you of speed through cornering and straight acceleration. And all the while, you’re losing feeling in your hands going down the track.”
“This problem only gets worse when the XS engines are modified to create more horsepower which of course equals more vibrations. So much so, it’s very common for XS engines to literally shake the bike apart, even through your lock wire and gallons of Loctite.”
Norton’s Commando frame was praised in its day for its light weight and excellent handling. But it’s also known for its isolastic engine mounting system—which uses rubber mounts to effectively ‘float’ the motor inside the chassis, without bolting it directly to the frame.
It’s just the thing to rein in the unruly XS power plant. “Even the exhaust mounts allow the hand made exhaust to slide forward and backward as the revs go up and down,” explains Brad.
Getting the Yamaha engine to fit was quite a task though. It’s wider than the Norton mill, so it had to be relocated up and to the right, with a new rear mounting subframe, and modded front mounts that still make use of the isolastic system.
“Needless to say, the challenge of getting the engine to sit in the frame exactly right was important,” says Brad, “otherwise the Norton frame would crack with the aggressive nature of the XS engine. It took Toivo many years to find the sweet spot for the two things to get along.” Moving the engine forward helped sharpen up the handling too.
The chassis was revised further with a chromoly swing arm from CMR in Belleville, Ontario. Toivo installed a set of 38mm Yamaha FZR600 forks with emulators up front, and a pair of Works Performance shocks out back.
The fuel tank is a hand-made aluminum number from CMR, and the tail is a hand-made fiber glass item, based on an original Herb Becker mold. Toivo also added Vortex clip-ons, a Scitsu racing tachometer and custom-made rear sets.
There’s a dual disc brake setup on the front wheel, and a CanAm drum brake on the rear. The detail goes deep; a custom oil cooler, hand-made cables and one-off sprockets are just the tip of the iceberg.
Oh, and it’s not a ‘650’ any more—Toivo installed a 750cc kit from Mike’s XS a few years ago. In the last twelve months, he’s fettled it further with stainless steel valves, an upgraded cam, a Kibblewhite spring kit, and 38mm Mikuni carbs.
Nothing’s been left alone. The crank, ignition and billet clutch basket are all new, and the primary gear ratios have been revised too. Porting was handled by Tim Speigleburg.
“Toivo did ninety percent of the work in house, about 250 hours,” says Brad. “Not counting about 150 hours for each for the four earlier Yamandos that lead to this MK V.”
“Toivo always says, ‘If it was easy…everybody would do it!’”
We’re impressed. Who’d have thought that the spirit of the original Tritons would live on in the 21st century, and in such an unusual way?
Photos by Andrew Wilcox.