Vic Shield’s RZ421-Powered MZ Skorpion!
In 1994, former East German motorcycle maker MuZ — aka MZ — introduced the Skorpion, a single-cylinder sport bike with a race-style chassis and 660cc Yamaha engine. This crossbred machine soon earned itself a cult following, as riders realized what a lightweight, razor-sharp canyon-carving weapon they had on their hands.
“Cornering the Skorpion is so entertaining that your boot toes may very well wear thin. ” –Cycle World, 1995
The bike even sparked its own racing series in some countries, the Skorpion Cup, while other riders campaigned the bike in Supermono and singles classes.
Enter our new friend Vic Shield of the UK’s Vic’s Custom and Classic Autos, who’s been into motorcycles since he was 12 — back when he and his brother dug an unloved CB200 from the bottom of the garden, got it running, and took it out into the woods.
After working as a coachbuilder and panelbeater, Vic started his own auto restoration company — though his heart still rolls on two wheels:
“I still do some restoration work on cars, but it’s specials and custom motorbikes that I have started to do more of now. The trouble is when I build a special I can’t part with it…lol.”
This project started when he picked up an MuZ Skorpion whose 660cc Yamaha single was worn out…and someone told him he couldn’t fit a two-stroke parallel-twin from an ’86 Yamaha RD350YPVS (RZ350) into the Skorpion frame.
“The best bit of this build is the fact that I was told it couldn’t be done…and I did it to prove the skeptics and purists wrong.”
One of the UK’s foremost two-stroke tuners, John Floyd of Floydy Racing, worked his magic on the motor, which boasts a stroker crank, 421cc Athena big bore kit, billet cases, lock-up clutch, Vape ignition, and 36mm carbs. Vic says the motor now puts out 90-95 bhp, drinking premix at 15 mpg!
Vic puts his panel-beating skills to use with the bespoke aluminum bodywork — completely handmade — and the rest of the bike has been upgraded with Öhlins suspension, Brembo brakes, and custom-laced wheels.
Weighing just over 220 lbs with more than 90 horses of two-stroke fury on tap, “The Mutant” is a beast on the street:
“The bike rides so well, the original MZ Skorpion is used quite a bit in the singles racing class…and the suspension upgrade with Öhlins makes it handle like it’s on rails, plus being just over 100 kilos it’s VERY light.”
Below, we talk to Vic for the full story on this hybrid German-Japanese monster!
421cc Yamaha-MZ “Mutant”: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
I’ve been into bikes since I was 12. My dad had an old Honda CB200 that was sitting unloved at the bottom of the garden, so my younger brother Dan and myself decided to get it running and rode it up the woods, about a mile from our house…that was when our love of motorcycles started.
Over the years I’ve owned far too many bikes to remember — however, it’s the ones that I build or modify I enjoy riding most.
Back in the early 1990s I built one of the first LC hybrids, a Yamaha 250LC that I had destroyed the engine in…so I fitted it with a Stan Stevens race-tuned RD 375cc YPVS motor.
I did my apprenticeship with the National Bus Company as a coachbuilder, and this taught me fabrication, welding, painting and trimming…I taught myself mechanics and auto electrical work over the years that followed.
After being made redundant from a large commercial bodyshop when the credit crunch hit in the early 2000s, I went to work in Norway as a panelbeater.
My wife and myself were there four years and I missed everything that England has to offer…good grub and beer, bike shows and motorsport, plus at the time riding my old Triumph 1200 street fighter.
That was over 10 years ago. We came back and I set up a vehicle restoration company…I love classic motors but my heart has always been into motorcycling…that’s my dad’s fault, I was brought up with them from a very young age.
I still do some restoration work on cars, but it’s specials and custom motorbikes that I have started to do more of now. The trouble is when I build a special I can’t part with it…lol.
That’s a brief bit about me.
Tell us about your bike…
This project started with an old ex track bike RD350YPVS and a MuZ Skorpion. I loved the lightweight frame and minimalist appearance of the MuZ; however, the old 660 lump was tired and heavy.
I took the engine to John Floyd (Floydy Racing) to work his magic and tuned it as much as possible with a stroker crank and 421cc Athena kit. Billet cases, lock up clutch, racing ignition, and 36mm carbs.
The exhausts are modified TZ race pipes, and to keep it cool, a GSX-R radiator with go-kart thermostat.
It has Vape Racing ignition and EGT engine gas temperature sensors welded into the headers and this gives an accurate reading of what is happening inside the bores…these start to flash red at 610 degrees, so it gives you the chance to back off on the quick action throttle before the engine goes into meltdown.
The bodywork is all handmade from aluminium and the wheels are Talon hubs strung to lightweight racing alloy rims. Brembo brakes stop the bike and Öhlins keep it on the road.
The bike has a daylight MOT and drinks pre-mix at 15mpg. Environmentalists will love this.
• Can you tell us what it’s like to ride the Mutant?
The bike rides so well, the original MuZ Skorpion is used quite a bit in the singles racing class; the frame, I was told, is built by Tigcraft and the suspension upgrade with Öhlins makes it handle like it’s on rails, plus being just over 100 kilos it’s VERY light.
• Any idea of power output?
Depending on fuel and weather conditions, between 90 and 95 bhp.
• Is there anybody you’d like to thank?
I would like to thank my mate Nicholas Kelly for the aluminium welding and another John Floyd for his top quality engine tuning.
• Was there anything done during this build that you are particularly proud of?
The best bit of this build is the fact that I was told it couldn’t be done…and I did it to prove the skeptics and purists wrong.