The Middle Child: A 429cc two-stroke street & circuit weapon…
In 1983, Yamaha unleashed the RZ350, the ultimate evolution of the two-stroke RD series powered by a liquid-cooled 347cc parallel twin featuring the Yamaha Power Valve System (YPVS). Also known as the RD350LC or RD350 YPVS, this two-stroke street demon weighed just 371 pounds with the tank half-full and offered 52 horsepower at 8750 rpm — good for a quarter-mile time of 13.2 seconds at 99 mph. But the RZ was about more than the numbers:
“The RZ350 is the most modern and last legal street-going two-stroke sold in the US. In the first full test, we said our July 1984 cover bike rated a ‘perfect 10’ on the fun scale.” —Cycle World
Enter our friend Andrew Graham of Virginia’s Trident Cycles, who’s been riding, building, and restoring bikes for nearly a decade, calling it an “obsession that’s rapidly spiraled out of control” — our kind of guy! Back in 2018, we featured his SR250 scrambler. Now he’s back with a building we’ve been following for quite some time, an ’88 RZ350 that he built just for himself:
“I have always been a fan of two strokes and 80s sport bikes, especially ones with ¾ fairings. The plan is to get some good track time with the bike. It isn’t the most street-friendly and the motor is much better suited for the race track.”
As some of you probably know, a non-YPVS version of the RZ350 engine was used in the Yamaha Banshee ATV, and Wicked Motorsports of Garden Grove, California, is legendary for tuning these engines. The motor was bored and stroked to 429cc, featuring Wicked Motorsports chambers, cylinder head, and porting. Says Andrew of the riding experience:
“In one word, terrifying. The power band is narrower than a gnat’s behind and when it hits…it hits.”
The RZ is also running GSX-R1000 forks, upgraded brakes, a custom Nitron rear shock, and an RGV250 VJ23 swingarm — one of the most challenging aspects of the build:
“It really stretched my fabrication and engineering skills…. Getting this all sorted was by far the most fun, though.”
The Miami Vice paint scheme, laid down by Krazy Sprayz of Richmond, is a perfect match for this wild 80s hot rod and its outrageous engine, and our friend Sean Skinner of MotoRelic fabricated the stays for the Fiberman endurance fairing — matched to an RD350 YPVS F2 tail section. All in all, this is one of the evilest RZ’s we’ve seen, a water-cooled two-stroke rocket that’s sure to turn heads on the street and track.
Below, we get the full details on the build from Andrew himself and more photos from photographer Willie Graham (@williegraham1000).
Yamaha RZ350 “Middle Child”: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
This is my third full custom motorcycle build, second one to be featured on BikeBound, and by far the most extreme out of any of my motorcycles. I have been riding, building, restoring, and working on bikes for about nine years now. Motorcycles get to be my creative outlet.
• What’s the make, model, and year of the bike?
The base of the bike is a 1988 Yamaha RZ350. (Frame and bottom end of motor only.)
• Why was this bike built?
The bike was built for me. I have always been a fan of two strokes and 80s sport bikes, especially ones with ¾ fairings. The plan is to get some good track time with the bike. It isn’t the most street-friendly and the motor is much better suited for the race track.
• What was the design concept and what influenced the build?
I think it’s pretty obvious, but I had to go with the “Miami Vice” color scheme. I sketched up a paint scheme and Michael McCauley of Krazy Sprayz in Richmond, VA really nailed my vision for the paint.
• What custom work was done to the bike?
• Bored and stroked to 429cc
• Barrels ported and cases matched by Wicked Motorsports (IG @wicked_motorsports_atv)
• Wicked Motorsports Cylinder Head
• Wicked Motorsports Chambers
• Hinson Billet Clutch
• Suzuki GSXR1000 Front Forks and Wheels
• Wave Rotors
• Brembo GP4RS Calipers and RCS19 Master Cylinder
• Custom Nitron Rear Shock
• Suzuki RGV250 VJ23 Swingarm
• Suzuki SV650 rear wheel machined to fit the swingarm and frame.
• Ducati 999 rear caliper and master cylinder
• Koso Gauge – Tachometer with shift light and coolant temp
• Motogadget m-unit for the brains of the wiring harness
• Apex Racing Development Switches (IG @apexracingdevelopment)– Kill Switch, Power Switch, Radiator Fan, “Racing Mode” Switch (power to all the lights are killed)
• Front Fairing is an endurance fairing from Fiberman
• Front Fairing Stay fabricated by Sean Skinner of MotoRelic (IG @motorelic)
• Tail section is an RD350 YPVS F2 race piece
• Seat was done in my shop, one of the more difficult pieces that I undertook
• Does the bike have a nickname?
“The Middle Child” – It’s a bit loud and obnoxious.
• Can you tell us what it’s like to ride this bike?
In one word, terrifying. The power band is narrower than a gnat’s behind and when it hits…it hits.
• Was there anything done during this build that you are particularly proud of?
Getting the rear swingarm and wheel fitted to the frame was by far the most challenging part. It really stretched my fabrication and engineering skills. All of the machining to get this done was done in my shop with my tools. The toughest part was getting the wheel centered on the frame and getting the sprockets lined up. I’m running an offset front sprocket, but I still had to machine the cush drive down to get the chain to be aligned and the wheel centered. The wheel spacers are all custom; swingarm pivot sleeve has been machined to fit the swingarm bearings; rear shock linkage was designed in house; brake caliper bracket modified to clear the rotor bolts.
Getting this all sorted was by far the most fun, though.