A 70s Café Smoker from the Netherlands…
For many of us, at some point in our lives, motorcycles have been more than just a hobby, adventure, or even a profession — they’ve been a lifeline. The wind and throttle seem to have their own healing powers, while tackling a full-on build can be immensely grounding, giving us purpose and direction during hard times.
So it was for our new friend Marthijn Kip of the Netherlands, a mechanical engineer who pulled off his first project at the age of just 14: a moped-engined pocket bike with 4.5″ wheels!
“The frame and seat-tank combo we (Dad and myself) built from scratch. I have built several bikes since then, varying from race-ready MX50 (moped cross) bikes to a supermoto.”
Marthijn comes from robust motorcycle stock. His father is a 50cc grand prix racer who builds his bikes from scratch during the harsh Dutch winters, then races in the summer. So when a family tragedy made it hard to remain positive, Marthijn found his way back to motorcycles, giving himself a project to occupy his mind:
“I wanted to build at ‘true’ 1970’s café racer. Built with ample budget and means. As if I got it from my dad and kept it those 50-odd years.”
For the donor, he chose one of our favorite two-stroke street bikes, a Yamaha RD350 — specifically, a 1975 Yamaha RD350B:
“I fell in love with the RD and I just wanted to sharpen the lines already there. Almost all the parts used in the build came from either swap meets or the breakers yard. And are pre-1985.”
We love that Marthijn kept the modifications as period-correct as possible, and then there’s his wealth of fabrication work — fuel filler cap, gauge cluster, rear sets, mufflers, side panels, and more — all done with the most basic shop tools:
“I’m really proud of the parts I made from scratch. I have a workshop with limited tools, so most is done by drill press, hacksaw, and perseverance — this is almost meditation, and builds karakter.”
The result is a leaner, sharper, more powerful RD capable of surprising some of the modern machinery on the Dutch roads:
“It’s a blast to ride, it’s nice and flick-able in the corners. It brakes on a dime to a full stop. With the mild tuning already done it can keep up with most bikes — it’s fun to tease the newer class 600s with.”
Below, we talk to Marthijn for the full story on this gorgeous green RD350 café racer.
Yamaha RD350B Café Racer: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
I’m Marthijn, 41 years of age, married. I live in the Netherlands. I started riding motorcycles at age 8 on a Honda XR75. At the age of 14, I built my first (project) bike, a pocket-bike on 4.5” wheels with a moped engine. The frame and seat-tank combo we (Dad and myself) built from scratch. I have built several bikes since then, varying from race-ready MX50 (moped cross) bikes to a supermoto.
Currently I work as an mechanical engineer in the field of mechatronics, and I solely build bikes as a hobby in my spare time.
• What’s the make, model, and year of the donor bike?
This build is based on a Yamaha RD350B from 1975.
• Why was this bike built?
I build this bike to occupy my mind during a time when I struggled to keep positive thoughts. It’s my personal bike. And I wanted to keep my “heritage” going, as I learned a lot from my dad growing up with bikes — I tried to show my skills.
• What was the design concept and what influenced the build?
I wanted to build at “true” 1970’s café racer. Built with ample budget and means. As if I got it from my dad and kept it those 50-odd years. Dad is still with us, and is a self-made 50cc grand prix racer who practically builds his bikes completely from scratch during the winter, to compete in the summer.
I also fell in love with the RD and I just wanted to sharpen the lines already there. Almost all the parts used in the build came from either swap meets or the breakers yard. And are pre-1985.
• What custom work was done to the bike?
– Repainted metallic green
– Re-upholstered Giuliari seat
– Swapped rear suspension for fully adjustable Koni’s (proud to be Dutch)
– Fitted a custom ECU-controlled ignition
– Fitted clip-ons
– Fitted lamp brackets to lower the original headlight
– Made my own gauge cluster
– Made glassfiber side panels with air scoop
– Fitted expansion cambers
– Made folding rearsets with a TZ-style cable operated rear brake
– Fitted a Kreidler moped rear light converted to LED
– Fitted a Rickman-style front fender with an oversized mounting bracket to look like a stiffener
– Fitted a 320mm front brake disc with a Brembo P8 caliper and a 11mm Brembo master cylinder.
– Fitted a large K&N cone air filter (from a Rover V8) to the Y-boot
– Fitted a YZ250 fuel tap to keep the fuel guzzling
– Fitted Domino grips with a ridge on the throttle
– Polished all aluminium parts
– Fitted oval blinkers
• Does the bike have a nickname?
This bike remains un-named. I know its intention, which doesn’t need to be named. The bike and build process did their job and provided a (healthy) distraction.
• Can you tell us what it’s like to ride this bike?
It’s a blast to ride, it’s nice and flick-able in the corners. It brakes on a dime to a full stop. With the mild tuning already done it can keep up with most bikes — it’s fun to tease the newer class 600s with.
At traffic lights or at any stop it’s a great conversation starter. The green makes it standout; the exhaust and intake make its presence heard; it’s hard to miss but still it appeals to most people. I guess the blue license plate helps (which indicates that it’s older than 50 years).
• Was there anything done during this build that you are particularly proud of?
I’m really proud of the parts I made from scratch. I have a workshop with limited tools, so most is done by drill press, hacksaw, and perseverance — this is almost meditation, and builds karakter.
• Fuel filler cap, made from billet to look TZ-like, without the use of an MILL!
• Gauge casings and cluster. I pressed the gauge casings from aluminum plate and pipe, which was my first time forcing metal in to a shape with a hydraulic press.
• The aluminium mufflers with end caps.
• Rear sets and cable operated rear brake.
• Glasfiber side panels with functional “ram-air” scoop for the air filter.
• Making the pickup for the electronic ignition.
• Shortening the shock absorbers.
• Used beer-bottle caps to plug the holes in the top yoke.
