Source: Bike Bound
[[{“value”:”Photo: Revival Cycles / Handbuilt Show
Rocket Science: CB750F Cafe Racer from a SpaceX Propulsion Engineer…
In 1975, Honda unveiled the CB750F Super Sport, a significant redesign of the original CB750K that included both styling and performance enhancements. The engine boasted 10% more horsepower thanks to a freer-flowing 4-into-1 exhaust and slightly higher compression ratio. Meanwhile the front end got an inch more rake and 3/4″ more trail, and the swingarm was extended 3/5″ — geometry tweaks for better stability at the higher speeds that Super Sport riders might ride.
In the looks department, the upgrades were subtle but impactful, intended to give the CB750F the sportier appearance upgraded “Original Superbike” deserved.
“Have the sheet-metal guys stretch that gas tank out a little, not much, just a smidge to give it a slightly elongated, racy appearance; and hide the gas cap. Then tell the seat people to make a little fiberglass extension to fit the back of the saddle, sort of a faux bum-stop that some single-seaters had. The fast look was born.” –Rider
Enter our new friend Joe Shifrin, a native New Englander who grew up racing motocross with his family:
“Every weekend was a family event for us. My brother, dad, and I all raced and my mom was our diehard cheerleader and pit crew.”
Today Joe lives in Texas and works as a Principal Propulsion Engineer — aka rocket scientist — for SpaceX. He’s been slowly converting his garage into a workshop, and this build is the first to roll out of the space.
The CB750 is a highly popular donor these days, but Joe has different reasons than most to choose the CB750F Super Sport: his dad owned one, bought new from the showroom floor in 1970.
“He loved that bike, but two years later he sold it to purchase an engagement ring for my mom. It was the last road bike he had and if it came up in conversation, he was always quick to joke that my mom wears it on her finger now.”
So Joe picked up a ’77 CB750F and set out to make it his own, preserving the charm of the original Super Sport while modifying it according to his own vision.
“77 Redux is a retrospective redesign of the 1977 Honda CB750F Super Sport. A design of this pivotal vintage with the perspective of the Sport and Super Sport bikes that followed it.”
Joe gives us the full details on the modifications below. The original frame, engine, brakes, and wheels were refinished, mainly in factory colors (including the black engine), while the original tank was restored and painted Porsche Carbon Gray with metallic bronze pin-striping courtesy of Moto Jay Refinishing.
The seat and tail were designed to follow the original lines with the addition of a body line that extends from the tank through the tail, and the custom taillights are inspired by the superbike lights of the 1980s. Both the TIG welding and leatherwork were new challenges for Joe. In order to eliminate the bulky oil bag for the dry-sump engine, he created an oil tank/cooler hidden inside the tail that doubles as a shortened rear fender — nice!
From a performance angle, the “77 Redux” is running CR29 Keihin carbs, a Delkevic 4-into-1 exhaust, Dynatek ignition, Ikon rear suspension, progressive fork springs, tapered roller steering bearings, and one very trick item to keep tabs on everything: a custom data acquisition system that’s packaged with the battery under the seat!
“This system monitors engine performance along with other metrics and communicates wirelessly with the tachometer display. The tachometer is a digital display embedded in a new case that I’ve re-encased the original speedometer in. So it’s an all-in-one digital/analog gauge with the original face.”
We told you he was a rocket scientist! The 77 Redux looked amazing at the 2024 Handbuilt Show, and we can’t wait to see what rolls out of Joe’s garage next. Below we talk to the man himself for the details and backstory on the build.
Honda CB750 Super Sport Cafe Racer: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your workshop.
I grew up in New England, racing motocross from the time I was on a KTM 65 until I was a teenager and have always had a love for motorcycles. We raced in the New England Motocross Associate from April to October and every weekend was a family event for us. My brother, dad, and I all raced and my mom was our diehard cheerleader and pit crew. After many years and many injuries, we kind of grew out of it. After that, I kept an interest in motorcycles, particularly Cafe Racers, but I went off to engineering school, then moved to Los Angeles for graduate school and was never in a position to actually set up a shop.
Finally, 2022 was the right time to start my first build and start to pursue a passion that I’ve dreamed about for most of my life. Of course, for my first build, I was partial to the CB750; not because it’s a classic donor bike for a Cafe Racer, but because it’s always been a special to me because of the stories I grew up hearing about my dad’s CB750. In 1980, he bought a brand new Honda CB750F Super Sport. He loved that bike, but two years later he sold it to purchase an engagement ring for my mom. It was the last road bike he had and if it came up in conversation, he was always quick to joke that my mom wears it on her finger now. So that’s how I ended up going with the 1977 CB750F, which I ultimately built into 77 Redux.
I now live in Texas and work as a Principal Propulsion Engineer for SpaceX. As a propulsion engineer for over a decade there I’ve worked on a wide range of projects and have been a part of the design and development of almost every rocket engine SpaceX produces. On my nights and weekends I’ve slowly converted my garage into my motorcycle shop — replete with welding and forming tools, bench top machine tools, 3D printer, bike lift, etc. Longer term, I hope to move into a larger space and take on a wider range of motorcycle projects.
• What was the inspiration and design concept for the build?
When Honda introduced the CB750F in the mid 1970’s, they made some of the most significant changes to the iconic CB750 to date; all geared toward a sportier ride and overall design. In 1977 the Super Sport took its final form as the CB750F2, this was the last redesign before the introduction of the DOHC CB750 in 1979.
77 Redux is a retrospective redesign of the 1977 Honda CB750F Super Sport. A design of this pivotal vintage with the perspective of the Sport and Super Sport bikes that followed it.
• What custom work was done to the bike?
The build incorporates fully restored finishes on the original engine, frame, brake, and wheel components. Factory color and finish was used on the majority of components (many people question the black motor — it was black on the 1977/1978 Super Sport).
The original fuel tank was restored and painted in Porsche spec Carbon Gray with metallic bronze pin-striping by Moto Jay Refinishing.
The 77 logo on the tail and featured in the custom parts throughout, takes inspiration from the original “750Four” Logo on the side of the air box cover. The font used was unique with the double stripe for the CB750F2 (1977/1978).
The custom Napa leather seat and tail are designed to follow the lines of the original seat and tail (except the tail lights), with the addition of the body line that follows from the tank to the tail.
The custom tail lights are intended to evoke the superbike tail lights of the early 80’s while retaining the directional focus of the rest of the design toward a focal point behind the tail.
Custom low profile oil tank/cooler that forms the rear fender and license plate holder. This visually eliminates the tank typically seen under the seat on SOHC CB750’s.
Performance modifications: Delkevic 4-into-1 exhaust, CR29 Keihin carbs, K&N filters, Dynatek Dyna-2000 configurable electronic ignition system, Ikon rear suspension, progressive front fork springs, tapered roller steering bearings.
• Can you tell us what it’s like to ride the finished bike?
Riding the bike for the first time was a thrill. Not only was it something I had dreamed about building for years, but it felt great to be back on a bike again. It was cool to get to know the nuances of my own creation.
• Was there anything done during this build that you are particularly proud of?
There are a few things I’m proud of, I’ll list them out below.
1. The fabrication work of the tail and seat — all TIG-welded aluminum as well as the leather work on the seat were all new processes for me. So this is more of a personal accomplishment, but I’m proud of those parts because I feel I was able to achieve my design goals.
2. One of the biggest challenges was to visually open up the triangle in the frame under the seat to get the classic, lean cafe racer look. For a SOHC CB750, that’s particularly difficult because of the remote oil tank required for the sumpless engine. To solve this problem I built a custom oil tank that is hidden in the tail and forms a shortened rear fender. While I was at it, I added internal and external cooling fins as well as a cross-flow return path for the oil return line to improves oil cooling. It also has an embedded light where the license plate goes, lighting under the fender and rear tire.
3. This last one is still in progress, but I’m proud of the work I’ve done on it and I think it’s going to be really cool. Under the seat I’ve built a full data acquisition system that will actively monitor and record engine sensor data (temperatures, pressures, rpm), compute ride metrics, and many other things. That system works wirelessly to transmit all of this data to a digital display that I’ve embedded in a case for the speedometer. The speedometer itself is the original unit from the bike, with a replica of the original face and the new aforementioned case.
• Is there anyone you’d like to thank?
I’d like to thank my wife for supporting me in taking on this project, despite our super busy schedules and the birth of our first child throughout the process, she’s been super supportive of my passion.
Follow the Builder: @joeshifrin
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