1981 Yamaha XJ550 SECA

Original Article at
- Built in 2017

Automotive engineering is full of ideas that must have seemed great at the time but in the cold, hard light of day can tend to look a little less than inspired. Take Yamaha’s XV750 for instance. An unbreakable engine that not only goes and sounds great, but also serves as a stressed member that the rest of the bike is built on. True innovation, yes? Well hold your horses for a second, because there’s always the bike’s pneumatic suspension and that pesky starter motor to consider. Sure, they probably seemed like pretty good calls at the time, but bake them for 35 odd years and then try them on for size them and you’ll likely find something a little less than the next successful entry into the Motorcycle Engineering Hall of Fame. So you’ll understand the irony when I tell you that the very same engineers who designed that damned XV starter motor were also the ones who created this, the XJ550 SECA. Created for the original cafe racer set from the get-go, it’s turned into somewhat of an engineering classic over the years. And it’s number one fan? Here’s California’s Thirteen and Company to vie for the position.

 “When we first stumbled across the humble Yamaha XJ550 SECA, we didn’t think much of it,” says Thirteen’s Kyle Vara. He says his initial thought was to just get it running and maybe keep it as a great stock bike. “But once it was going, the bike was really impressive all-round. Then after a little research, we were not that surprised.” See, in 1981 Yamaha introduced their YICS induction control system, which called for an extra set of intake ports to be cast directly into the engine’s head. This allowed each cylinder to get two charges of air and fuel at the same time, making for much more efficient combustion. It also featured an all-new gearbox, completely surpassing that of its older brother the XJ650. “The XJ550 SECA is hands down one of the best 550s we have ever ridden straight out of the factory. So, understanding the potential of this little motor, we didn’t hesitate to rebuild it giving it the overall design we think it really deserves.”

Kyle an his team started by stripping the bike of all unnecessary parts, leaving nothing but a rolling chassis and gas tank. From there they were able to get a better understanding of the natural lines the stock set-up offers. “It was important for us to really emphasize the awesome design of the stock gas tank and we knew we had to make a seat that would compliment it. After a couple of renders on the computer, it was clear we had to go with a non-conventional cafe seat – and something created with modern Moto GP seats in mind.”

Once the seat was figured out, they moved into converting the front end. A beautiful, bright gold ZX10R front end from Kawasaki caught their eye and they knew that it would be a perfect fit for the build. With there being no off-the-shelf conversion kits for the bike, they had to make everything themselves. “We machined new head bearing races to fit the oversized stem. Then, utilizing the stock front wheel, custom wheel spacers were also machined to fit the bigger diameter axle the ZX takes. We also kept the stock ZX front break caliper.” The bigger dual piston calliper will stop on a dime, and then give you back 5 cents change.

“The seat was cut from genuine Italian leather and it sits on top 1 inch of quality foam. We used the stock headlight, but we decided to make our own bottom brackets to keep the upper fork area as clean as possible. We also installed an old rock guard headlight screen we had lying around.” The frame and wheels were then given a 3-stage gloss black paint job, and the wheels were then mounted with the inimitable Firestone Vintage Deluxe, with 4.00 x 18 rears and 4.00 x 19 fronts. Kyle adds, “although we don’t plan on racing this bike anytime soon, we can assure you all that we would change them out for a decent set of slicks if we were.”

Then the bike’s electrical system was completely redone. “We got rid of safety relays, safety switches and all the unnecessary wiring. In order to get the results we wanted, we made our own wiring harness. It gives us a clean, pain-free wiring solution and the ability to hide everything and anything we wanted.” Kyle then relocated the battery under the swing arm, in-between the center stand mounts. It’s held there using Thirteen’s custom-made battery box.

“Coming from a racing background, most of our bikes are heavily race inspired,” says Kyle. And as this is one of the only painted bikes to come out of our shop, we’re very happy with the results. We knew that we wanted to feature some sort of race-themed graphic, hence the meatball number. As for the painting process, we started off by laying down a couple of coats of base black, then placing our graphics which were cut from a special 3M vinyl. The tank and seat were hit with 4 to 6 coats of clear, then sanded and polished to give it that glass-like finish.”

And what did all this hard work create? “We are left with a bike that is a straight-up amazing ride. Its smooth power delivery from top to bottom is proof of the great engineering that went into these XJ motors.” And the modern front allows this bike to corner with perfection, soaking up all the little stuff yet stiff enough to glue the front tire to the ground. Kyle assures us that the mufflers gives off a truly sweet exhaust note that’s toffee crisp at the slightest crack of the throttle. It’s a combination that makes this XJ550 SECA an all-round brilliant bike to ride.

“We love building bikes like this and it’s refreshing to get away from the Hondas now and then,” says Kyle. “From the initial concept to the first test ride, it’s the endlessly fascinating process of creating that keeps us going. The motorcycle community is as unique as the bikes it yields, however we all share a common thread; a passion for two wheels.”