Life has gotten busy for me lately, the garage projects, and blog, have both been suffering. However the lack of bike building and metal work has been exchanged for other things that are necessary to maintain a healthy and balanced life. Christmas time is busy and unfortunately many of life’s needs cannot be fixed by welding or machining. Anyway…hopefully January will provide me with cleared schedule that will allow for a bit more metal in my life.
With the CB160 engine rebuilt it was time to turn my attention onto the remainder of the bike. There is much to accomplish with the entire bike requiring rebuilding and it was time to take a serious look and what is the procedurally correct approach to take. A job well planned is a job half done so I figured I would cut my work down 50% by giving the tasks at hand some serious thought.
Whenever people are faced with a “restoration” project the initial reaction is to start ripping and tearing into it. I had the same urge but then decided to slow it down a bit. I wanted to get the frame stripped down and start to detab it, clean it and modify it. The issue came in that modifications are dependent on many factors. New exhaust requires proper clearances, seats and foot pegs require proper positioning, and modified handlebars require proper placement. All of these things will be very difficult to place once the bike is stripped down to nothing.
So I decided to start the project backwards. Before I strip everything apart for cleaning and rebuilding I decided to make my modifications first while the bike is still intact. Riding position is crucial and, as I learned, there where sacrifices to be made. I’m converting the bike to a cafe racer therefore many of the existing components are going to get removed from the bike and the riding position will be getting modified. I suspect there are many complexities involved in engineering the correct position to ride in for both performance and comfort. Certain angles work and certain do not. When moving the foot pegs I am concerned that the leverage involved in shifting and braking stay within realistic, and comfortable, positions. Handlebar placement is important to ensure that not too much of the body weight is uncomfortably supported by the arms.
So what it came down to was a lot of time spent staring at the bike and reverse engineering the frame geometry tying to teach myself what the people who built the bike were professionally taught. I had a certain image in my head of very specific things that I wanted to incorporate however experimentation would show that what I wanted and what was practical were two different things. I like the look of short, stubby, cowl style cafe racer seats. Well base on my own observations it would appear that these seats only work for bikes with long fuel tanks. In the case of the CB160 the tank is “average” and certainly not long. Installing a short seat on a bike with a short tank compresses the riding position to the point of major discomfort. My policy has always been “function over fashion” or “function first” so as much as I wanted a stubby seat the fact is that the bike would be too uncomfortable to ride.
So it came down to addressing three main factors. The handlebar position, the seating position, and the foot peg position. I knew that I would be running clubman, or clip on, style bars so I unbolted the original bars, flipped them 180 degrees, and turned them 180 degrees to simulate the new bars best as possible. The new foot pegs will be placed very close to where the rear pegs already are so this was a no brainer, I just used the rear pegs. Next was the seat, I really struggled with this one. I debated building my own cowl style seat. It would be a major learning experience for me, which I welcome, since I have very little experience with sheet metal shaping. I have much respect for those individuals how can shrink, stretch, shape, and “feel” sheet metal however my lack of experience has me second guessing myself. Perhaps building a cowl style seat may be a bit too ambitious for my first project. So I opted to purchase a fibreglass seat. After much internet research I decided to do business with Glass From The Past as many of their products are geared towards the CB160.
I spent way too much time on the GFTP website reviewing all the seat dimensions trying to determine what would work. Well after doing lots of measuring it came down to having to build a mock up seat and actually trying it out too see if the angle and dimensions would suit my riding position. So I build a seat, based on a GFTP seat, out of scrap plywood and 2x4s. With the handlebars flipped, the rear foot pegs installed and the tester wooden seat installed I was able to actually sit on the bike and get a feel for the riding position. This is where I discovered that a stubby seat will not work. The riding position was way too cramped. The bike would be rideable but it would not be fun, nor would it feel as though the rider was tuned with the rest of the mechanics. So I built a mock up seat based on dimensions that were not my first choice but where more suited to the existing bike geometry. Well it turns out that a longer seat was the way to go, the angles were great. I had my brother, who rides a GSXR1000, try out the seating position and he described it very close as the feel of his Suzuki. The longer seat with the dropped clubman bars and the rear mounted foot pegs seemed to suit a great, and comfortable, riding position; the angles are sporty and feel fantastic.
So with the geometry figured out it was time to start ordering up some parts. Foot pegs, bars, and a seat were on the list. My plan was to start performing the frame modifications before stripping everything down. Again, my parts research led me to a few suppliers. The first one being Motobits which is a company that manufactures rear sets specifically designed for racing application CB160s. The quality looks good and the option of having full adjustability is more than enough reason to make a purchase. Ordered! The handlebars where a challenge. Originally I had my heart set on a set of clip on bars but as I looked at more images and performed more research I decided that a set of clubman bars form Lossa Engineering was the way to go. Lossa Engineering has built multiple CB160s with the clubman bars so I knew they would work for my application. The final purchase was made from Glass From The Past where I ordered their VINBTB seat. I am not completely comfortable with the way the seat cowl angles up as I really like the lines created by a straight base however life is comprised of comprises.
So at this point in time I have received the rear sets from Motobits and the clubman bars from Lossa Engineering. The design and quality of both products are great, no complaints and nothing but positive comments. The seat will take awhile before I see it since I opted to splurge for the optional leather upholstery. Anyway…t he geometry all seem to be coming together which puts me one step closer to turning bolts counter clockwise and applying 120psi to a bag of sand.