Fork Installation on Cafe Racer K1100SX
Finally, all parts of the fork are ready, and we can install it and look at the motorcycle ready to go. The fork is one of the most difficult parts of a motorcycle, it must have suitable characteristics and a complete factory look. Due to the installation of new wheels and modification of the frame, the feathers had to be shortened, and we had to change the parameters of the steering tube because of the type change of the motorcycle from tourist to urban. At the same time, we had to make a bunch of custom parts, so that everything would match and look good. Down below you can read about each part separately, about difficulties which we had to face, and about nuances which need to be considered while building this motorcycle.
We have separate videos and an article about shortening the fork, where we explained how to adapt it to the spoke wheel. We recommend to wrap the jars after assembly into something to protect the surface, since it is easy to damage it during the assembly process. We also had to order new fasteners and new end caps, because the old ones spoiled the way handlebar looked.
Stock triple clamps are not suitable because of the geometry and bulky appearance: they have a big offset and the upper triple clamp is too thick, which overloads the handlebar. For a city motorcycle, the offset should be smaller - this will worsen its stability on a straight line, but it will create a quicker response to counter steering for easier tilting and quick maneuvers, which is more important in the city. We reduced the offset by 4 mm. This should be considered when calculating the length of the fork and the choice of tires. It is better to install an adjustable rear shock absorber, as it will allow to compensate for errors in the calculations. Also, a decrease in steering offset may require the installation of a steering damper - this will be clear after the test rides.
In the triple clamp making process, we recommend to consider all the technological holes and the seating places for the hinge. We decided to put the Motosign Mini alarm panel and Motogadget dashboard in aluminum cases. It is better to use the most durable alloy B95T. The upper triple clamp should not be made thick - the steering will become less elegant, and the clip-ons will be too low. We will also replace the nut and the stopper head with the new ones in the final assembly.
If you want to modify the frame, tank, steering tube, wheels, and driver footpegs, then it makes sense to mount adjustable clip-ons. It is very difficult to model a seating position at the design stage, so if you use adjustable clip-ons, it will make it easy to tune the motorcycle for the rider without alterations. It is better not to save on clip-ons. We chose the German ABM adjustable clip-ons, because they are fully adjustable, well made and look good.
It’s impossible to buy 41.7 mm clip-ons, so you’ll have to cut the 41 mm ones.
Headlight and mount
Since we went to an aluminum milling with an anodized coating, mounting the LSL headlight was the best solution. We chose the headlights mounts with a length of 82 mm and holes for the turn signals. The length of 82 mm matches well with the LSL EIGHTIES headlamp, because it has a relatively short body. The fastening length is 97 mm and it fits better to the classic drop-shaped headlights. Clamps must be cut to 41.7 mm like everything else. When choosing a headlights mount, you should take vibrations into account. The BMW K1100LT is a tourist motorcycle with a non-rigid frame mount and a low-vibration engine, so a rigid headlight mount is fine!
It is better to assemble everything according to the manual. The BMW K1100LT is a rather complicated motorcycle, so the experience gained on modern motorcycles is not always useful.
We hope our experience is useful to someone, and that it is as interesting for the viewers to follow the project as it is for us to carry it out!