Navigation Tower Honda CRF 250L

Daan Design Navigation Tower for the Honda CRF 250L

250L adventure Bike CRF Custom Honda motorcycle navigation Navigation Tower tet

In the last Honda CRF 250L project I improved the carrying capacity by designing a custom luggage rack. After the last trip on the Trans European Trail (TET) in France I noticed that more wind protection was needed in order to be less fatigued on long liaisons. Also missing was a better solution for mounting navigation devices and better lights. This is how the idea came to mind to transform the Honda CRF 250L into an even better adventure bike. To achieve this I decided to design a navigation tower that would answer to the following demands:

- Durable enough to take multiple crashes

- Easily reparable

- Light weight

- Overall size is small so the view from cockpit isn’t hindered

- Practical, Functional, Simple design

- The GPS mounting point must be easily adapted in angle

- Everything must be street legal

- It must have the looks of a rally bike

- It must hold: USB Outlet & 12V Socket; Handheld GPS; Garmin Zumo XT; 2 Auxiliary Lights; Wind Shield; RAM mounts, Go Pro and Smartphone.

First I researched what navigation towers are available for the Honda CRF 250L. It turns out there aren't a lot of options to choose from.
I found some home-made solutions with custom made fairings made out of fiberglass. Although they are cool projects, I didn't like the look and they are very labor intensive. I wanted something more robust, better quality finish and better looking. The white crf250L was more the look I was going for with a clear windshield.

The best navigation tower I could find for the crf 250L was this navigation tower from Touareg Aventures, designed by Patrick Trahan. The tower is very strong and does the job very well. However I didn't like the fact you have to move the ignition switch on the tower because the tower is attached on the frame. This means you can't lock the handlebars. This tower also reuses the OEM signaling lights which brake easily and are very bulky. The tower itself looks bulky on the bike and doesn't fit with the design language of the bike. Overall I like the look they are going for and it is a functional heavy duty piece of kit.

Also a good solution is from Adventure Spec. With this mini fairing they managed to create a very minimalistic solution yet still answer to customer needs. It doesn't require drilling or compromising the bikes functionality. It bolts on and gives you the added value of better wind protection and mounting options for GPS devices and usb-chargers. However the wind protection could be improved and the lighting hasn't changed.

This is a fairing from Lynx Fairings. It does what it needs to do. However the installation is intrusive, you have to cut into your front fender in order to fit the plastics. I don't like this at all what if you want to sell the bike later or you want to go back to the OEM bike?

I made two graphs to show witch gap in the market my Daan Design CRF 250 L Navigation Tower fills in. One graph shows the ease of installation and the other how well the different products answer to the customer needs of an adventure rider.
In short I can say that my design is not nearly as expensive as the race oriented rally towers on the market even more it looks and performs almost at the same level as the most expensive rally kits on the market.

The first thing that I did was to measure and 3D model the important parts on the motorbike that I will be using to mount the tower on.
I decided early on that a tower attached to the frame would be hard to achieve with the ignition switch being in the way when turning the handle bar.
I decided to go for a tower that mounts on the triple clamps and turns with the forks. The advantages of this is that you will shine light in the direction you are turning.
It was an experiment to see if wind and the weight of the tower wouldn't have any negative effect on the handling characteristics of the bike. And I can tell that after testing the feeling with the navigation tower on is just the same as having the OEM parts attached to the triple clamps.

Next I started sketching and laying out the different devices how I want them to be presented in front of the rider. Here you can see the evolution from the stock bike to the finished design.

Every part on the tower has under gone several steps. First step was to make a cardboard template of the part that fits on the bike to get the right shape and basic measurements from the bike into the 3D modeling software.
Rarely do you get things right from the first try so the second step was to go back and forth between the computer then printing out an accurate scale 1:1 technical drawing and to cut out the exact shape in cardboard until every part fits well and looks esthetically pleasing.
When I was happy with the result I made the part out of wood to have more strength in the model, to be able to test ride it and fit all the parts to the tower.

The brackets that form the connection between the tower and the bike have gone through simulation tests to predict how effective the part will be under load.

After a lot of work the 3D model design was done and this is the final result.

Next step was to produce this part. So we prepared the technical drawings for all the parts. This included, measurements for every part, flat patterns of parts that had to be bend and assembly drawings. These were sent to the company that would laser cut, bend and annodize the parts for us.

Meanwhile that the production was underway we upgraded the stock electric connection for the headlights to a waterproof connector. The new headlights are LED from the brand LSK Electronics. XH1 is the name of the headlights they have position lights, low and high beam.

In the end the navigation tower without anything attached to it weighs in at 1830gr (with all the parts attached to the tower it will probably weigh in around 3000gr (educated guess)). This is only a 84gr increase compared to the 1746gr of the stock headlight unit.