Project overview
Motorcycles are known to have ugly looking stock rear fenders due to different safety laws. Recently bought myself a 2022 Honda CRF 300L and it was no exception. This post covers how I manufactured my own blockoff plate and plate mounting for the bike, as well as functions as a kind of guide on how to do your own. Links can be found below for the STL-files.
The project started by modeling the rough shape of the plate in Blender. I made a couple of test prints until I managed to get the desired shape and thickness. The design uses the stock rubber mounts (Parts #12 and #3) that come with the stock taillight assembly. I added small countersunk spots for them and made the holes roughly 5% larger in diameter to accommodate for plastic shrinkage and tolerance issues. The main downside with this part of the process was the lack of a personal garage. Found storage at work for the winter season, but still had to drive around 7km’s back and forth to test the fitment. Why buy something factory made for 100$ when you can waste 40$ on materials, 60$ on gas and 140$ on unpaid wages? In the end I used less measurements and more of the SWAG-method.
“SWAG = scientific wild ass guess“
Cleaned up the model and modeled a new improved version in Siemens NX. Blender is a fantastic program that’s free to use but doesn’t produce clean models for 3D-printing. I also added small grooves for bending the print into shape. The dimensions on the sketches are rough and aren’t meant for recreation, however the top left one can be used as a printed stencil for plastic cutouts as an alternative to 3D-printing.
“Don’t measure in millimeters what will be marked with a crayon and cut with an axe”
I printed the pieces on my Creality Ender-3 V3 KE. I’ve had this printer for over a year now and have been very pleased with it’s performance. It’s not the best one out there, however it’s definitely good bang for buck and I think everyone engineering or electronics oriented should have one or similar in their home or garage. The current model was printed in PLA, however at some point it will need to be reprinted in ABS or ASA. Despite being a good budget printer, the Ender can’t print either due to the lack of a heated enclosure. This would also add the benefit of being able to vapor smooth them for a better surface finish. Perhaps I will be build a heated chamber in the near future, as I’m already familiar with vapor smoothing.
I spent ages trying to find a light that would meet legal requirements, be visible and the correct size. None would meet all the criteria except for one sold by a local department store. (alternate link, I don’t take accountability for store credibility).(ebay) Honda has designed the electronics so well, the led doesn’t flicker even at low rpm. The taillight uses Sumitomo HX .040 3-pin connector. I robbed and re-pinned mine off of the 250L.
Light fits the blockoff plate like dad fits mom. Unlike my childhood family dynamic, I was the one getting violent and vulgar this time around.
Made the actual plate holder from scrap pieces of steel using a dremel and powdercoated them with a powdercoating gun I made myself, which is evident by the quality of the coating. Despite having enough orange peel to be found found in the produce isle, the coating proved very strong and resistant to ball hammer blows. Being textured like this honestly adds a kind of industrial look to it. The holder consists of 2 parts: Upper and lower mounts. The upper mount holds the plate and the lower one provides support against unwanted vibration and bending. Despite looking a little sketchy the mount feels solid enough to the point where I would even dare to lift the entire bike by it. This is somewhat disadvantageous in a crash, since the frame might get bent. The plate is connected using the OEM plastic piece. I used Prismatic powders Super Durable Matte Black.
Before all the professional powdercoaters come here to educate me on proper prep work, preheating, voltage and spray patterns, have a look at what I’m working with:
back to the topic
I honestly think this looks a lot better than the original. Also changed: Fatbar, mirrors, levers, pegs and shifter. Thingiverse: https://www.thingiverse.com/thing:7291282
Projects like these are kind of like making out with your cousin, you know it’s legal but it feels somewhat illegal. Laws in different countries might differ on the topic of plate placement and mounting. The light I’m using is E-approved and the angle and placement of the plate is also within requirements.
Turbojustus 