I recently bought a 2002 Honda Shadow VLX. I did this because (1) I needed a vehicle in my new, public transitless town, (2) said town has above-freezing temperatures year-round, and (3) because I’ve always wanted a motorcycle. Needless to say, I’ve had a lot of fun tooling around on my hog. I recently went on a longish (1.5 hours one way) trip and I wanted to be able to rest my throttle hand occasionally along the way. I had heard of throttle locks and a quick search on the Google yielded hundreds of results, most of which had a similar design: a bar that grips the throttle and gets pinned against the brake lever, thus holding the throttle in place. I even found a few on Thingiverse. This was such a simple design, I was sure I could make one on my Bantam Tools CNC Machine.
I sketched up three or four waaaay overcomplicated and overengineered designs before I settled on this one:
I took inspiration from (read: copied) the photos I saw whilst googling. In my research, I also read that this throttle lock design can be difficult to position with one hand, so I added a thumb tab to make adjusting a little easier. With everything modeled out, I went to CAM. Using the HDPE tool library I created last month, I set up a simple 2D Contour operation and posted it out.
The First Cut is the Deepest
I added the spoil board when I set up my mill, but forgot to re-locate my tool. The first cut ended with a terrible crunching sound as the machine sent the end mill into the spoil board it didn’t think was there. :grimacing: Luckily, I had fast reflexes and the end mill wasn’t damaged. Lesson learned: any time the spoil board height changes, re-locate the tool.
Once I had recovered emotionally, zeroed the machine, and located the tool, I ran the job again and five minutes later I had an ok-looking throttle lock. I don’t think the plastic I used was actually HDPE. I honestly don’t know what it was, since I got it out of an unlabeled scrap pile. It had a similar density, but left quite a few stringies on the top edge of the cut. On the plus side, the profile totally looks like a jalapeño pepper!
A little work with some sandpaper and a craft knife took care of the stringing and I took my creation out to the bike for a test fit.
This never happens, but I got the fit right on the first try! The diamond is just a little smaller than the handlebar and the natural flex of the material holds it tight enough to lock the throttle, but not so tight I couldn’t disengage it when I needed to—a must for safe riding.
On the trip it worked flawlessly, allowing me to keep my hand on the handlebar, but relax my grip on the throttle. It made the ride that much more comfortable and less tiring and I would definitely use it again for long highway stretches.
I’ve included a link to the file below. You can download it as an STL for 3D printing or DXF for CAD/CAM.
Disclaimer: In providing these files, I take no responsibility for their final use, safety, or legality. Please check your local regulations about using this modification on a motorcycle, be safe, and, for heaven’s sake, wear a helmet!
Be safe, have fun, and please drop me a line if you have any questions or comments!