Moped Interlude

In addition to science, I love mopeds and modified a Yamaha QT50 to go way fast. Here’s the past, present, and future of my moped journey. I’m looking forward to combining mopeds, data analysis, programming, and building stuff. Cover art is me at 3 years old in my local news paper for washing my tricycle in the summer (slow day in Dodge City, KS) and a graduation picture of my moped in front of the Chemistry and Biochemistry building at Kansas State University, which is where I taught the General Chemistry Lab.

First, the why

Cuz I promised myself in 2012 when I transferred to Kansas State that I’d focus on my academic career, but as soon as I got my first industry job, I’d restore my first car: a 1986 Nissan 300zx I bought in high school ($600 ebay find!) That said, its been 10+ years of putting academic life first, and I can’t wait any longer to start living life and making mechanics my serious hobby, so I’m going to ease into things with my moped.

My 1986 Nissan 300zx back in 2010. Some details: GLL (digital dash!), 2+2, t-tops, and louvers.

QT50 and Kansas State

In 2013, I was an undergrad at K-State studying biochemistry and I decided to buy a 1984 Yamaha QT50 from some dude on craigslist cuz I missed working on my 300zx. It wasn’t running, but that never stopped me before. I was told it had a bunch of upgrades and was modded by an electrical engineering (student or professor, IDK). They wanted $600, but since they didn’t know what the issue was, I countered with $350, but they also had a literal shopping basket filled with spare parts like a driveshaft, an engine, a wheel, etc, so we settled on $475. I kind of tried to get it working, but I was an student and got busy with student things (insect genomics fellowship!), so I took it to Yamaha and asked them to check it out (turns out, the kick starter was broken). $200 in parts and labor later, I had my primary mode of transportation on campus. I also like to refer to it as La Poderosa (the powerful) cuz it is.

Mopeds are fun and they’re also hilarious. **not legal advice** Someone might get the idea that if a moped can fit, you can park it there. And that person would be mostly right: someone could park in the bike racks in front of every building, which sounds objectively amazing. However, parking a moped in a bike rack at K-State allegedly comes with a $40 ticket, which is why my moped had a motorcycle permit. Some people say that it was mostly for parking during the hours of 9am-5pm, and outside of those hours parking laws didn’t apply but I’m a scientist, not a lawyer. A moped could come in ridiculously clutch during finals, considering that Hale library gets packed during finals week so you gotta park a mile away from campus, but that’s neither here nor there. **/not legal advice**. My friends would always make fun of my moped, which only made me love it more. Besides, everyone who’s ever hated on my moped took their hate back after they rode it and admitted that it was cool so ¯\_(ツ)_/¯. One of my favorite memories: losing a race against my friend’s Nissan Maxima and immediately running out of gas. I will say that before running out of gas in the middle of the race, I was the first one off the line. Also, everyone wanted to borrow my moped for my fraternity’s fundraisers: making and delivering enchiladas and japchae (Sigma Lambda Beta; we’re multicultural).

Never lost the reup.

La Poderosa in LA

When I graduated in 2015 and was getting ready to start grad school at USC, I couldn’t take the moped to LA (figuratively and literally, the gas tank holds 0.6 gallons) so I kept it at my parent’s garage. I made a surprise visit home for Thanksgiving later that year, and since I drove, I figured it was the perfect chance to bring my moped back with me. I packed light and it fit in the trunk of my Chevy Impala, so why not? Besides, I got prior approval from the manager of my apartment complex who said I could park it near one of the gates, a super important factor to me when I was looking for apartments.

2016 was a tough year for many grad school reasons, and my moped became a dope outlet for my energy. Perhaps I went a little overboard with the mods, but your motorbike can’t be known on the street as a “Yamahopper” without being able to take off. Anyway, I bought over $600 in performance parts from treatland, and allegedly*, it could get to up to 55mph. However, the suspension was built to handle that kind of power, and neither were the brakes, so I rarely drove it. It was giving me the same feeling the 1969 Charger gave Dominic Torreto in The Fast and The Furious.

I planned to boost the acceleration with stiffer clutch springs and tune the moped properly, but when my lease ended in the summer of 2016 and with my new apartment complex having not one, but TWO a steep hills**, I had to park La poderosa in the shed behind my aunt’s house.

Bay Area chapter

Recently, my girlfriend and I celebrated her birthday with her family in LA, and I was looking for my next project, since I finished most of the sound, stereo, and appearance upgrades on my Honda Fit. I didn’t think about bringing my moped back with us until the morning of our last outing, which was going to be in Little Tokyo; not close to my aunt’s house but not a huge distance either. I arranged to pick it up, it fit in my Honda Fit (lol) and now you’re reading this.

First, I have to get it running again, but then I’m picking up right where I left off: tuning the engine to the aftermarket carburetor, intake, and exhaust. I did a preliminary analysis of the internals, and things look good. Unfortunately, I lost the shopping basket full of extra parts (left it in a storage lab at USC, which was cleared out/thrown away when I was in Chicago doing my brain slice sabbatical). The K&N air filter also got lost while in storage, but it’s easy enough to get running again: I already ordered the missing parts from Treats to get it running, and have even bigger plans to customize it.

The most interesting side side-project I thought about is a low-cost temperature monitoring system. I bought this trailtech kit back in 2016, but the battery isn’t removable, so it’s basically a single-use part, a luxury in the moped community at $60! I looked into it, and found a temperature sensor (thermocouple) and a digital gauge on amazon, which can help me monitor the engine temperature when I’m riding, but it’s not the most scientific solution for data-driven tuning, since you aren’t logging the data. I guess you could record the temp changes with an old/spare camera phone mounted in front of the gauge, but that only gives you a max temp, and will hamper the riding experience.

I thought about building something using DATAQ instruments (see my post on digitizing two electrode voltage clamp recordings), but in the context of the moped lyfe, its expensive and impractical, since you need to a laptop to run the instrument (and you’d need a big basket and a lot of zipties). Then I remembered my original plan to build a low-cost analog to digital converter in grad school, which was to log the data using an Arduino and RaspberryPi computer. I didn’t go that route because a cheap laptop wired to a DATAQ digitizer worked quickly, easily and cheaply, but I still had the CrowPi kit and the RaspberryPi touchscreen interface I was playing with, so I thought: why not use a RaspberryPi and Arduino to log the cylinder head temperature data while I’m tuning the carburetor and run analysis offline? Each device is small enough that it can fit in the basket or the cargo rack of my moped, and an external battery was easy enough to find. Sure enough, I found a board that can connect to the thermocouple on Amazon, so now I just have to put it all together and optimize!

Anyway, that’s what I’m up to in my spare time. I’ll post updates as things develop, and you can see a more complete parts list of the build on this spreadsheet. If you have any thoughts, leave them in the comments!

* depends on if you trust the speed filter on SC

** hills are the one moped weakness that I’m aware of