2025 graduates

As part of our research, we completed a comparison between a gas powered Yamaha YZ250F and our modified Electric version to determine if it is feasible to create a bike comparable to NYOA and AMA standards. 

Before beginning our transition to fully electric, we completed some testing on the combustion powered bike to create a comparison between the two systems. Examples of tests completed include acceleration and top speed over a specific distance.

While waiting for our battery and motor kit to arrive, the bike was completely gutted of anything that wouldn't be utilized in our conversion process, inlcuding removing the initial gas-powered motor which was found to be blown on this chassis.

Once stripped of any unnecessary parts, we cleaned and polished the frame to restore it a little bit.

Once the frame was cleaned up and polished a little bit, we began applying the custom wrap to our new plastics purchased for the bike, still have to apply some wraps but making good progress in meeting our research forum deadline.

After our electric kit arrived, we began the process of slightly modifying the bike frame as there were some brackets that need to be removed. This area would be where the battery and motor would be housed within the frame.

Once our frame was modified, we completed the installation of the new QS138 electrical motor, 76V battery, standard controller, charging system, battery monitoring system (BMS), and new throttle system and its connections. All wires were run so there were no pinch points causing issues with connections. We also wanted to make sure the wiring was done cleanly for ease of access when making changes to the system in the future.

Due to real-world constraints, we were unable to receive the controller we ordered for us to adjust outputs to motor. Unfortunately, we were unable to complete the same testing on our converted bike to determine which settings would be efficient and close to the performance of a combustion bike approved to compete in AMA sanctioned events. The controller we ended up receiving is an EM-260S controller that needed a bracket created to mount it to the bike.

Our System analysis subgroup designed a bracket prototype on SolidWorks and completed a steady state thermal analysis on Ansys to determine which material would be best for our bracket. Materials considered include Aluminum and Stainless Steel. Not only does the bracket serve as a way to mount the controller to the bike, but as a source of heat dissipation for the controller as well. Our design parameters are as follows:

• Length - 8.50 inches
• Width - 6.00 inches
• Thickness - 0.60 inches
• Fillet Radius - 0.25 inches
• Screw Holes - 0.1425 inches

Based on our thermal simulation results, we determined that aluminum would be the better material. Aluminum has a higher heat flux range which allows for more heat to dissipated as well as lower temperature as well which will help with keeping our systems cool. It also has a higher thermal conductivity value than stainless steel which makes it the better option for our design. Unfortunately, due to time constraints we were unable to fully manufacture our bracket at this time.

Once our system was completed wired and installed, we just need to modify the area where our seat would mount to the bike. The set typically mounts to the gas tank, which had no room to be installed due to the height of the battery casing. To ensure our seat could be installed, we cut our gas tank in half and shaped the remaining pieces to fit around the battery to allow for our seat to be mounted.

After installing our seat, our plastics were attached to the bike to fully complete our conversion of the bike. Our plan over the next few weeks is to complete a side-by-side comparison between the combustion powered bike, allowing us to complete our official testing results.