The two stroke dirt bike community simmered out for a while, but just like the mullet, it's back in style and all the cool kids have one. With 2-stroke only races popping up, I decided I was tired of missing out on the action and it was time for some throwback fun. I had my heart set on a YZ 125 and the hunt was on.
The COVID pandemic put a wrench in my plans for a while. The bike market was hot, and 2-strokes were gold. Lucky for me, I struck gold on a Wednesday night when I found a 2019 with low hours in southern California. Four hours later I was disturbing the peace as I took the bike for a test ride under the glow of the street lights. One Venmo exchange later and we were back on our way home. This is where I have to thank my amazing husband for the down and back trip on a work night night.
After having the bike home for a week, I started to think of what it could be. The only thing standing between me and my vision was my husband. I had to make him understand this new necessity. Since he loves me...and happy wife happy life...convincing my husband wasn't too difficult. Two weeks after bringing her home, we were headed back to So. Cal for a trip to Twisted Development. Jamie Ellis and the TD team are famous for their powerhouse 4-strokes that you will regularly see lining up for the Monster Energy Supercross, but they also build bikes for the average Joe and were named #1 Engine Service in the 2021 Vital MX Audience Survey to prove it.
My first experience with Twisted was after buying a used yz250f race bike. After opening the motor for the first rebuild, we found that the part numbers on the high compression piston corresponded to a custom piston made specifically for the bike by TD. We thought for sure it was time to breakout the credit card. TD had a piston in the mail to us the next day for the same price as a standard piston. Not only were we shocked by the reasonable price, but the mechanic spent the time to provide a few tips and tricks over the phone. The level of customer care we experienced from a world class shop to DIY mechanics was far beyond our expectations. From there on, we've used them for ECU tunes, valve seat cutting and part purchases. The 125 build was our first opportunity to see the magic first hand.
We outlined the goal of the project to produce a motor with a smooth powerband built with reliability in mind for long GP Races. With technique training still in mind, we didn't want to stray too far from the stock bore. The Twisted crew elected to go the "Big Bore" 144cc route with VP's T2 as the fuel of choice. The motor was rebuilt from the bottom up.
Starting with crank, the stock plastic crank stuffers were removed and replaced with aluminum stuffers which will not melt under extreme heat. Another downfall to plastic is that it acts as a insulator where as aluminum acts as a heat sink and pulls heat away from the bearings and crank allowing it to be transferred to the incoming air/fuel. The crark then underwent an "Atomization Surface Treatment." This process roughens the surface of the crank which creates turbulence in the crank case resulting in better fuel atomization and more power. To finish it off, it was then balanced to cut down on the beasts vibration.
Topped with ported and polished Athena 144 cylinder head, Vforce 3 reeds and dyno tuned by the talented Jim Braho, the stock clutch was no match for the new power. We elected to use a Hinson Billetproof Clutch which has been my go to clutch over the years. Finally, the sweet smell of VP is exhausted through and FMF Fatty Pipe and Powercore 2 shorty silencer.
One of the best ways to gain more ponies is to free up horse power by reducing friction. The transmission gears underwent an isotropic transmission service to reduce friction, improve oil flow, reduce heat generation and cause less wear. TM Designs chain slide, guide and rollers were paired with Mika metal chain and sprocket for a smooth drive train.
With the power plant sorted out, it was time to focus on handling. In stock form, the suspension left a lot to be desired. Factory Connection was my first call. They have the data from testing to make sure the bike is sprung and valved properly for your weight and ability. They offer trackside support days at tracks around the country, and the phone support is amazing. They'll help you get the clickers dialed just right. The FC tuned forks and shock were paired with a GPR stabilizer to eliminate the possibility of head shake. Not only does the GPR keep the front wheel pointed where I want it, but the rubber bar mounts do wonders to cut down on that famous two stoke vibrations that us young guns aren't built for. I bow down to the 250cc & 500cc riders from back in the day!
Overall, I'm thrilled with the end result. Simply put, this bike is just plain fun to ride. There's something about ripping the throttle of the old two stroke technology that just makes you feel cooler than you are. I want to say a sincere thank you to the team below. These companies have provided so much support for myself and many other riders over the years.
Hoosier Tires West
Race Gas Supplements
All Balls Racing