Turbo Yamaha MT10

This one is for the speed nuts.

At Purpose Built Moto, there's always something interesting in the works, and the latest project to roll out of the garage is no exception. The team recently finished an MT10 that came in for some serious work after a turbo install led to a blown motor.

Our story begins with a Yamaha MT10; a bike that can already happily reach speeds to help you meet your maker. This one was a bit different, it had been fitted with an Extreme Creations turbo kit that, in a bid to break the sound barrier, ended up blowing the motor apart. Our aim was clear from the start, to not only repair the MT10 but to make the bike faster and to do it more reliably.

The heart of the MT10 is highly strung to begin with, running a compression ratio of 12 to 1. The turbo kit from Extreme Creations, was designed to easily fit the bike and run at 7PSI. However, Cassidy, the owner, took a liking to the boost tap, and wound it up, over-boosting the engine to the point of hand-grenading. The evidence lay internally and on tear down, the engine was marked by holes in 3 out of the 4 pistons and serious signs of overheating.

The repair and upgrade process began with Jesse, our resident performance expert, making a full assessment of what may have contributed to the motors detonation. He noticed the charge piping running dangerously close to the exhaust, a design flaw that likely led to hot air being dumped directly into the engine. This was just the tip of the iceberg. Turbo engines typically do not run a 12 to 1 compression ratio, so that had to change too.

We repositioned the intake away from the headers and under the seat to prevent overheating. Additionally, at Cassidy's request, we replaced the turbo's internal wastegate with an external Go Fast Bits EX38 which led to some tricky engineering.

The wastegate plumbing is a dual setup. One part served as a dump-to-atmosphere pipe, while the other could be plumbed back into the muffler — a design choice that meant the bike could be easily adjusted for legal compliance. This setup, incorporating a few mounts and clamps, will allow Cassidy to switch setups if he ever runs into compliance trouble.

At this point Dylan stepped up with his fabrication skills. Cassidy had installed a swing arm extension kit that opened up a bit of space for Dylan to tuck a large DNA pod filter neatly underneath the tail. The fabrication of a three-inch charge pipe out of pie cuts, was not just a style statement. It played a crucial functional role, moving the standard intake from underneath the chain, where it was vulnerable to debris and hot air, to a safer and more efficient position. The air going in will be much cooler and it'll be less likely to suck up contaminants, crucial for the performance of the engine. But dang, it looks good.

Recognizing the need for a more robust cooling solution, we reached out to PWR Performance, specialists in high-performance intercoolers and cooling systems and their expertise proved invaluable. We wanted to ensure the intake plenum was getting cool air considering the turbo's proximity to the engine's header pipes. PWR Performance helped us out by building a custom intercooler tested on the specific angle it would be mounted, and then iterated it with a fan setup for our specific requirements. This cooler meant that the MT10 could stay cool even in stop-and-go traffic.

The important bits of this project were in the engine overhaul. Jesse pulled it down, identifying and addressing its weaknesses. This resulted in a collaboration with CP Pistons who ended up designing and building custom pistons that reduced the compression ratio to a more turbo-friendly 9.5 to 1. Alongside this, due to the stock the con rods being quite light, CP’s were installed in their place to support the increased power and boost levels.

With the rebuild complete, it was time to put the MT10 to the test. Jaime from Dynamite Motors, a trusted partner for our tuning needs, was eager to see what this beast could do. On the dyno, the MT10 made 230 horsepower at around 10 PSI. But the surprises didn't end there. The Delkovic exhaust the bike was fitted with had quite a substantial baffle in it which upon removal, and without any additional tuning, caused the power to shoot up to 260 horsepower. In consideration of Cassidy's needs and desire to keep his hearing intact, we decided to slightly detune the bike, for now. Should Cassidy crave more power, there's room to grow. By freeing up the exhaust flow and readjusting the tune, we can unlock quite a bit more.

As we close the chapter on the MT10 turbo project, it stands as a testament to Purpose Built Moto's dedication to pushing boundaries to constantly learn more about custom motorcycle building. For those keen on following the MT10's future adventures, be sure to check out @CassidyGlyde on Instagram.