Recently I found a cosmetically rough, but good running XT225 for a pretty reasonable price. A friend of mine has been wanting to upgrade his TW, so I had him ride the XT to see if the engine felt good to him. He liked it, so I swapped it over for him, and the result is fantastic! It feels like more than a 25cc upgrade, and I definitely think it was a worthwhile project.
The key is finding the right donor bike... the more complete, the better. Being able to ride it before tearing it down is a big confidence booster. I actually did some additional work to this engine on my bench before the swap, but if you have a running engine that you're comfortable with, then the swap itself is pretty straight forward.
First things first, I had to get both engines out of the bikes, and on my bench. The TW engine is on the left, and the XT engine is on the right. You may notice the XT has deeper cooling fins on the cylinder, creating more of a square profile... this causes a couple of issues, but nothing insurmountable.
Next, I pulled the side covers off. To get the XT engine to work with the TW electrical system, the TW flywheel needs to be mounted to the XT engine, along with the TW side cover (after a few changes).
Here's the tool for removing the flywheels. It's just a bolt, really, but it does the job nicely with an electric impact driver.
Here, both flywheels have been removed, and the TW flywheel has been installed on the XT engine.
Next, I'll work on the TW side cover.
The key is finding the right donor bike... the more complete, the better. Being able to ride it before tearing it down is a big confidence booster. I actually did some additional work to this engine on my bench before the swap, but if you have a running engine that you're comfortable with, then the swap itself is pretty straight forward.
First things first, I had to get both engines out of the bikes, and on my bench. The TW engine is on the left, and the XT engine is on the right. You may notice the XT has deeper cooling fins on the cylinder, creating more of a square profile... this causes a couple of issues, but nothing insurmountable.
Next, I pulled the side covers off. To get the XT engine to work with the TW electrical system, the TW flywheel needs to be mounted to the XT engine, along with the TW side cover (after a few changes).
Here's the tool for removing the flywheels. It's just a bolt, really, but it does the job nicely with an electric impact driver.
Here, both flywheels have been removed, and the TW flywheel has been installed on the XT engine.
Next, I'll work on the TW side cover.