Chain Tensioner Installation Instructions
1. On some models including the 250/350 motors, it is necessary to put the engine at TDC before proceeding. Check your owner’s manual.
2. Remove the outer Cover Plug and Small O-Ring.
3. Remove the large Cover Bolt with Copper Washer. (Note: It is recommended to pay attention to the direction of the Copper Washer to ensure it is replaced the same way. This will help it reseal).
4. Using a magnet (or being very careful with pliers). Grab the end of the OEM Tensioner and pull it outward. Be careful not to damage the aluminum port or face.
5. If the O-Ring did not come out with the OEM Tensioner, carefully reach into the port and remove it without pushing it further into the engine. You will need to reuse this O-Ring with the DT Tensioner.
INSTALL DIRT TRICKS CHAIN TENSIONER
1. To prepare the DT Tensioner, set the spring aside, and make sure it is in the collapsed position. (They are packaged and shipped in the collapsed position). If you have accidentally extended it, gravity will usually return it to fully collapsed by pointing it upward. If it has locked into place, rotate the assembly until the word “Top” on the piston is facing up. Then a light tap from the bottom will release the ratchet. This will now allow the plunger to be retracted to about 1-13/16” (46mm) which is fully collapsed.
2. Install the O-Ring over the outward side of the DT Tensioner body, keeping it outboard of the ridge as shown above.
3. Slide the fully collapsed DT Tensioner assembly with O-Ring (without the spring), into the Engine Port. The end (with the Hex-Head Spring Hole) should only protrude from the engine about 1/32” (.75mm). This measurement will be greater if installing part number TC-2 in a 350 motor.
4. Install the Cover Bolt and tighten. The Copper Washer should be tight. (Note: “Top” does not need to be upward for installation).
5. Insert the spring through the hole in the Cover Bolt. As it is slowly inserted, you may hear clicks as it pushes the plunger forward.
6. Install and tighten the Plug against the Spring. (Note: some 250 engines have a one piece cap. Slide the Spring into the DT Tensioner just far enough to hold it, then capture it with the cap and tighten).
7. Start the engine and carefully check for oil leaks. Adjustment will occur internally as it is needed. No further maintenance of the DT Tensioner is required.
Husaberg requires special attention during installation. The Tensioner rests vertical on the Husaberg. Since gravity will extend this part, you must find a way to ensure it remains collapsed. You need to orientate the Tensioner Port in a horizontal position to allow installation in the collapsed position. Laying the bike over on its side should work. It may be helpful to place something under your wheels as well. The goal is to orientate the Tensioner Port horizontal to the ground so the Tensioner will remain collapsed during installation.
PLEASE READ BEFORE INSTALLATION
Do not install on a brand new motor. Installation of part TC-2 should only occur after a minimum break in period of approximately 20 hours on a brand new 350 motor. This is also true for some newer model KTMs using part TCT. A modification to the OEM Tensioner has been made; it will collapse nearly flush within itself. In this fully collapsed position, the OEM Tensioner is shorter than the DT Tensioner. If you perform the install on a brand new motor, the extra length may apply too much tension to your timing chain guide. This may produce premature wear to your guide.
How do you know that you have put enough time on your motor for a safe install? The 20 hour mark we have established should be more than plenty, but you can compare the two side by side as well. Remove the OEM Tensioner from your motor and compare the overall length from the last running position with the collapsed DT Tensioner. If it is equal to, or longer than the fully collapsed DT Tensioner you are safe to perform the installation. We have tested multiple 250, 350, and 450 engines starting brand new from 0 hours. Once you achieve 20 hours, installation should be safe for any model. To access the Tensioner on some models, you will most likely need to remove your lower right side Radiator Hose. This will allow just enough room to perform the installation.
Note: All model 250/350’s run the risk of jumping time from the removal of the OEM Tensioner. Setting your motor to TDC and using the OEM crank locating screw before you begin installation will prevent this and is highly recommended. Follow the procedure in your owner’s manual or consult your local KTM shop for help. It is also recommended to verify your motor is on time before and after installation