The Top Dead Center (TDC) timing mark is located on the left side of the cylinder head, just above the spark plug. It is a small dot or line that is aligned with the pointer on the flywheel when the piston is at the top of its compression stroke.
Camshaft Timing Mark
The camshaft timing mark is located on the right side of the cylinder head, just below the cam chain tensioner. It is a small dot or line that is aligned with the pointer on the camshaft sprocket when the camshaft is in the correct position.
Ignition Timing Mark
The ignition timing mark is located on the left side of the flywheel, just below the TDC timing mark. It is a small dot or line that is aligned with the pointer on the stator when the ignition is set correctly.
How to Use the Timing Marks
To use the timing marks, you will need a spark plug wrench and a flat-head screwdriver.
1. Remove the spark plug.
2. Insert the flat-head screwdriver into the spark plug hole and turn the engine over until the piston is at the top of its compression stroke.
3. Align the TDC timing mark on the cylinder head with the pointer on the flywheel.
4. Install the spark plug.
5. Turn the engine over until the camshaft timing mark on the cylinder head is aligned with the pointer on the camshaft sprocket.
6. Tighten the cam chain tensioner.
7. Turn the engine over until the ignition timing mark on the flywheel is aligned with the pointer on the stator.
8. Tighten the stator bolts.
Note: The timing marks on some Yamaha TTR250 models may be located in different locations. Consult your motorcycle's service manual for specific instructions.
