How do you set the timing on a trx250ex?

To set the timing on a TRX250EX, first ensure the engine is cool and remove the spark plug for easier access. Rotate the engine to Top Dead Center (TDC) on the compression stroke, aligning the timing mark on the flywheel with the mark on the case. Adjust the timing by loosening the timing chain tensioner and repositioning the camshaft as needed, then re-tighten the tensioner. Finally, double-check the alignment and reassemble any components before testing the engine.