KTM 250F Timing Chain Tensioner Installation Instructions


Filed Under (KTM) by admin on 19-10-2010

1) Remove OEM Tensioner: On some models including the 250F motors, it may be necessary to put the engine at TDC before proceeding. Check your manual. This is not the case on the 450 and 530 single cam motors. • Remove the outer cover plug. • Remove the large cover with copper washer. • Using needle nose pliers grab the end of the OEM tensioner and pull it outward. Be careful not to damage the aluminum port or face. • If the O-ring did not come out with the tensioner, carefully reach into the port and remove it without pushing it further into the engine. 2) Install new Tensioner: • To prepare the new tensioner, set the spring aside. Put the new tensioner in the collapsed position. (They are packaged and shipped in the collapsed position.) If you have extended it, rotate the assembly until the “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). • Install the O-ring over the tensioner body, keeping it outboard of the ridge as shown. • Slide the 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). • Install the cover and tighten. The copper washer should be tight. • Insert the spring through the cover port. As it is slowly inserted, you may hear clicks as it pushes the plunger inward while ratcheting. • Install and tighten the plug against the spring. Note: some 250F engines have a one piece cap. Slide the spring into the tensioner far enough to hold it, then capture it with the cap and tighten. • Start the engine and carefully check for oil leaks. Adjustment will occur internally as it is needed. No further maintenance of the tensioner is required