DR650se - Finding Top Dead Centre (TDC) on Compression Stroke
  • For many operations such as measuring Valve Clearances, removing Cam Chain Tensioner etc, it is necessary to get the the engine to TDC on the compression stroke. There are two TDCs, one is the compression stroke where the valves are closed and the other is the exhaust stroke where the valves are open.  The best method of finding the correct stroke is to remove a valve inspection cover and check for play (gap) in the tappets once the timing mark has been reached in the inspection cover. The full procedure is outlined below and is provided as an alternative to a straw in the plug hole trick.
  • For this operation it will be necessary to remove the sidecovers, seat and fuel tank to allow access to valve covers and spark plugs

  1. Remove valve inspection cover (s)
  2. Remove a spark plug (makes it easier to turn the engine over by hand)
  3. Remove magneto cover plug - careful not to strip the hex head (10mm Allen key)
  4. Remove timing inspection plug to inspect timing mark (8mm Allen Key)
  • With the bike in neutral, get a 17mm socket onto the nut inside the magneto cover cap and turn the crankshaft over slowly counterclockwise until the horizontal line below the 'T' on the magneto rotor is central in the timing inspection hole.
  • Test tappets and if no gap or play in them, rotate crankshaft another full rotation until the 'T line appears again. Test for tappet gap now and if there is play, you are on TDC compression stroke.
  • **Take special care to not turn engine over from this point