So WHY do we need to line up the C and the pointer to adjust the camchain?

[Courtney]

Just thinking about this? It's an endless chain, so why do we need to line up the C? The tension must be the same all the way around the chain, despite piston/crank/cam placement???

[motoman]

Just thinking about this? It's an endless chain, so why do we need to line up the C? The tension must be the same all the way around the chain, despite piston/crank/cam placement???

It may be because the cam lobe positions create the least amount of load trying to 'fall' off lobes under valve spring tension, which stands the possibility of 'taking away' some of that slack which ALL should be on front-side of chain. The ONLY way chain tension is held constant ALL the time is by replacing the waltdisneydesignedmickeymouse stock tensioner with one of the many auto-adjuster options. Cams stay in time ALL the time, which results in an even smoother running motor thru ALL rpm ranges.

[GLoweVA]

It may be because the cam lobe positions create the least amount of load trying to 'fall' off lobes under valve spring tension, which stands the possibility of 'taking away' some of that slack which ALL should be on front-side of chain.

Moto hit it on the head. I've watched my chain while hand turning the crank to get the cam sproket bolts in and he's right, there are certain times when the cam lobs want to rotate due to the spring pressure, at the C mark, the cams are lined up perfectly (as far as chain tension) and all the extra chain slack is in the front of the engine where the tensioner is.

[Bonz]

Good explanation Motoman.