Craven wrote:Fascinating how when the workshop manual illustrates where and by how much the chain total movement is assess, other chose to disagree.
I have observed the difference in the drawing versus the written text and also tested with various amounts of free play between the cams ensuring the other legs of the chain run are tight.
My observation was that around 3/8 inch total movement of the chain or around the width of the chain itself was good and produced low noise and never any tooth jumping issues. Going much tighter than this and certainly going to the drawing 1/8 inch of total chain movement caused the chain to whine. Going above 1/2 inch total movement caused the chain to start to rattle. I did not explore how loose you can run a chain before it comes off on a live twincam for obvious reasons
General chain tightening recommendations talk about 1/4 inch minimum or 2% of sprocket centres if larger of chain droop on a horizontal slack run between the pulleys away from the straight line between the sprockets. This equates to 4% or 1/2 inch of total movement above and below the straight line and this is consistent with my observations and the Lotus text recommendations.
All told I would trust the text not the drawing interpretation of the text
cheers
Rohan