Hey Paulweldit . . .

This evening I built a 360 cell spread sheet to model the 'advertised' duration versus the .050 lift spec for the DP #2 regrind. The cells in the spread sheet go from 1 to 360 oriented to TDC.

The intake has an advertised duration of 250.

Based on the valve events documented in the book the model indicates that the valve would open at 345 degrees ATDC (on the exhaust stroke) and stay open until 235 degrees ATDC. Assuming a constant lobe lift of .002 per degree of rotation - maximum lift should occur at 110 degrees ATDC. With 1.5:1 rocker ratio the intake valve is only beyond .050 lift from 1 degree ATDC until 219 degrees ATDC - or 218 degrees.

For the exhaust the advertised duration is 280.

The valve events would occur at 113 degrees ATDC and 31 degrees ATDC. Assuming a constant lobe lift of .0018 per degree of rotation - maximum lift should occur at 252 degrees ATDC. Again with a 1.5:1 rocker ratio the model suggests that the exhaust valve is only beyond .050 lift from 130 degress ATDC until 14 degrees ATDC - or 244 degrees.

These are much more reasonable numbers and lead me to think that this may well be the right cam for my ride.

regards,
stock49

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