This shows the conversion between standard KDX 200 port timing and the Vespa KDX port timing. ## The Variables1997 KDX 200 Specs (Note: This was information given to me and I am not sure how accurate it is)
KDX 200 Stroke = 58mm
KDX 200 Conrod Length = 109mm
## The CalculationsTo calculate the port timing, we can treat the problem as a triangle and use a calculator such as Irregular Triangle Calculator Here is what the diagram below represents:
a = conrod length
## Port Distance in Relation to Crank CentreTo do the calculations we first need to work out the unknown for the KDX 200, which is "c" the distance from the port to the crank centre. Exhaust Open ATDC: 86 deg
A = 86 deg
Transfer Open ATDC: 117 deg
Transfer Close ABDC: 62 deg A = 118 deg (i.e. 180 deg - 62 deg)
Then for the Vespa KDX we can adjust the parameters and calculate stuff... |