could someone give me details on changing oil on a four stroke venture.

ya sure, it is pretty easy

1- take the 7 phillips screws out on the right side panel
maybe use an impact screwdriver or a very new screwdriver
the bigger size phillips (screwdriver) also....they strip easy

2- 5mm allen to remove the 5 screws on the bottom panel (belly pan)

3- drain the oil from the tank( it is close to 3 liters)
a 12 mm socket i think ( i used a crescent )

4- undo the filter (bellypan)
i use a seat belt strap wrapped around a socket extension
channel locks work also

5- take out the drain plug beside the filter, (also 5mm)
it is on the clutch side, it has a copper washer on it
you will only get a tablespoon or so of oil from it

6- put a new filter back in..and the drain plugs

7- fill the tank with 2 1/2 liters of oil

8- start engine... look through the inspection hole ( black plug, by the sparkplugs)
see if there is oil in there splashing , it is only a little oil

9- put the outher 1/2 liter in the oil tank
check the level, it should be closer to the low mark (without screwing in the plug)

10- check it filter is leaking...put plate back on, and side panel

i think that is it

right on. thanks.