I made my initial attempt to find the clearance and swept volumes of the cylinder today. The first obstacle was getting the spark plug opening to the highest vertical position and level so that any air in the cylinder will come out of the hole rather than staying trapped and displacing some of the oil and throwing off the measurements. To do this I positioned the kart on its side after removing a few components to gain better access.
The next problem was turning the engine over by hand.Initially I had planned to use the crank shaft end bolt, however this would mean draining the engine oil to gain access to it which I wanted to avoid. Next I tried rotating the sprocket on the output shaft of the engine, but the fitment of a centrifugal clutch mean that I would need about 1000 rpm to get the engine to turn.
Next I tried the kick starter. Since this is a go kart and not a scooter, it doesn't actually have a kick start lever. After improvising a coupling device in lieu of a splined lever, I found it lacked the slow controlled movement I required to accurately measure the volume of oil in the cylinder. The spring loaded motion produced by the kick start mechanism causes the crankshaft to go through at least 2 revolutions in rapid succession, forcing the oil in the cylinder out of the spark plug opening very aggressively.
My next attempt used the starter motor at low voltage to slowly turn the engine over. This was also ineffective due to a lack of fine movement control.
As the end of the day approached, two challenges became apparent. That I must remove the crank cover, and that the timing chain would likely need to be removed as well in order to keep the valves closed while pumping the oil in and out of the cylinder. These two issues will be tackled next week.
