On Wed, 21 Oct 2015 14:01:25 -0700, etpm wrote:

Because of the size and the way my bicycle frame is shaped it may be
more convenient, strictly from a mechanical point of view, to mount a 2
stroke bicycle engine upside down. Maybe upside down and backward. If I
did this the carb would need to be inverted because it is a float bowl
type carb. I suppose I could use a pumper type carb instead but I don't
know if I have one that is suitable as far as fuel and air flow are
concerned. Besides, small engine pumper carbs tend to be kind of on/off
devices in that they idle OK and and run wide open well but don't do so
well in the mid range throttle settings. I suppose I could buy one but
I'm cheap. So, if there is room to invert the carb what else do I need
to worry about? Will the crankcase tend to get too hot since it will now
be above the cylinder? And lets say that the engine is not only inverted
but also turned around. Now the engine will be rotating the wrong way to
drive the bike forward. Since the engine is a two stroke it seems to me
that I will only need to change the ignition timing. I think this can be
done simply by broaching a new keyway in the spinning magnet flywheel.
The ignition is a fully electronic CDI type with no points. I assume the
ignition works by sensing the voltage rise in the magneto primary
winding as there is no other provision for detecting the position of the
flywheel magnet. Have I missed anything?
Thanks,
Eric

Worry about plug fouling. I don't know if it'll happen or not, but oil
drains down, and oil fouls plugs.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com