Hi Larry
Highjack away
My guess it has something to do with the door opening time of the closed tail and wether they can open when we're laying on our sides.
An open tail bike can throw its chutes laying on its side, a closed tail may have its doors held shut by the salt if its assumed its natural position (on its side).
I messed with several mercury switches and also made some, I would advise not using them.
A bit of a shake triggers most of the bought ones because the tubes are short.
I made a nice v tube one and a vibration broke up the mercury into small balls and it wouldn't reliably trigger, I would get well past the trigger angle about 2-3 times out of 20, nowhere near good enough to use on anything let alone for a safety item.
Looked at pendulums, rolling balls etc and couldn't find anything that I was confident wouldn't either false trigger or not trigger when it goes bad.
I ended up buying one (and a spare) of these;
http://hmbe.com.au/products/2-axis-tilt-switchAt Aus Speedweek I saw a fair few people having difficulty with licencing runs going over or under by a small amount.
I'm not running gauges just a few idiot lights as I don't want to distract myself.
Hummingbird are custom programming a GPS based speed alert for me.
I will be able to set the speed I want and the screen will change colour at that speed and then flash if I got 10mph above that speed, e.g. if I'm doing my 150mph licencing run I will set it at 150, the screen changes from blue to red at 150, if I go over 160 the screen flashes blue/red.
I will put it with the idiot lights just below screen level so I can see it in my peripheral Visio without looking.
The unit will also store max speed.
http://hmbe.com.au/products/gps-speed-alertIf anyone is interested just tell them you want one programmed the same as Jon's Streamliner Bike.
I'm not sponsored by them, I've paid for mine, just thought someone may be interested.
jon