Well I got the motor in the drill case and the whole mess re-installed. Switched back to driving into the slack side of the chain. I think it looks cleaner. The frame clamps and mount work great.
I've taken it for a ~10 mile shake down run. The 13T freewheel I've got is driving my nuts with its loud ass clicking. Anyone know how to shut it up? This new system pulls better than my last motor, but it's spinning a bit too slow. Maximum assist is at a cadence of 50-60rpm. When it's on this system is much quieter than the last motor. Gearbox still sounds like a coffee grinder, and it generates a subtle high pitch hissing noise. I can hardly hear the motor at all though. Oh yea, the new battery drains the battery quicker too.
I'll be making a couple of 1-2 cell booster batteries to hook inline with my current pack. I want to confirm the best battery voltage BEFORE I buy a new battery pack. I'll also be upgrading the 5ft 12-14awg battery wire to 10awg to reduce system resistance.
@Paultrafalgar: The gears in the drill are spiral bevel gears, and they are at least as efficient as straight tooth bevel gears. Specifically since the axis of the input shaft and output shafts intersect, the gears have an approximately rolling contact and waste very little energy.
@TylerDurden: ... Last time I checked dental drills spun a itty bitty bit faster than 219rpm. Though I have to say the blaze orange case of the drill adds a whole new level of ghetto to this bike
First picture is the whole system ready to install in the bike.
Second pic is a closeup of the system installed on the bike.
Edit: the converted drill weighs 3lb 10oz (1643grams) I estimate that the whole system weighs about 6lb.