A couple of years back- some company in Australia came up with a disengaging clutch on the motor side sprocket- the trouble was that you had to get off and disengage it- I had written a thread here long ago that we needed a disengaging freewhell on the motor sprocket- but you really need it while riding- not getting off to switch it over- like the very first derailleurs long ago!
http://motorbicycling.com/showthread.php?t=8687
Yes- there is the centrifical clutch and then pull starter- but the pull starter generally requires then that the cranks be set another inch wider, so that's areal negative trade-off to cyclists otherwise.
As my bikes are, and the type of riding I do- I really have dropped the issue in my own mind- with good wheels and lightweight components , and the newer chain- they pedal quite nicely for the short distances I need- if I break down and had to pedal- I'm good for many miles- but I wouldn't want to pedal it like that all the time! Around the store parking lots, or crowded pedestrian areas I'm all set- just peddalled through the park beside ther St, John's river here in Jacksonville today- no problem at all and very minimal resistance or noise from the extra chain and sprocket and motor bearing.
http://motorbicycling.com/showthread.php?t=24770
I'm totally motoring now in mostly short bursts in the urban area- I get up to speed and go as far as I need and if there's a stop up ahead- I hit the kill switch a block or more (largely depending on the wind- everything's flat here otherwise} and I coast up to it- arriving at cycling pace- enjoying the quiet roll every bit of the way-
and I'm not grabbing the brakes super hard then and wearing out the pads that much sooner- it's truly combining cycling and motoring- and my fuel just lasts and lasts-
If someone got 100 or 150 a gallon, motoring 26" wheels with beach tires around with the motor on most of the time- I may even be DOUBLING that mileage- and actually pedalling very little to do it- I'm just coasting a lot, on a bike that coasts almost like a roadbike- but a roadbike that's starting at 30 mph!
One thing about the 415 Trike chain- it's STILL the same dimension basically- the pitch and the width- if you think a 415 is sloppy now you may not like it any better. (I've tried the 410 narrower 1/8" chain, and narrow motor drive sprocket, and I thought it would be too finicky to get and stay alligned- I don't want to mess with the chain all the time)
But the TRIKE chain is just as light or lighter than the 410 and still allows for play. The plates are smaller verticly- so if you're a hard motoring guy with a heavy body or bike and you've had any trouble breaking chains from anything but misallignment the Trike chain may not be for you.
http://motorbicycling.com/showthread.php?t=41032
But as an ex-road cyclist for 14 years, who wants to maximize both pedal and roll- I've used two of them now for almost two years withourt a problem- and they really roll smoother.
Has anyone here mentioned greasing the sprockets inside the cover?- that helps roll too and QUIET.