View Single Post
Old 12-04-2008, 11:12 AM
eDJ's Avatar
eDJ eDJ is offline
Motorized Bicycle Elite Member
Join Date: Jul 2008
Location: Wayne National Forest
Posts: 531
Default Re: has anyone seen this?

FinFan wrote:

How would you idle an engine like that?
Recently Deacon experimented with running a string trimmer motor on one of his builds in this way. Probably four months ago now. But when he came to a stop the engine would die and to start out he would pedal until the engine started and then throttle it. It was a friction drive set up and what I'm talking about would have similar characteristics to a friction drive. (but in what I'm talking about the crank would be bolted to the bike and the motor/wheel recropricate around the crank and piston array. I'm just guessing that at low speeds the engine would be set to lose it's ignition by design. The chain drive from the pedals would work similar to the free wheel on a 10 speed so that when pedaled up to a certain speed the ignition would engage and propulsion would ensue once again and the rider not have to pedal. In my scheme the carb could be throttled but if that wouldn't work then there would have to be a system there the ignition is set to progressively engage one cylinder, then two, and finally three in order to create a progressive power
curve for the bike on acceleration and similarly on deceleration.

As to the Dwell Extender, I was just a kid when Grand Dad purchased this little $9 dollar kit from Lawfayette or Onterio electronics to install on Grandmothers little 64 Opel Kadet station wagon with a 948 cc 4 cyl engine.
It looked like the body of a C cell flashlight without the flared end for the reflector and light bulb. The tube was an annodized aluminum body with small extruded ribs which was provided with a couple plastic end caps with mounting feet. The small circut card inside had Grand Dad soldering an SCR diode and a bunch of other components to it. Very simple affair. He did work for ever playing with point settings and ignition timing and each time throwing me in the thing and with him and driving it around. He kept a small note book
recording the settings and notes on what he thought he was getting from it.
I remember he had a magazine like Mechanics Illustrated with an article abot the dwell extender where they tested theirs on the 4 cyl and a big 8 cyl and
offered their views and feedback.

xPosTech, I am so glad you explained all that and if it were up to me I'd edit some of it and make a Classic Sticky with it.....the explanation of dwell and pont gap influance on timing etc. Good basic nuts and bolts info.

I was just a kid and remember grandmother grumbling how she wished he'd leave her little car alone whatever he was doing to it. She couldn't see any difference in the way it ran excepting that it had a little better "take off" as she would call it. Of course I couldn't say anything about what I heard either of them saying. I used to laugh at how small the motor in that Opel was though as it was about the size of grannies sewing machine. But the little Dewll Extender stayed with it till it's dying days when the transmission finally
went out. It had a little top shifter 4 speed.

That was my only experience with a Dwell Extender. I was wondering if there was any applicability to the concept today with a Gnome cycle motor.

As far as the lacing of the wheel spokes I guess that should wait till the motor is actually thought out. In one old photo I once saw there was a dish used in place of spokes where the motor was nested into the dish thus giving a solid
wheel form. If that creates the aerodynamics of a crude airfoil, it may lead to
a more accelerated over the motor at speed. Perhaps that's what they were thinking back then. What's running thru my mind is to vent the exhaust thru holes in the dish and configure the timing of exhaust release so it would happen at the 4 o'clock and 8 o'clock position when looking at the dish side of the wheel. (thus keeping the exhaust low to the road or aft of the bike if the motor wheel is used in the rear. So the exhaust would occur between the 4 o'clock and 6 o'clock arc of the circle and the 8 and 10 o'clock position. The rear fender covering the tire may be cut at the 10 o'clock position to keep exhaust overspray off the bike.

I know it all kinda seems hair-brained but if such a system were offered commerically, the frame dropouts would have to be replaced with the specialized ones I described. The electrical "kill swithch" would come out of one side of the axle where the mag is and the carb intake thru the other side of the rear axle. I'm wondering about a reed valve with the carb too.

But this kind of "dreaming" or "Imagineering" is what we Industrial Design people do for Sales who in turn present it to the Design Engineers. Otherwise we take what Sales gives us and style it up sexy so people will go "ga-ga" over it and buy it. (a problem such as we've seen in this thread is that some
producers come up with half baked products and want to go running off to design houses with them to get them sexed up for investors or market.... before they have a proven viable/dependable product to offer)

As far as a rear brake a disc may be most practicle as it would be out of the exhaust spray fog.

I think something like this could work and there may be a market for it with some. It would rely on high quality and dependability with low maintenance.
And should probably be buit in it would be sure to have the craftmanship to assure that.

What would such a thing sound like.......I would rather imagine it sounding like a pressure cooker and 3 cyl motors seem to be inherently noisy.

Driving it.......probably similar to any other bike except using the kill switch of some form to control the speed or have a governor that could be set for a top speed to comply with limits. This if the carb has to run wide open with a diaphram chamber atop the carb in order to allow the slide to throttle itself.

But these are just my musings.

Last edited by eDJ; 12-04-2008 at 11:14 AM.
Reply With Quote