Schwinn Point Beach FD Remake

cannonball2 · #1 12-15-2011, 12:21 PM

I posted the build of this bike I built for my wife a while back. She bailed on MB riding so figured I would do a different build with it, and rearrange what was there. Was impressed with Wayne Zs inframe build so it bears a great deal of resemblance to it. Mine is a single speed however and built in a vintage style. The drive is cantilevered off the engine mount so as not to burden the aluminum frame unduly. The shifter really is an engagement/disengagement lever for the roller. I can quickly totally disengage the roller for pedaling, or add or subtract down force as conditions demand. The drive is through a centrifugal clutch, so the bike will pull from stop with out pedaling. A spring loaded idler keeps belt tension constant as the roller is moved through its travel. The driven pulley is adjustable to vary the ratio if needed. Thats an HF 79cc mounted. I have a 99cc Preadator going in after the tear down for paint. Except for hardware and a few details its about ready to run.

cannonball2 · #2 12-15-2011, 12:22 PM

Drive pic.

**2door** · #3 12-16-2011, 06:36 PM

Very nice build.
Congratulations on your success. I'm curious about the fuel tank. What is it from? How does the bike run? It certainly looks good. Thanks for sharing with us. I'm sorry your wife gave up on motorbiking. I built one for my wife that she never rode. I recently sold it to a neighbor to help finance my latest build.
Tom

cannonball2 · #4 12-16-2011, 07:44 PM

Thanks for the reply and the positive comments. The tank is a Whizzer repro from ebay. The bike has not been run in its current build, but should be a good runner as it was run a good bit by me in its old configuation, with most of the same components. The roller size with the current gearing should yeild a top speed in the mid thirties. I like to cruise in the upper 20s, so it should be a comfortable ride rpm wise. I have pedaled it around a bit and am impressed with how well the Thick Bricks ride. It is very close to a maiden, I just need some specific hardware and a fuel tank fitting, and its time for a ride.

MEASURE TWICE · #5 12-16-2011, 11:54 PM

CB2... Very nice indeed!

With the gen rub on the rear tire side for front head lamp, does it have a battery for when at a stop and engine idle?

I would think it is already been mfr'ed or atleast someone has done it here. As an electronic tech I off hand right away would think a rechargable battery and and circuit regulated meant to charge the battery from the gen. The light tapping energy from the battery while at stop.

The other way hook another gen meant for a range of engine speed right at the crankshaft, but please keep a fake tire rub gen for looks!

The retro stuff but shining is just as good as the unpainted rusty!

Measure Twice

cannonball2 · #6 12-17-2011, 08:03 AM

Thanks MT! I was thinking of adding a small gel cell 1.5ah battery I found at ACE. It is so small it can be hidden. Was wondering if a diode in the circut from gen to the battery would work so the battery would feed the light when the gen stopped. I had a bike with the gen running off the flywheel but the lights were very dim at idle because of the low idle of a 4 stroke, still was better than total darkness. I really wanted to make this bike into a well patinaed "survivor" type bike but just cant bring myself to rough up/rust up something. Too many years restoring stuff I guess. I would surely love to have a bike done up like the Hogthorne, but I would have to buy it that way. So this one will get fresh paint and a bunch of period vintage decals.

MEASURE TWICE · #7 12-17-2011, 08:57 PM

CB, I have just looked over your reply. Please note right now after me being a light weight and having just found I can get Shlitz Beer with the retro Classic 1960's Formula, I can just reply in overview.

The diode would be in series between the generator and the battery so that when you’re at a stop and there is no current from the generator flowing, the battery does not charge the generator. Funny I said that, but I suspect you know that a generator would not like to get a charge.

A few more things are that the diode will probably have a forward voltage that will drop about 0.6 volts so that the generator has to put out enough to overcome both the 0.6 volts plus about 1 volt above the battery to allow for charging. If it were a 6 volt battery and 6 volt generator that would not do, it would have to be 6 + 0.6 + 1 = 7.6 volts output from the generator or higher.

Thinking of what could work is I’m remembering that they were 6 volt generators, so that two just using three of the high amperage hour AA rechargeable nickel metal hydride cells (like the Enercell 2500 mA) in series for nominal 1.2 times 3 = 3.6 volts could work in a scenario.

The diode also must have enough current capability for the job or it will burn out. This is where a current limiting resistor can be added also in series with diode so that just allows for a trickle charge of the battery and the diode is saved as well from over current as it does get the same current through it.

I’d have to look at the specs of the parts first before getting any of the parts to know it would all work out. I just thought that Nuts & Volts Magazine I have subscribed to or ARRL probably have a circuit worked out. I’ll check on that. But since I was going here is the rest in a pinch.

6 volts minus at most 1.25 top off volts times 3 = [6-(1.25*3)] = 6-3.75 = 2.25 volts 2.25 volts > 1.6 volts by 0.65 volts to spare.

With particulars not yet figured but can be done later for the components for the trickle charge circuit to the battery, using a handful of the real bright white leds would mean most likely the generator charging the battery would be enough never to have to take the batteries out and charge them with a home charger.

Though the huge bulbs if you could get them in a lower voltage so that they could work with the 6 volt tire rub gen in the above scenario would be fun to see operating full retro. Those dotted bulb surfaces for the light diffraction are such a charm, unlike the leds.

There is actually a way to overcome the problem if you really want the retro bulbs and the 6 volt gen and 6 volt or whatever came with the gen light set uses for bulb voltage that are too high to work.

This is a very small DC to DC converter that is about 15 or 20 dollars and is adjustable. If I remember right it took as small as like 3 volts and had a step up to as much as 20 volts with a little loss in current, but still efficient. It was rated at about 1 amp. No one could be the wiser why you had light output while idling!

Measure Twice
PS …. I’ll look to see what is already been done and get back to you

cannonball2 · #8 12-17-2011, 09:43 PM

Thanks for the input MT. The generator is a 12v unit, as is the little battery I have spotted. I am no expert on electrical theory, but was trying to rig something like the alternator warning light in a car. I believe the light is put out when the alt. voltage exceeds the battery voltage. So is this possible? The diode would only allow the voltage out of the gen. When/if the gen voltage exceeded the battery it would power the lights, otherwise the flow is from the battery? The diode keeps the battery from flowing back into the gen. Maybe it needs two diodes, one keeping the flow from the gen out of the battery, and the other keeping the battery out of the gen. Dont really want to charge the battery, just use it as supplement. In theory a charged battery would last a long time if this would work.

MEASURE TWICE · #9 12-17-2011, 11:14 PM

A slow charge when at speed made possible by limiting the current with a resistor is what is called a trickle charger. Having a greater voltage by a small amount is at least necessary to have the battery get charged. If the voltage is a lot more to a point, it really still does not matter as long as the current is limited by this part called a resistor. The ohm value of the resistor is chosen to limit the amount of current that flows.

Now what you said about having them separate altogether and no charging from the generator to the battery, that is a different story. I think it is a good way also.

I did a similar thing a while back with a getto blaster so that when in my car without a FM radio or cassette player installed in my car, I could use the car battery to run my getto blaster and turn off the connection to the internal D cells so as to save money on batteries.

I used a relay and when I plugged a cable to the cig lighter and to my getto blaster I had the D cells inside the getto blaster disconnected and the car battery supplying the getto blaster instead.

This was done by my connecting and disconnecting, not what you want done manually.

It can be automated and a special diode called a zener diode and a resistor. The zener diode is specifically different than a regular diode allows you to pick a voltage that you want to drop from a circuit. So where it all comes together is choosing a relay that will activate its coils and trip the relay to switch when the generator output is enough to give a respectable amount of current to run the head light and save the battery pack, like at 9 volts. There is just one thing additional that if the voltage on the generator does not go up to near the 12 volts as you said it does at slow speeds, but rather ramps up, you could possibly be going at a speed that the relay starts to try to close, but instead chatters.

Additional circuitry to eliminate that with an op amps configured as comparator with a degree of hysteresis (no middle) could be added. The op amp could use power from the battery to operate and the amount it uses is next to nothing.

I’ll look to be see what has been done on that kinda circuit. The library and many online educational places have a lot for free on this. One that always comes to mind is HowStuffWorks.com Take a look there, lots of stuff!

Measure Twice

cannonball2 · #10 12-18-2011, 06:51 AM

Thanks MT. I remember my old Triumph had a Zener in a heat sink under the head light. Would one of those work? So what happens if the gen can feed the battery and lights at the same time. If a diode was added so the battery voltage cant enter the gen and an on/off switch cut the battery to the lighting circut. If you cut the lights on the battery feeds them, but not the gen. If the gen voltage exceeds the battery voltage wont it begin to flow through the diode? This should happen when the battery begins to discharge from running the lights, no? Forgive my ignorance on the subject, I am very familar with wiring , but not theory.