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Motorized bike, anyone have one?
Willy wrote:

Quote:You can utilize compression braking with 4 strokes, since lubrication is separate from the fuel and I seem to remember something about them having a lower rpm torque band. Also, they're not as sensitive to exhaust system configuration since the exhaust gases are actually pumped out of the cylinder. ..Willy.

That's quite right.  I think the reason for the 2cycle being so popular in the past on small bikes was the size could be small and the power be large. 

Those 2 strokes are most vulnerable to air leaks which may cause a run away of rpm's.   '

30 mph is about as fast as anyone would really want to go on one of these motorized bikes.  Many states limit it to 20 mph.

There are a bunch of 4 stroke motor kits out there but most are more expensive than the 2 strokes by at least $100 dollars.  Which puts it back to the question,  could you find a good used Moped for the same money.

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(12-13-2016, 06:29 AM)eDJ_ Wrote: I was just thinking about this the other day.  You know how we have "Hybrid Cars" ?   Would it be possible to have a Hybrid bicycle ?  

I'm imagining a friction drive front mounted engine that contains an electric motor in the wheel.  Thus the front tire would be the powered wheel.

The rear wheel would have a sheave nearly as large in diameter than the wheel itself.  This would drive an alternator mounted over the rear wheel.  The alternator would be set up at 115 VAC to charge a battery pack
that contains it's own charger. 

Youtube showing an alternator from a Chrysler 5th Ave set up to deliver 115 vac.

The idea is that if you ride under gasoline power the alternator will power the battery charger to charge the battery that operates the electric motor in the front wheel.   When the battery becomes discharged then the
gasoline friction drive motor would be started to continue and recharge the battery in the same time. 

I know it will take some energy to turn the alternator when it's field is energized. So it's going to take a large sheave to turn the alternator.  This may require a poly 4V belt

Where the field energize power for the alternator is going to come from ?  Perhaps a small motorcycle battery
would be capable of it.   The battery for the bicycle motor wouldn't be suitable  I don't believe.

And...I don't even know if this would work.   But it's just a concept for now.  The mechanics wouldn't be that complicated. 

For the sheave a 26" rim mated to a 27" rim would only require a few backward "Z" tabs to be welded to the two rims.   Like so:

[Image: Picture155.jpg]

This is an image of a 36 Vdc front drive wheel:

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So your gasoline motor would mount directly over the top and drive against it's rubber tire (friction drive).

This while the rear wheel would turn an alternator mounted on a carry rack above it.

If it were to require a small motorcycle battery to field energize the alternator for it to produce electric,
then the battery could be recharged when necessary.  (again,  I don't have any idea of how long the field energize signal would have to last.  OR, if the same alternator could be configured to recharge that motorcycle battery at the same time it charges the electric wheel motor.  That would be ideal if it could be done.)

So..........would any of our electric Guru's here know how to put something like this together ?

Here is an electric motor powering a rear wheel with a motorcycle battery for power.  But this works at total loss.

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I was thinking about building a hybrid motorized bike like what you're describing, but it feels like a lot of effort for little gain. The biggest hurdle is the standard alternator is 12 volts and the motor runs on 36v then you need to boost the voltage.
(12-13-2016, 01:05 PM)Willy Wrote: One thing that kinda sux about friction drive is that it wears the hell outta your tire, especially when wet and/or going mud n dirt. I rather l8ke the belt driven units, KISS, and would consider a FWD setup. ..Willy.
At this point I just want something that works and can be brought onto the bus and light rail to augment the range, and I found the electric bike I built with the heavy SLAs need extra attention to walk it (bike will fall over if standing more than 5 degrees off it's center of gravity). Also on the inagurial trip it was a stregnth test to put the bicycle on the exteroir front rack on the front of VTAs bus. I don't care if friction drive is half as efficient compared to chain drive or if I need to replace the rear tire with a solid rubber tire, I just want something that needs minimal maintence and works out. Even if the friction drive is 10 MPG it's still way cheaper than a car mile-for-mile and the friction drive bike is the only motorized mobility I can afford currently.
(12-13-2016, 02:09 PM)eDJ_ Wrote: ...

Willy,  totally agree friction drives are the bottom end of motorized bikes.  No good in the wet and they eat tires like the engine eats gas.  
I can see this, so i'll add "possible tire wear" and "Can be no good in wet weather, due to loss of friction due to wet tire"
Again, even if the friction drive engine eats gas it's still far cheaper motorized mobility than a car.
Quote:One of the set ups I like best uses a Harbor Freight gas motor with an adapter to mount it to the frame.  The
transmission (which I think is grossly over priced)  is a Q-Matic centrifugal clutch drive that connects a chain to a large rear wheel sprocket. (added to the left side so the pedals sprocket is on the right.  Thus motor power on the left and human power on the right.

But, costly as this is,  it will outlast several of those little Chinese bicycle motors. 
I've seen this kind of chain drive motorized bicycle, and I am sure it is long lasting and reliable with quality fabrication and parts. But as you say,
Quote:You "can" get a lot of money in one of these and could have a used motor bike for as much and with it have something LEO's won't be hassling you about. I've come to think that the low end $150 Chinese kits and a yard sale bike for $20 bucks or less may be the best solution for a cheap motor bike. (that you could ride in the boondocks with no problem) But I like the one in the video if I could find a used one someone had tired of and I could buy it right. The motor is a more durable 4 cycle made of better materials, the Q-Matic similar.

As for buying a springer front fork and loads of other "one piece at a time" custom stuff to build with...that's where the money adds up. ...
Agreed, if your partslist for your DIY motorized bike has it's cost add up to exceed $400-600 (depending on what one is looking to build), start researching low-end ready made motorized bikes on Amazon, Ebay, and other websites that sell low-end ready made motrized bikes.

If you desire something that isn't commercially available or you can't swallow the initial price, the "one piece at a time" method is like a layaway or payment plan.

The 2-stroke electric bike part didn't pan out in the real world like it did on paper but the trike part will be a great outcome for this project. As of now I have sunk over $550 into the 2-stroke electric bike and now plan to convert it to a reverse cargo trike by removing the front wheel, u-bolting to the front forks, and then relocating the batteries, chargers and 2-stroke generator onto the bottom of the trailer cart, in a way where I can haul things above it. This was part of the design from the beginning, I wanted a 2-stroke electric bike/trike that I can ride year round in San Jose and legally in BRC; convertable from bike to trike in 30 minutes or less.

In the end I will have a DIY 2-stroke heavy duty electric cargo trike that I can do errands within a 5 mile radius of home, capable of moving me and a load of purchases without getting too much negative attention. It will be reversable back to an electric bike if I decide to do electric using ultra luxe lithium-ion batteries (ulta luxe for me as battery packs start at $350, and I have about $35 to my name right now). The 2-stroke electric trike will have a estimated money cost of under $700, and have stregnth and carrying capacity of ready made cargo trikes costing $2000+. Time costs so far I estimate to be 100-200 hours actively thinking, engineering, researching, comparision shopping, acquiring parts and putting them together. Skill cost is intermediate, as you're doing things to things they weren't really designed for. I plan to post a how-to and build log of the whole 2-stroke electric bike development.

Quote:For the sheave a 26" rim mated to a 27" rim would only require a few backward "Z" tabs to be welded to the two rims. Like so:

[Image: Picture155.jpg]

This is what I was thinking as a compromise for the stated cons of friction drive, belt drive direct to wheel motorized bike.

Regardless, I can't reccommend electric bikes unless you're a commuter who commutes to the same place everyday within the electric bikes battery range, and you can charge the bike at work if work is at the edge of the battery range. I have 4+ years of alternate motorized personal mobility experiecnce and seen everything from senseless boutique bikes to hillbilly machines. For those on a shoestring budget and don't have credit to finance a $1000 initial purchase, and want the freedom to roam without range limits: chain, belt or friction driven gasoline-engined bikes are the way to go.
Working to earn my CDL so I can get ahead & LIVE LIFE!

Time saved is Time Banked* & value added.  *in quality of life context.

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