[johngustafson]

Hi, because of renewed interest, I restarting a thread on the building of my Hybrid gas/electric motorcycle. First, I would recommend you see the website:

Classic Hybrids: The Hybrid Motorcycle Project | Unique Custom Cyles & Restorations....

This will provide a lot of info.

I guess the first issue I'll tackle is why I built it:

When I decided to build a bike, (February 2006), I decided that i wanted to see if I could make a bike with large displacement performance, and small displacement economy. Prior to this build, I had zero experience in building a complete bike. I had no prior experience in electric vehicles (slot cars not included) and I had no idea what the engine, motor, controller, or batteries needed to be. I did however have a picture in my head as to what I envisioned it to be.

My first stop was to see how others on the internet were building electric bikes and go from there. Most of what I saw was discouraging. Huge low power batteries with limited range, hanging out of an overburdened frame. Not something I wanted to see in my bike. I then started researching businesses on the web that sold the various components for an electric bike. There is a lot out there, but most are not suited for the Hybrid Application. I will discuss this later.

So, I took a leap of faith and asked a close friend if he had an old bike he'd be willing to donate for this cause. He dropped off a very beat up 1978 Honda CB750K.

Next, I decided to take a leap of faith and decided to just buy a few small components and try them out to see they would work. The one I chose was a 200 cc Hensim Chinese engine. I also purchased a 1200w motor and a matching controller.

With this, I began to attempt the build.

 

[Harvey]

is the motor Atkinson cycle? also I believe that electric motor is a dc brushed motor, how are you going to preform regenerative braking to recharge the batteries?

 

[ILoveThumpers]

Where did he mention brake regen? Hensim motors are 2 and 4 stroke. They are found primarily in dirt bikes and ATV's.

-Deek

 

[johngustafson]

Hi, John here. The engine, which is a 200cc Hensim dirt bike engine, runs a conventional Otto cycle four stroke. I choose it because it was relatively cheap, was known as being fairly reliable, and gets great gas mileage. 8 years and a few thousand very hard miles later and I've yet to break it.
As for the motor, it is an Enertrac 602 Hub Motor laced to a Warp 9 17" x 3.5" alloy rim. It produces 10 kw continuous and 30 kw bursts. It is controlled by a Kelly style 90 volt 200 amp motor controller with regenerative braking and temperature sensing to prevent overheating.
The batteries are LiFePo Nano foam packs with 37 volts per pack. They are arranged 2 in series, 2 in parallel, for a combined 74+ volts and 10000 milliAmps at full charge.
The throttle is all fly-by-wire, with a servo controlled carb, and a custom throttle control for the motor controller.

 

[johngustafson]

Hi, John here,
The motor and controller shown in the pics I posted are from a small company in Tennessee that sells electric scooter parts. As I had no previous experience in building anything electric, the specs meant nothing to me. The motor is 1200 watts, capable of 48 volts max, but 36 volts continuous. The controller is a tiny thing with a Hall Effect throttle. I used four 12 volt advanced glass mat batteries in series (48 volts), and started to build. It was unsuccessful as motive power was concerned, but it taught me a lot.

 

[johngustafson]

Hi, John here again…
After the tiny motor/controller attempt, I moved up to a professional style motor from Advanced DC in New York. This was a 2200 watt series wound motor, so no regenerative braking. These are extremely sturdy little units, very hard to break. It too runs at 36 volt (48 max) and is quite powerful. It is the motor seen in these pics.

While everything fit into the frame, it was a clunky design, so I tore it down and began again.

 

[johngustafson]

Hi, Final Thoughts for the night….
My original idea was to build a gas/electric cafe racer that would be unrecognizable to the average person viewing it. It would appear to be just another nice bike. My final attempt was made possible by stumbling into the site for the Enertrac Hubmotor. This is a high voltage, low current device that has LOTS of power…it is also one of the more expensive units available. Purchase of one comes with the full engineering back-up and support of the company. This I can attest to! As they had never before or since applied this to a hybrid design, they were keen on seeing how it would work. I must say, it works nicely.
I spent most of the time on the third version of this bike in repackaging the components. The hub motor appears to the casual observer as a drum brake…and most assume it is because of its size. They always seem to ignore the rear disc brake…
The controller sits beneath the seat, making it centrally located for running cables to and from it. The batteries are hidden beneath the fuel tank, which was professionally modified, and pressure tested before being put into service. This is what gives the bike the empty frame Cafe Racer appearance. The bike weighs in around 325 pounds, so its not too heavy, and the little engine does a pretty good job of keeping it running at speed.
The electric motor is used mainly for accelerating from a stop and also for hill climbing. It gives an additional 40 hp to the bike, but also a huge boost in torque. The controller is fully programable and can tailor the performance of the bike dramatically.

I hope this has helped to answer a few questions and possibly raise a few more.
I'll answer any question I can.

Thank you, John

 

[Harvey]

Where did he mention brake regen? Hensim motors are 2 and 4 stroke. They are found primarily in dirt bikes and ATV's.

-Deek

He didn't that's why I asked. Typically hybrid vehicles use regen. You can get an additional 10% or more in range with it.

 

[Geeto67]

ok, so now that the thing works...what's the range? what's the top speed? MPG? Acceleration times?

I am not sure this project answers any questions currently being asked by the performance bike world. You lowered the bike which makes it handle worse (and done other things to a cb750 chassis to make it handle like shit) so I know you aren't after faster lap times...but really where is the ground shaking improvement this is supposed to bring? explain it to me.

I get that this tech needs to progress, and sometimes that needs to happen by men in garages building useless machines. But is this a useless machine or not? that is what I am trying to figure out.

 

[Harvey]

what is the amp hour rating on the batteries? if your motor draws 10000 watts divided by 74 volts is 135 amps, you will need alot of batteries to get even a little bit of range.

Example: a 48 volt motor operating at 10000watts wil need 500 amp hours of battery capacity to run for give or take an hour before needing to be recharged, depending on the efficiency of you controller/inverter.

your system will require alot of batteries to even run for 5 mins before having to regen or charge the batteries through the gas engine.

 

[johngustafson]

While the bike has regenerative capabilities, I have not connected it. We are still working on smoothing out the throttle, as it controls the both the engine and motor. i didn't want to add in the variable of regenerative brakes to the equation.

 

[johngustafson]

While the bike has regenerative capabilities, I have not connected it. We are still working on smoothing out the throttle, as it controls the both the engine and motor. i didn't want to add in the variable of regenerative brakes to the equation.

- - - Updated - - -

While the bike has regenerative capabilities, I have not connected it. We are still working on smoothing out the throttle, as it controls the both the engine and motor. i didn't want to add in the variable of regenerative brakes to the equation.

 

[johngustafson]

I apologize, I just wrote a response to your questions and it seems to have disappeared. I'll repost again when I have a chance.

 

[johngustafson]

I'll try to see if this response goes through.
Range: Unsure as I have yet to trust it for a full run tip the tank runs out. The gas engine gets about 70 mpg (which is pretty much stock for this size engine). The hybrid system was designed to help the smaller engine accelerate up to about 50mph at which point it goes into a trickle mode to reduce drag. I do not have the regen connected. The batteries can take the bike about 3 miles on flat ground at 50 mph. I wasn't going for more than this. Again, It was designed for multiple acceleration runs. It can hit 60 in about 7 seconds.

You made a comment that by lowering the bike, the handling was now shit. Your assumption is wrong. The geometry of the suspension is the same, only lower, the only change is the travel. The suspension was set-up to the weight of the bike and myself. If there is a problem, it is that the kick-stand bracket can scrape on left turns. And no, I am not going for lap times at a track. I'm sure a ride on it would prove me right.

Why did I build it then? First, I wanted to see if it could be done. And while I managed to pull it off, I will admit it was incredibly difficult. I'm sure an internet search of actual running hybrid motorcycles will show a lot of conceptual designs, few if any of them are real or running. The real Hybrid bikes that are for sale (Piaggio MP3, and a Hybrid Scooter made in Bangalore, India) which are both scooters. The concept bikes proposed by the big bike companies have yet yo see the light of day. The closest I've seen to a real motorcycle is the Yamaha HV-X, which is within 10% of my original design…(and, btw, is laid out almost EXACTLY like my second generation bike, with the exception of the small fuel tank and the motor controller)
Second, bike tech hasn't really made any great leaps in the last generation, with the exception of the introduction of electric bikes. We are still using the same ICE with just modern electronics, but the machinery hasn't changed much. Someone had to take the risk, why not me. And while I don't want to compare myself with Soichiru Honda, even he had to start somewhere…and his first attempts were not perfect either.

Is it ground shaking? That all depends on your definition. For me, it is a success because I managed to build what I envisioned. I wanted a modern hybrid drive train in a classic bike. I also wanted to pay homage to the classic CB750K that gave its life to become this machine. It is a bike built for me. I use it as a daily rider, on short rides around the city. And the beauty is that nobody knows that its anything but an old bike. It is certainly not useless, and it brings me tons of joy.

I hope this has answered your questions.

 

[Geeto67]

You made a comment that by lowering the bike, the handling was now shit. Your assumption is wrong. The geometry of the suspension is the same, only lower, the only change is the travel. The suspension was set-up to the weight of the bike and myself. If there is a problem, it is that the kick-stand bracket can scrape on left turns. And no, I am not going for lap times at a track. I'm sure a ride on it would prove me right.

its not wrong. While you have slightly decreased the frontal area (and therefore the drag co-efficient), you have also increased the force required to get the bike to change direction. You don't see lowered road racing bikes in racing do you? In fact the only time you see a lowered bike is in straight line racing. You also removed the fender and fork brace and cb750s have a lot of flex in the forks to begin with.

I guess to me seeing if it could be done isnt a goal. Of course it can be done.,goals are usually something like performance aspirations. I agree that strides need to be made in the area, and I commend your why not me attitude, but really I guess from an outside perspective if it doesn't have ripping acceleration or jaw dropping fuel economy and range, it doesn't bring anything to the table. The performance figures you are putting out now (which I assume are just paper figures since you haven't ridden it) can be replicated with an off the shelf royal enfield 500 single. I will await your actual testing and hard data before I pass judgement, I hope it outstrips you expectations and what exists in the marketplace.

 

[Harvey]

How long does it take to recharge the batteries after they have been drained to 10.5 volts after that 5 km stretch? The max you could recharge the batteries safely is like 4 amps correct? This would take hours wouldn't it?

I like this project however I think that you still have a lot of things you could do to make this bike worth the money and effort. 5 kms of range between charges is not going to save you any more money on fuel than making a 250cc bike lighter and more aerodynamic. Unless you were to somehow figure out how to fit a copious amount of batteries onto that bike, it is really not going to get any real attention from enthusiast whether from this forum or any eco enthusiast forum.

Why not use nickel batteries like the Prius? I own a Prius and my batteries recharge very quickly through regen and coasting downhill. I don’t think your battery choice is going to do what you want them to which is recharge quickly after acceleration.

lifepo4 batteries are light weight and small which would be ideal for a fully electric project, but do not recharge quickly and can not be charge with a high amperage charger.

you should also make the bike handle better like Geeto said.

 

[johngustafson]

Your comment about the handling being poor because of the drop in suspension is based on the use of the original components of a CB750. And if these were indeed the components being used, then yes, you would be correct. As with all aspects of the bike, most of the good things are hidden. This includes the drivetrain, suspension, electronics, etc...
Do you not think that if a person has gone thru the trouble of creating all the other custom parts of a bike, they would drop the ball on something as fundamental as the very thing hold the bike up. The rebuild and redesign of the suspension was not a simple "drop" as seems to be the assumption. There was a lot more thought and design put forth than is apparent in what you see in a picture. This includes internal components that are not always seen. As for the removing the fork brace, yes, that would make a large difference, if it was the original components and design. It is not.

You also made a comment about the performance, as in acceleration, or top speed. I suggest you brush up on your knowledge of the characteristics of electric motors. I built this with the idea of increasing efficiency. In my second generation bike with a less efficient motor, controller and battery set-up, I was able to break the 100mpg mark. This design is not only more powerful, but also far more efficient. I think it's safe to say it will better the former numbers. As I stated in an earlier post, I haven't done the test, so I'll withhold any FINAL numbers until I can safely verify the performance/

As for straight line performance. The Enertrac Hubmotor generates in excess of 100 lb-ft of torque. The torque of an electric motor is a function of the current supplied. The speed is a function of the voltage. This is all controlled by the programming of the motor controller. Since I do not wish to have the bike flipping over on my chest during acceleration, the programming has been softened to allow for a gentler start. It is quite capable of large bike performance at the expense of battery life. As for top speed, I am limiting myself as I do not wish to have batteries hanging out all over the bike. The motor is quite able to take in excess of 144 volts, which would give a top speed well over 120mph.

The next thing is the range. I did not build an electric bike, I built a hybrid. As I didn't have a template (no one does), it was a mater of trial and error. I wanted the bike to look nice. So the number of batteries was limited. If I chose, I could slap a pile of batteries into every nook and cranny on the bike and get increased range. I chose not to. I chose LiFePo batteries because they are small and light, and can take a large number of cycles. Also, as for range, even a Prius can only travel a few miles on its batteries alone. But thats not the purpose of the batteries, they are to help the vehicle get moving, to take advantage of the best characteristics of each component. Electric to get started, ICE for high speed.

The batteries take about 2 hours to recharge, and this is fine for my purposes.

What I would do is wait for the Hybrid Bike from Erik Buell Racing to come out (400 hp), and you'll see what a hybrid bike is really about.

 

[Emit R Detsaw]

You've got a relative buttload of space behind the engine and in the "open triangle" to place batteries. Why not?

Hey, good on ya for thinking differently, however...

Geeto is correct. The bike is less compliant over bumps, has more flex, and less ground clearance, but apparently you don't ride it very hard or you don't care. The fork brace was integral with the stock fender, BTW. It may have been a thin piece of stamped steel, but it still did something.

Did you load the fork with cartridge emulators and get Hagons or Works shocks? It appears you did not, at least on the back end. My x-ray specs don't work on photos, so I don't know about the front, but it looks like stock up front and cheap pattern shocks in the real. Good thing you don't need it to handle well for the type of riding you do.

Oh, and aim the headlight correctly. You're either looking for bats in trees or don't ride at night.

 

[roccitycafe]

i guess the target should be using the gas engine for cruising and kicking in the electric for acceleration? that seems to be the best way to go, unfortunately at only 70mpg on the gas side, it's not a really impressive number... I wonder if there's a way to tweak the engine for better mileage, maybe looking at pseudo-atkinson cycle and having the cam built up and reground for a very long intake duration and very late closing, or something else... not really sure, just throwing out ideas. Overall though, my 400f got ridiculously good mileage without electric assist, and was pretty fast when it wanted to be as well, so I think your target needs to be moved further up... but who knows, maybe with a running hybrid bike, you'll slowly develop it bit by bit

 

[johngustafson]

If the empty space behind the engine was full of batteries, it wouldn't look much like a cafe bike. Again, I wasn't going for around the world range, I was trying to make it work. I saw no benefit in buying a buttload of batteries if i couldn't make it work. I feel many of the comments being made are because i'm failing to communicate my vision of what I wanted. It's a concept bike that just happens to work. As for the suspension, they are far from stock, but I'm not a suspension expert. I'm aware of the function of the fender brace. As the front is now 4" shorter than stock, and is preloaded, the flex and and clearance are never a problem. The handling is very good. I've been riding bikes since I was 6, so I feel I've got a few years of experience of what a bike should feel like. I do care how it feels, handles and responds. The rears are shorty shocks rebuilt to the weight of the bike, they are not the stock CB750m rears, as those were far to stiff for the weight. The original bike was around 600 lbs. This is in the mid 300's.
As for the headlight, thats a lens (mid 60's VW Beetle) over the headlight, which is aimed correctly. Look at Roger Goldammer's Nortorius, a Cafe Bike with the same headlight set-up.