Topic: Man, you guys are going to kill me.

[Sheik Yerbouti]

Due to some family tragedies and school pushing down, my motorcycle went to the back burner for going on a year now. During that time I worked on an electric bicycle for a school project, designing and building a working prototype in less than three months. That's when I got the idea to scale the project up a notch and convert my CB750.

I started selling parts locally to get some funding for the electric components. The system for converting a motorcycle is absurdly simple. There's batteries, a motor, and a controller that tells the motor to do stuff. Everything else is security measures and controls. For a motor I'm using a separately excited DC motor, which means that I have the ability to do regenerative braking. This isn't going to give me much in terms of a range increase, but it'll mostly help as an additional brake. I'm planning on a 72V conversion which means 6 lead acid batteries. The motor I have is a very capable one, so when new battery technologies (and lower prices) are introduced into the market, I can keep my motor and get increased range and speed (due to less weight).

I'm hoping for a bike capable of highway speeds (70 mph or so) and a range of 20 to 30 miles to a charge with my old (and cheap) battery technology. Down the road I plan on switching to lithium or some other technology.

I don't plan on making it a hack job of a conversion. It's not going to be bolted together angle iron or anything like that. I want to use this as an opportunity to doing a fresh take on a classic bike. I have access to CNC machines as well as a laser cutter, so I can do some creative things to make this bike come together. I realize that this is a SOHC4 forum, and this bike will have nothing really related to that, but I'd like to keep you guys updated and use your collective knowledge because I know I'll need it.

I'll uploaded some concept sketches sometime tomorrow. If you guys have any questions or want to call me a idiot go for it.

[sangyo soichiro]

Maybe you'll end up working for one of these companies... 

[shaunzo]

that sounds awesome!  i hope you start a build thread.  i will follow closely...i am very interested in doing this myself and an electric motorcycle is on my list of builds for sure.  can you give me a couple of retailer names for the motor, controllers, and batteries?  thanks.

[Old Scrambler]

I was at the Bonneville Salt Flats when the electric bike in a Suzuki GXR chasis ran at over 150 MPH........a cool custom CB750 conversion may be the only way we can keep these bikes on the road in a few years.

[theofam]

subscribed!  I've been talking with my 13 year old son about how he should focus on math and science.  He and I already stuck a 150MPG motor on a beach cruiser this summer, so he now thinks it would be cool to build an electric motorcycle.  However, I'm an electrical goober; so, I'm truly interested in what you end up doing.

[Sheik Yerbouti]

I watched the trailer for Charge earlier today. I've been cheating on this forum with elmoto.net which is a forum dedicated to electric conversions/racing/new electric tech.

shaunzo

If you want a primer for all of the nitty gritty details of going electric, check out the "Stuff I Learned" entries at this blog.

http://evmc2.wordpress.com/

It's a really good primer for this. One thing you have to deal with when doing these conversions is keeping your expectations realistic. If you ride like a hooligan your bike won't go as far between charges, and new battery technologies are expensive and confusing. But it's comforting to know that everyday the world seems to be taking strides towards electric vehicles.

[BobbyR]

Fantastic idea!  I work in Rail Industry and all of our Trains use regenerative dynamic braking and it work well. Today we use AC motors, but we also have the room to use sophisticated inverters and propulsion/braking control units to accomplish all of that. Most People don't realize that electric motors deliver full torque at start up, so they can get off the line really well. Good luck on your project, and keep us updated.

[my78k]

I think it's a great idea! No one will kill you...as was mentioned earlier it really may be the only way to keep these things on the road!

Dennis

[Alan F.]

I spotted this one at Rice-O-Rama in september, very cool.  Notice the cool air intake and the sprung solo seat. This thing used every bit of suspension travel when he rode it out onto the grass, must be heavy.  I think it started life as a CBR?

Light and strong certainly are requirements on a bike like this, billet everything, titanium bolts, hollow axles, plastic fenders, carbon fiber etc... make every ounce count towards increasing range. And then there's aerodynamics...

[DavePhipps]

Cool idea, and I'm relieved that you will be trying to make it look good. There are so many fugly ones out there that almost hurt your eyes.

[DavePhipps]

one of my favorites

[Sheik Yerbouti]

There's a quick sideview of what is bouncing around in my head. The panels with the bolts (represented with all those little circles) will be removable, so I can quickly access the batteries/controller/etc. This bike is going to be much thinner than before from a top view, because the frame is the thing that hangs out the furthest, besides that little electric motor (the big circle).

To cap front and top I want to use sheet aluminum that I am going to get milled, so it will have holes for instruments and connectors milled in already. I'll add some color soon and get a different view so you get a better idea.

I am concerned about weight, which is why I decided to go with fairings made from laser cut acrylic, but I also need to create a skeleton structure to hold the batteries in place. The most obvious way is to use steel angle iron (which I would spot weld). Is there anything else that I could do that would be lighter and require minimal welding and fabrication?

[754]

We would have set up a contract, had you done this to a KO..

 but.. best use of a 77/78 ..ever........

 Keep in mond aluminum is 1/3 the weight of steel, think about that,... plus you can mill out plate with woodworking tools, ie jigsaw and router.. and then skip plating or painting.. yet still look very good..

 Good Luck..

[Sheik Yerbouti]

Haha, yeah, I didn't feel very bad sacrificing my K8. I'm more of an electronics geek than a mechanic anyway.

[Sheik Yerbouti]

Starting to bring it into 3 dimensions. I ran out of time today to finish it, but here's the beginnings.

[fmctm1sw]

This reminds me of two things.  First is my own electric car kick a few years ago.  Actually thought about doing a converison on a Geo Metro.  It also reminds me of that Youtube video that was something like "world's fastest electric motorcyle" or something.  That guy took off on a wrecked into a car...    

*edit*  this: 

[unitedguitar]

You could use carbon fiber to build the battery structure. Very light weight and strong enough to hold your batteries. Set it up right and it can be made into one big piece.

Love the name by the the way.

[Sheik Yerbouti]

You could use carbon fiber to build the battery structure. Very light weight and strong enough to hold your batteries. Set it up right and it can be made into one big piece.

Love the name by the the way.

I've never played with carbon fiber ever, but I've tried fiberglass before and it was a pretty nasty process. That's part of the reason why I want to lasercut my fairings instead of fiberglassing.

[unitedguitar]

I have done some fiberglass work and it can get very messy. If you are open to the idea of using carbon fiber they make a carbon fiber that is pre-impregnated with resin so that you don't have to slather it on like fiberglass. There is also a product called hyper fiber that you can get with wires woven into that help it keep the shape you want it to be. It comes in dry and pre-impregnated versions and various roll sizes. It can be a little expensive but it could work. If you're not up for the experimentation then aluminum is probably the way to go.

[Alan F.]

If you are open to the idea of using carbon fiber they make a carbon fiber that is pre-impregnated with resin so that you don't have to slather it on like fiberglass. There is also a product called hyper fiber that you can get with wires woven into that help it keep the shape you want it to be. It comes in dry and pre-impregnated versions and various roll sizes. It can be a little expensive but it could work. If you're not up for the experimentation then aluminum is probably the way to go.

I've seen that somewhere around here, you mold the sheet to your part or to the shape you need then you peel off a backing sheet and leave it out in the sun for a while or set it under a UV source and the carbon fiber sets up just right every time. I'll search around for a minute and see what I can find. BRB

Nope, my search-fu isn't strong this afternoon. Time to crack a beer and go work on a project.
Alan

[unitedguitar]

Here is one type of it. This all has the wire form in it.

http://www.percyshp.com/store/fiberglass-composites/wired-twill-rolls/cat_1270.html

Enjoy the beer.

[Alan F.]

Here is one type of it. This all has the wire form in it.

http://www.percyshp.com/store/fiberglass-composites/wired-twill-rolls/cat_1270.html

Enjoy the beer.

Yup, that's the stuff! Found it: http://forums.sohc4.net/index.php?topic=70843.0

[Sheik Yerbouti]

Finished concept sketch with flat planar access panels. This would be super easy for me to make.

[unitedguitar]

Very cool. Can't wait to see the real thing. I have been thinking about doing an electric bike for a while but I don't really know that much about electric motors and all the components it takes to make one work in a bike.

[Sheik Yerbouti]

To tell you the truth it's not that hard at all. If you can sort through the wiring diagram of your bike you could easily figure out these drive systems. The hardest thing is picking the components, but some places piece together "kits" that make the process a lot easier. But keep your expectations realistic or things can get expensive fast. I was lucky enough to find my motor second hand for a good price.