Golf cart based electric motorcycle build.

[woodsmith]

I notice that you are direct driving the drive shaft without the gear box. How are you placing the motor? Off to one side or are you centralising it somehow?
I am building a reverse trike using a BMW K100 transmission complete.


The input shaft is 90mm off centre but the shaft would be 150mm off centre and higher then my prefered motor mount. I am going to use a short shaft but a nice looking one.



The trans gives me a slightly under geared drive for what I wanted, 1.61:1 top gear with a 2.81:1 final drive giving 4.52:1, for my first choice 12" motor so I have decided to use a smaller but hopefully faster 9" motor.


Those shafts look great, though costly!

I was using a similar motor but not having access to anything but a small lathe I had to find a simpler way to make splines.

Turned a blank on the lathe.


Marked out the edges of the splines.


Cut the splines with a 4 1/2" disc cutter freehand.


Fits a treat. (notice the wooden DE bearing cap)


I made three of them in the process of working out how to use the other end.
I settled on this one with a support bearing on the outer end.
I even had to chisel the keyway out with a small cold chisel.


I also used a square of aluminium plate for the DE.



It now drives my tractor.

[MetroMPG]

Originally Posted by woodsmith

Cut the splines with a 4 1/2" disc cutter freehand.

Impressed!

[Ryland]

My motor is going to be off set to the right side by about 7 inches, this gives me enough room on the left side for another battery next to the motor.
Your splines are impressive for being cut free hand, I was going to try to make splines on the mill with the corner of and end cutter but it was not the correct angle, it might have worked for a while but I want mine to be as exact as possible.
I also wanted something that, if it all works out correctly I can make more for anyone who wants one, after all most of the work is in figuring out how to do it the 1st time.

[Ryland]

I haven't done much work on this project in recent months but I'm starting up again now that the weather is getting warmer it's more comfortable being in an unheated work space.
Current part that I am working on is making an attachment ring for the dust boot that keeps dust out of the drive shaft, I'm using the stock dust boot from the CX500 motorcycle but it attached to the engine with a collar that was pressed in to the gas engine, this is not going to work for me so I'm going to make what looks like a very thin spool out of some 2" aluminum pipe to create a flange that the dust boot can then slip over, I had a number of people suggest that I not bother with a part like this, but over time dust and sand getting in to the UV joint will wear it out and I would like this to be as reliable as possible.
The milling machine at my parents house is also in full working order so I can mill basic parts on my own now, this should be helpful in making the battery rack and the last part of the motor mount.
For the battery rack I'm thinking I'll have a center solid rib that supports the batteries and connects to the frame where the engine did, giving strength to the frame, then box it off a bit, have what looks almost like a skid plate between the batteries and the front tire and have it wrap under the batteries and motor, if I set the batteries low enough there ends up being an empty cavity under the motor, this seems like a good space for the speed controller, at some point this week I hope to do a card board mock up of the battery rack and batteries to see how it will really fit together, I'll take photos at that point.
I was also reading about motor options, there are some nice 3 phase brush-less motors out there that will bolt right on, peek horse power of 50hp would match the stock engine altho a 72v motor from a GEM should also be able to handle a momentary peek of nearly 50hp as well, so either way, if I am not happy with the $100 3hp motor I have, a more powerful motor will bolt right on.

[MetroMPG]

Ryland - any chance you're taking pictures of the work as you go?

[bennelson]

Pardon my ignorance...

Is there any sort of gear reduction between the driveshaft and the rear wheel? If so, what kind of ratio?

On my chain-driven electric motorcycle, I am using a 6:1 gear ratio to keep the motor from working too hard. (It's a 48V system.)

A friend of mine has a drive-shaft cycle that he has been playing around with as an electric conversion, but he's been having issues with pulling too many amps.

I would imagine that higher voltage would help with all of that, but I was just wondering what the "gearing" difference is between a chain/belt drive and a driveshaft.

[Ryland]

Originally Posted by MetroMPG

Ryland - any chance you're taking pictures of the work as you go?

Yes I'm taking photos, mostly with my cell phone, but a few with a borrowed camera as well, I also figure once I get it all done I'll take it apart and take photos from start to finish, or get another motorcycle and build a 2nd electric motorcycle.

Ben, no gear reduction, the stock gear reduction on the drive shaft is around 3.09 to 1 if I remember correctly and that is higher then I would want if I was starting from scratch, but that is the other reason that I'm using a series wound motor is that they have better low end torque and I do share that same worry about drawing to many amps, but like you said, a 72v motor and controller should help, or at some point shell out the money and get a 144v motor and controller, there are only a few that I have seen and they cost a bit but they are an option and would bolt right on.

[Ryland]

I'm almost done building the battery box for my motorcycle, it's taking a little while because I had other projects to take care of over the summer, the first version is made out of steel because I can weld steel and it's cheaper then aluminum.
I also picked up a used Altrax speed controller, 48v 400amp controller, should be good enough to get it on the road and see what stock golf cart parts can do.

In other news I met a guy near here who is building an electric Honda Goldwing, he's also using an EZ-Go golf cart motor, of course he had the same issue I had with needing to connect an open face motor that has a female splined stub instead of a normal output shaft, as it turns out, Honda used the same spline on the output shaft from the transmission for the Goldwing as the did on the CX500, the only thing that is not the same is the Goldwing shaft is held in to the swing arm UV joint with a snap ring where the CX 500 uses a 6mm bolt that locks in to a grove in the end of the shaft so it can't pull out, but as luck would have it, that snap ring on the gold wing a redundant part because the shaft inside of the goldwing swing arm has more support.
So just a few minutes ago I get a phone call from this new friend with the Goldwing, telling me he has his motor bolted up and is working on placing batteries, motor runs, rear wheel spins and he's hoping to have something on the road latter this week, max GVW of the gold wing is just over 1,000 pounds, so even with a frame full of lead acid batteries his motorcycle will be 100's of pounds under it's max weight, mine will be pushing it's max weight but should still be under it.

[Ryland]

Photos! sorry for the low quality, my cell phone camera isn't the best after 4 years of being in my pocket and getting stepped on a few times.



Here is the battery box, it's almost done other then two steel plate tabs that go on the top, center, that bolt to the frame, up under the gas tank, these two plates will be 3.5" apart and give space for battery cables to come up from the lower batteries, they are next on the list of things to weld.



Here is how the motor looks in the battery box, almost enough space under the motor for the speed controller but not quite... might put the DC to DC converter under there or just a spot for storage? not sure yet.




Here is a photo of the test fit of the adapter shaft that I designed fitted in to a 1978 Honda Goldwing... Nothing else from my motorcycle design swapped over other then the shaft but the shaft is also the hardest part in my mind to make.

[mechman600]

Glad to see you are back at it! I can't wait to see the final results. I really really want to convert a motorcycle sooner than later. Actually, I want to convert lots of vehicles but I have limited space and a wife who doesn't like seeing "junk" lying around, whatever that means....

Anyway, I'm sure what you learn doing this project will make it easier for many others (including myself) in the future.