NEM0 - Electric Dual Sport Motorcycle
I'm quite fond of all of the commercially available electric motocross options, but not enamored with the fact that most of them start at price levels of $7,000 and above. They're mostly aimed at obtaining a near 250cc level of performance, but for my daily use I won't be needing more than 50cc. I don't need to go above 35mph and I don't intend to launch myself over 15-foot jumps.
So for the past week I've been poking around at various options and determined that I can obtain the following for under $1,000.
Top Speed: 35mph
Range: 20-30 miles
Weight: 180-220 lb
Motor: 60v 1kw 1.8hp 3700rpm
Battery pack: 60v 20ah
Build Cost: <$1,000
Rough Design Concept
I intend to make it road-worthy, even though it will be operating within a DMV loophole that prevents it from needing a license plate or insurance. So it will include lights, turn signals, and horn, albeit custom-made ones.
It's finally above freezing for the first time in a month. A toasty 54F. It's so "warm" I was able to work the ice out of the garden hose.
Parts everywhere. The parts on the far right won't be needed (fuel tank, exhaust, muffler, engine brackets).
Frame is pretty filthy.
I can only get is so clean with dish soap, water, and a brush.
I'll have to clean it further by sand-blasting it. But for now it's clean enough to start cutting and welding.
After measuring the frame some more and shopping around for materials I decided to start the CAD work all over again. The first two designs were too cramped or involved fairly expensive materials.
This latest design will be easily made with less than $60 worth of steel (L-channel and 1" square tube) and some sheets of polycarbonate (which I buy as scrap). All while allowing for a wider range of sprocket sizes.
And it will only require me to cut out and replace the small downtube that held the engine and skid plate, rather than having to alter the main fork of the frame.
I've found a set of Dual Sport tires to replace the current knobby tires.
Front Rim: 1.4x19
Rear Rim: 1.6x16
Stock Front Tire: 70/100-19
Stock Rear Tire: 90/100-16
Replacement Front Tire: 2.75-19
Replacement Rear Tire: 3.00-16
It looks like my final gear ratio setup is determined. I will have to double check the diameter of the replacement tire before I order any sprockets though.
Max Motor Speed @ 60V: 3750 RPM
Motor to Trans: 1.7:1 (10t to 17t)
Trans to Wheel: 4:1 (12t to 48t)
Max speed: 35.5mph
I also ordered a ton of parts from TNC Scooters, and major components from eBay.
Money spent so far: [=+2]$507[/]
Haven't done much except measure the motor, then research/shop for sprockets and chain.
As I remembered correctly, permanent magnet motors are definitely not free-spinning when unpowered, so I had to do some thinking about how to add an overrunning clutch cheaply. I'm going to be buying a bike hub that I can cut apart to build my own.
Starting work on the battery rack and frame.
And I lathed some aluminum collimators for the high power headlight LEDs. The wide angle will be angled further downward than the narrow one.
Feb. 24th 2009
I've been really sick for the past week and a half.
Yesterday I cut the end off of the bike hub, lathed it down, and made a bushing to weld into the end of it. I then made an adapter to bolt onto the freewheel.
Once the hub end is welded to its bushing I can bolt the assembly together and the overrunning clutch will be done.
Wow, excellent. I assume those are SLA batteries?
Looks like a great build!
I like it. What was your donor? Looks like one of the larger china bikes.
Like it - you are right that a decent motorbike CAN be made sub $1000.
Last year I bought one of these kids dirt bikes for 250pounds (400 dollars) - Its the best bike Ive got
Its more an adult bike than for kids, its got a 450wat motor and it really is good. Ive never found out who the manufacturer is because theres no makers name on it.
Only problem is its not street legal.
If it had a LIFEPO4 battery upgrade and could be fitted with whatever was necc to make it street legal then I would say it could be turned into a pretty good sub 1000 motorbike.
I've seen those x-motos before. They are fairly popular here [http://www.chinariders.net/] . New swinger bearings and hardware(bolts, etc.) are usually in order before you ride it too hard. I would like 50-100cc performance also. Like to bash around the yard. This spring the finishing touches are going on a Honda XR50 with a 88cc kit and 4 speed. Also upfitting a Razor MX500.
Colin like that ebay bike you've got. Maybe you could repack that battery tray with li-po's.
It looks as if you are going to put the batteries on their side. I wrote to Greensaver about using their batteries on the side and they said they could not recommended this position. They mentioned that during the charging cycle the electrolyte becomes very liquid. Maybe in other gel cells batteries this is less of a problem but check that out before you order batteries.
Looks like a fun project. I built my son a 1200 watt 48V Dirt bike as a modified Razor MX500. I don't have a great place to ride one where I live, or I'd just buy the one in the link below. I haven't ridden that bike, but heard it climbs any hill with ease, and its made out of quality parts. Not $1000, but not $7000 either.
:) :? ) Were did you find that male plug it looks like something that would be usefull for a lot of apps. ? LaTeR
Nice! Good progress.
yeah! looks very nice indeed!
make sure to keep us informed with lots of pictures!
btw.. these batteries look a lot like UPS-batteries, maybe that's why you got them cheap?
Hey Cap'n, that's all we get for today? let's get a look at the tires you'll be using.
Very perfect ! Expect your complete pictures .
please discribe that hub motor, you know ?V ???W no load rpm, "brushed or brushless" how much $$.CC how do we get holt of you ? LaTeR