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A little off topic, but you are the guys to ask!

OK I know this is slightly off topic, but I know you guys will have some great ideas. Someone abandoned an old Yamaha Riva Scooter at work (it blew its motor on the road in front of the dealership he pushed it in and never came back for it)…

I am thinking about making it into an electric scooter, but I have a few questions for you guys…

  1. This is the big one, can anyone think of a continuous duty electric motor from a car or other device that will A) have about 5 HP (the gas motor was abouy 11hp, but I dont need it to do 60), and B) run on 12 volt batteries?? I was thinking about a trolling motor from a boat, but I have been told they must be immersed in water to stay cool or they over heat quickly. I thought about a electric lawn mower motor, but that’s 120 volts… A starter motor from a car would be great, but its not continuous duty… Basically I want something I can get at a junkyard/craigslist for cheap.

  2. Will the trans on the Yamaha work without the gas motor (IE is it run off the motors oil pressure??)

  3. Anyone ever do this??

Thanks in advance guys !!!

It will take a ton of batteries unless this is just made for a short round the block hop. Many years ago a friend of mine added a 12 volt battery and a Chrysler gear reduction starter motor to a mini-bike that had a trashed engine. It was a hoot to ride but not much for distance and the problem with 12 volts is that amperage draw on that low a voltage while moving a fair amount of weight is that the batteries likely won’t last that long. The transmission is lubed by splash basically so oil pressure won’t be an issue.

The scooter my friend built had an on-off switch on the handlebars. When riding that one it was lean over the bars, flip the switch, and hang on for dear life because there were only 2 speeds; off and wide screaming open. You might need a potentiometer to control RPMs but it’s going to take the mother of all heavy duty pots to do it with.

Interesting idea…
How about a golf cart motor?
In lieu of a large pot, you could probably cobble up a speed controller with a mess of FETs (a variety of a transistor) mounted to a heatsink. A DC motor will have a tendency to stall when loaded if it doesn’t quite have the nominal voltage applied but maybe it would need some sort of feedback into a controller that tells it to apply a voltage to get it rolling to the speed you want - maybe like a pickup on the wheel that tells some ‘smarts’ that the thing is rolling and at what speed. That calls for something like a microcontroller of sorts. Let me know if I can help out in that department, once you get going.

You are about to enter the world of ‘file to fit and paint to match’. Google is your friend. This came up near the top.

One project used the motor from a power chair.

This motor seems to be popular. Hold on for the price!

And you will need a controller. And to pick a voltage.

You don’t need a transmission. So the engine and trans should go. You will have to fabricate something for the rear suspension.
Best of luck.

I’d ditch the transmission, electric motors usually don’t need them, right? I wonder if there are some do-it-yourself EV web sites that’d have some info…

Yeah I have been thinking about this idea for a while now, and want to keep it simple. I don’t want nor do I have a ton of money to spend on this, and I hope the lessons learned let me build a electric car one day (look up forken-swift on youtube and google for an idea of what I mean if you have a second)…

@remcow -I thought about a golf cart (I live near Hilton Head so they are plentiful) as it has everything I need, but I thought everything would be to big and heavy for bike use.

@mtraveler Power chair is a good idea, and should already have a controller and other necessary items. I can always get multiple batteries for more range in that case, but I wonder about speed… I would like this to do at least 35mph…

I also just did some quick research and apparently the motor and trans on the Riva are part of the swing arm, so it will be hard if not impossible to strip it out and still use the swing arm without making another (which I am ill-equipped to do)… Maybe if empty the case, I can still use the basic structure??

You will have to start taking things apart and see what you have. It appears the “transmission” is just a set of gears with the case acting as the swing arm. The actual transmission is part of the engine assembly and uses a centrifugal clutch and variable pulley. Assuming the final drive ratio is acceptable, you might be able to use the existing transmission case but will have to figure out a way mate the electric motor to the case and final drive. Depending on your resources, that could be harder than fabricating a new swing arm.

By the time you got this conversion working, you will have spent more money than the price of a new, factory-built electric scooter…Sell the Riva as a “no title” parts machine and use the money as a down payment on your electric scooter…

Or fix it for more $$$…

I think you’ll find that most manufactured electric scooters run with a hub motor, that is, the motor enclosed in a larger rear hub, which eliminates the need for a drive train. You might find it less complex to just adapt a 48 volt hub motor than to connect to a gearbox, but your swing arm issue could make that impossible.

35 mph is VERY fast for an electric scooter, and I think you’d also have a legal issue, and possibly a safety issue. In California at least, the law defines slower electric scooters as mopeds or electric bicycles which MUST have pedals capable of moving the bike, even if they are not generally used, and are limited to no faster than about 20mph. Such vehicles are NOT required to be registered or licensed, and do not require a motorcycle helmet. Above 20mph, or no pedals, and it’s considered a motor vehicle like any motorcycle.

Three years ago I stumbled upon a cheap Chinese step through scooter which is ridiculously gaudy and poorly made, but it’s truly a hoot to ride. It’s a 300 watt, 48 volt hub motor, which gets me a max speed of 17 mph. It came with a crummy charger which apparently killed my batteries, so for the moment I’m grounded, and the scooter is questionable about being worth the cost of four batteries and a better quality charger, but I’ll probably do it. More typical scooters use a 600 watt motor. Mine had a range of about 20 miles, recharged in roughly 8 hours for almost nothing, and allowed me to avoid starting up my car for local errands where I’d burn half a gallon of gas just waiting at stop lights. The scooter is virtually silent…quieter than an electric toothbrush, and so cheap to charge that I regarded it as free. I was even able to ride with a a passenger…we’re both small, though for mild hills I had to use the pedals to assist. Oh yeah, forget hills if you have a 300 watt motor.

Google for electric vehicle clubs and you’ll find people with the technical knowledge to give you good advice. Converting your Riva may be more expensive than just buying a new scooter, but the fun of figuring it out may be a lot more significant…go for it! And be sure to post updates!

@westernroadtripper Yeah, thats what I am finding out… Thats kind of why I was looking for things I can use for parts… Like the Forken swift guys did only on a smaller scale. I think it would be fun !! As for speed as long as I keep it below 35 MPH I dont think the cops around here will care, I only have about a 3 mile commute to work and the grocery store my wife always has me run to to get what she forgot is only 3 miles the other way… Even if I can only do that it would be worth while for me… Most of my diving is around town, and I only do about 7,000 miles A YEAR on my car… Ohh yeah its very flat around me as well so that works to my advantage.

Keep the ideas comeing !!

This sounds like fun. Go for it.
Personally, I’d be inclined to look for a small gokart engine. I have a great tool supply place near me that sells “real” tools, including grit blast tables, welders, hoists, etc., as well as one-lung motors both horizontal and verticle shaft, but if you don’t have such a place Google is your friend. You can visits the Bell website while you’re shopping…and [ick up a helmet.

I wonder whether you couldn’t use a larger stepper motor…
They are small, quite efficient, can provide huge amounts of torque and won’t stall if you drive them correctly.

Or how about a DC motor that drives a flywheel? Charge the flywheel, get it running at a decent speed and gear it down to what you need.

I don’t know anything about gas to electrical conversions, but I’m a member of some gas savings forums and know there are some people on them that have built electric cars and motorcycles. Go to one of these sites and ask around I’m sure someone can help you out.

How many HP’s in an electric lawn mower motor? Maybe 2 from the cordless ones will do.

There are several companies out there making electric motorcycles, and some of them sell parts. I would buy the parts from them to make things a little easier. Some of them will also sell you batteries for this type of application so you won’t need to use normal lead-acid batteries.

As to ok4450’s assertion it will take a lot of batteries, based on what I’ve seen, this is why gearing is important in an application like this. On some electric motorcycles, the rider can adjust the gearing to get more range from a set of batteries.

Youtube has a lot of videos on this subject.

This one (below) was converted using scavenged materials. It uses four lead-acid batteries, with two of them mounted like saddle bags and two of them mounted where the engine used to be. This isn’t a scooter, but I think it is a 234cc Honda Rebel, which isn’t that different from a scooter.