Lots of people want motorized scooters! But, for the most part they are to expensive! I have searched high and low for a good motorized scooter site and I really couldn't find any solid plans that I didn't have to pay for!
So I decided to make my own from scratch, and post my plans on the net for people to see! I love to build different stuff that have motors so here you go!
MY DISCLAIMER: THE WORK DONE ON THIS SITE AND ON MY SCOOTER ARE THE THOUGHTS AND ACTIONS OF MYSELF, FOR OTHER PEOPLE TO LEARN FROM OR TRY OUT. I AM IN NO WAY RESPONSIBLE FOR ANYTHING THAT HAPPENS TO YOU ON YOUR SCOOTER, WHILE BUILDING IT OR YOU WHILE SURFING THIS SITE! (happy scootin')
--Small engine ( 20cc up to 80 cc ) will work the best for this job. Something that spins horizontally like a weed trimmer, blower, chainsaw or a real motorized scooter engine would be the best because the are small and have high rpm's. (revolutions per minute) The best engine's in that list above are weed eater or chain saw because they have centrifugal clutches in them already (most of them do). All chainsaw motors will have a clutch but to check if a weed eater motor has a clutch, look at the top of the shaft that comes out of the engine. If there is a good bump there, then most likely (not always) the engine has a pre-maid clutch in it ( in between engine and black handle is the centrifugal clutch ) ! If not you can take it to an engine store and they might be able to fix you up with a go kart clutch that fits your shaft size on your motor...( this is what it looks like )
--Pre-Made or built yourself scooter. This has to be a big scooter with big rubber wheels (example of a scooter that you CAN use), not the little metal one's where you can hardly get 2 feet on the deck. (example of a bad scooter that you CAN'T use) If you buy a scooter it will be around 150 dollars to get a nice one. You can find a cheaper scooter in a junkyard or pick up a used one off of someone at a garage sale or something. If you want to build your own scooter than you can design the scooter around what you want to do with it. Wide, narrow, long, short....it is up to you! Something like this design would be good though! I don't recommend you building your own frame unless you have a good welder, the parts and you know what you are doing!
--Gear and Chain or Spindle Drive. For this scooter you will need 2 gears ( 1 on the engine and one on the wheel ) And you need to connect them with a chain. If you want to use a belt and pulley you can do that but you need more room for that, and the pulleys have to fit on the engine and the wheel (at times maybe more difficult and there is more power loss with belts because they don't grip quite as well, unless the belt has teeth in which case you could use a chain drive instead). Spindle drive is with no gear or pulley. The engines drive shaft sits right on the wheel. I will get into all drive methods further down the page!
--nuts and bolts. you will most likely need nuts and bolts to mount your engine, and put stuff together, so keep that in mind. You can get them at your local hardware store! ( very cheap$$ )
--Scrap metal. This is used for the frame on the back that you mount your motor on and other fabrications. Also could be used to make a seat!
--Money. you will need a little bit of money for this because you have to get a few welds done and for other odds and ends... I guess, I know I did!
Gear Ratios and Wheels (and tires)
Problems That Arose While Building my Scooter( This is basically what not to do and how to fix it if you have done it already. On my scooter I had a bunch of problems that I could have fixed before I even started. So really this is a part of the site where what I said above doesn't count. This was is better. What was said above was how I built it to start off. This is more of a revision of what went wrong in the building process.)
Links
Once you have picked out your motor, whether it be a chainsaw (this is my engine 32cc), roto tiller, or weed trimmer, you have to get it running! If you got one from a junkyard chances are it isn't going to work. So you need to probably redo the carburetor, either clean it, overhaul it or buy a new one! Unless you know what you are doing I would suggest going and getting it done by someone who does. Once the Carburetor and whatever else needs to be worked on is done, you can put some gas and oil into it. Most small engines like these are a 2-stroke which means that you have to put in a gas-oil mix. Usually 50:1 or 45:1 is the ratio of gas to oil in the mixture. Although, some are 4-stroke which means that you have to put in gas and oil in to different places. But check on your engine yourself or with somebody just to find out for sure what kind of engine you have and where the gas and oil should go or what the mix is. Next what you can do is clean the engine up on the outside (case, started cord, metal...) Just use a rag and some heavy duty cleaner to get the grime and stuff off. Make sure the engine works and free of grime, and you are done!
--Bike Chain and Bike Gears. I used a chain because it took up less space (width) and it seems to provide more power on rough surfaces! A belt might slip a little bit. I got my gears and chain off an old bike that I had lying around. This bike was a kids bike with only 1 gear on the front and 1 on the back so there was no changing gears. It was also a "pedal backwards for your brake" bike. To get the back wheel of a bike, just undo the nuts and bolts. Remove the chain off the back gear and pull the wheel right off! There will be more bolts and stuff on the gear on both sides. Undo those and pull the whole gear unit out of the center of the wheel. It should look something like a cone with a gear on top. There will be different clips for every gear, but on my gear there was a round cir-clip holding the gear and cone together. It was located in the middle on-top of the gear. You can just pry it off with a a screw driver. Every gear is different, just work with it for a bit to get the gear off! Then you are left with just the rear gear with a hole in the middle which is fine! Then you have to take the big one off from the pedals. To do that you can hack-saw the pedals off, or you can crack the little metal or plastic casing on the outside of the round joint in the middle of the bike. When that is off, you will be able to see some bolts and some other metal. Undo the bolts and pull the whole pedal mechanism right out of the round joint ( you have to break the foot pedals off first to get the whole pedal unit out, I think! ) Take the gear off of the steel pedal ( without bending ) and set it aside. You now have two gears. And for the chain, you can use the same chain that was on the bike to start with!
--Spindle Drive. Spindle drive looks like this. This person just has there driveshaft from the flywheel (or it might be on the other side I don't know) resting right on the wheel. They have taken part of the engine case, cut it off and has extended the drive shaft right on the to the rubber on the wheel. There are advantages to this. It is easy, very light weight, good for beginner scooter makers and gives a very good gear ratio. On the other hand it isn't good because it tends to slip a fair bit, you need a fairly slick tire to do it and you have almost no opportunity to mount a clutch PROPERLY. But if you want give it a shot.
--Belt drive. Belt drive is stupid. Don't! The only reason you would use it for is if you absolutely need a clutch and you couldn't get one so you would use it to a jackshaft as an idler. (idle pulley) The idea behind this is there is a pulley on the jackshaft and a pulley on the motor. The belt on these pulleys is fairly slack until a 3rd pulley comes in on an arm or something and pulls the belt tight. This make the engine turn the jackshaft. The jack shaft is connected to the wheel by a chain or is rubbing right on the wheel like spindle (friction) drive.
--Jackshaft. This isn't a drive type, but more of a drive method. A jackshaft looks like this and this. The idea behind a jackshaft is to get a better gear ratio. Many scooters have 8 inch wheel or something and they cant fit a huge gear on the wheel to get a proper gear ratio. So what it is, is a solid piece of round steel that has as big a gear on it as you can fit. On the engine you have the smallest gear you can get. (for a bike gear its 11 and for a go kart gear I think it is 8) A chain (or belt) drives the small gear (or pulley) on the engine to the the big gear (or pulley) on the jackshaft. From the jack shaft another chain or belt is run from a gear or pulley on the jackshaft to a gear or pulley on the wheel. Then you get a nice gear ratio. This helps a great deal when you want to change your gears or whatever frequently to get different ratios. It is sometimes costly and difficult to build and must be very precise. But if done correctly can be a very useful tool.
Gear ratios on a scooter are probably one of the most crucial things to be done. This effects your top speed, your acceleration, your torque and your ability to climb hills. This is how your gears should be set up. Get the smallest gear available to you and put it on your engine. With a clutch or without a clutch is up to you. Then if you have a 12" wheel put the biggest gear on the wheel possible. You can also use a jackshaft and gear it that way but it is complicated. So what you are trying to achieve is a ratio anywhere from 4:1 all the way up to 12:1. Anything lower than 4:1 will not take off very well and anything over 12:1 will not have very good top speed. There are exceptions to every rule though. Your scoot may be very light and you could go under 4:1, I don't know. You scoot may be heavy and you have to go over 12:1 to get a good acceleration and decent top speed, I have no idea what your setup is and what it weighs. Whatever it is thought make sure that it is controllable for you. Not to fast and not to slow! Just right.
--Wheels and Tires. On my scooter I have 12" plastic rims with grippy pneumatic tires. It came with had plastic rims but I switched it out for a $12 (Cdn.) metal rim that could be welded to. I don't think that a jackshaft is necessary for a 12" wheel but if you want go ahead. You should be able to fit a good size gear on there. If you have small 8 inch wheels than a jackshaft is almost a must. That wheel is just too small to get the proper gear ratio without one. If you have 16 inch wheels than a jackshaft is not a necessity, maybe you want it but you can fit nearly every size sprocket on there that you want without coming close to the rubber tire. Now that the gear talk part of the wheel is done with lets talk about a solid slick tire vs. a pneumatic gripped tire. By the way, pneumatic is just a fancy way of saying air filled. Solid slicks are good for spindle (friction drive) but are not good for much else like on rainy days, in sand or gravel. They also ride a lot less smooth than a pneumatic tire. An air filled tire rides a lot smoother tends to have more grip because they have treads, are less used for spindle drives although can be used, have more traction in the various elements (road, off road, dirt gravel etc...) and are more used for belt or chain drives. My scooter has 12 inch air filled tires because I am using chain drive.
Now comes the tricky stuff. We have to do 3 things: make a frame for the engine to sit on, mount the small sprocket onto the engine, and mount the big sprocket on the to the wheel.
Making the Frame (for gear or pulley drive). To make a frame for your engine to sit on you have to take into consideration your engine size and your scooter size. If you have a small engine and a small scooter than you are going to want to make the frame as small as possible. The frame depends on the following: engine size, scooter size, space you have from where you stand or sit, to the back of the scooter, and rear tire size. On my Scooter I had approx. one foot, from where my seat was to the very back of the rear forks. So I had to get a small engine and a small frame. My tire size was 12 inches. My frame had to be 1 foot long, had to be higher than the wheel and had to support a lot of weight. Yours might be different. the height of the frame doesn't matter if you don't have any suspension ( shocks, springs ) at the back as long as its above the tire (you might want to leave a couple inches above the rear tire because of mods that you might want to add later, read on). If you do have suspension, then you will have to allow the frame to be higher than when the spring or shock is compressed. The frame should be about 2-3 inches above the highest possible place the wheel can move to. If you do have suspension then the chain will need a de-railer. This is the springy part on a bike by the gear changer that keeps the chain tight. Any ways, most scooters don't have suspension at the back anyways so don't worry about it! On your frame you should have a flat plate at the top for the engine to sit on and four legs WELDED to the rear. For this job screws, nuts, bolts or nails wouldn't hold the frame on properly. Sometimes, bolts will work alright but I prefer welding way more than bolting and it creates a stronger joint. The whole frame has to be made out of steel. Aluminum is ok, but steel is way stronger! And if you want a jackshaft then just make room on your frame for one and run the appropriate gear of belt to it, then run another chain or belt down to the wheel.
--Spindle Drive Mounting. To mount a spindle drive motor it must be beside the wheel. Either on the left or the right it doesn't matter. But what does matter is which way your engine spins. Put it the correct way to drive the scoot forward. Mounting it can be difficult because you cant really build a frame for it. 2 idea are: weld a piece of plate steel right to the rear fork outwards. So that it looks like this. On top of that put another piece of steel plate on a hinge. Mount your motor to the piece of plate on the hinge. This way to can lift your motor up to start it. Have some heavy duty springs to pull the motor back down when you want to drive. This is sort of like a clutch system. System 2 is having the motor permanently mounted to the the frame with no move at all. This way there is less chance of slipping because the drive shaft can't move at all. Use L-brackets or something to weld to the frame. Put your L-Brackets in under your case bolts of your motor's casing. Now you can weld them to your rear forks
Mounting the Big sprocket ( gear ) onto the wheel: BOLTING METHOD: to mount the big bike gear on the rear tire you need to have a certain type of wheel: you either need to have a metal wheel where you can weld your sprocket onto a hub, or you need to have a very strong plastic wheel that already has bolt holes in it or that can be drilled for bolt holes. My scooter had a very strong plastic rear wheel. There were 3 holes in it already that had been there for holding on a bearing covering plate. I took those off with a screw driver and found that the holes went right through to the other side which was a good thing. I went to a hardware store with my wheel and found some high grade stainless steel bolts that were long enough to pass through the holes. Along with the bolts, I bought some small washers and locknuts. You must have washers and locknuts. The washer keeps the bolt from pulling through the holes on the other side, and the locknut is a nut that has a little plastic ring inside that keeps the nut from loosening when you don't want it to! Lock-nuts have a tight fit and you can't spin them on by hand you need a wrench or ratchet so make sure you get the right ones!!!!! Once I had all the hardware I needed for the back wheel, had a little steel bushing made from a machinist. It was round and sat in the middle of my gear right on the axle around the bearing. This kept the gear centered at all times. It also was far enough out to keep chain from rubbing on the tire ( very important ). So now that the gear is on the bushing and on the axle I drilled 3 holes in my gear that lined up exactly with the 3 holes in my wheel. I used those bolts to go from one side of the wheel, through the holes in the middle and then through the holes in the gear! I then put a nut on it and the gear was being pulled by three bolts onto the bushing, and it was centered! NOTE: The head of the bolt should be against the gear and the nut and washer should be on the other side, this is where you tighten it from, the nut and washer. Also the nut should be tight, not to tight so that the plastic cracks but tight enough so that the gear doesn't move at all or the nuts don't fall off! )
--Welding your gear on. If you want to weld on your gear you need a steel metal wheel. A good way to get it centered is to use washers. Tack some washers in the middle of the gear where the hole is. If the washers don't fit you can drill the centre hole of the gear out so that a washer does fit or devise another way of doing it. You could get something machined I guess. Anyways, then put the gear on the hub. On a bike wheel (what I used) I took the bearings and the axle off and then welded a washer to the middle of my gear. I then ran a bolt temporarily through the washer and through the wheels hub. I welded the gear on and then removed the washer and the bolt. Voila, your gear is centered.
Next we have to mount the sprocket to the engine. If you are using a weed trimmer type engine with a clutch, then when you take the long shaft with the spinning head at the end off, and the plastic case over the clutch off, you will see the bell housing if you have a clutch. The bell housing is the free spinning part that centrifugal force engages at a higher rpm. You can weld your sprocket right onto that. But if you are using a chainsaw motor like I did, then you will have a little bit more of a difficult time getting a sprocket welded onto your engine. You will have to go in between the bell housing and the motor to find a spot to weld to. There will be a little shaft with a gear here that the chainsaw chain used to run on. Either get that taken off or work around it. Doesn't really matter as long as it works. Weld your gear on here and you are good to go!
Now, for brakes. The best kind of braking system are disc brakes, then clamp brakes, then v-brakes, then the old caliper brake. Most scooters that came from the store have caliper (looks like a U upside down) which will do fine. If you can get some better brakes though, it couldn't hurt, but these will do. The best system would be 2 brakes, rim. If you have all your engine and stuff in the back and you are going pretty fast, and you have to stop quickly, and all you have is your front brake, you will do a face plant into the pavement! So back brakes would be very helpful. As long as your engine isn't free-wheeling ( like on a bike when you go down a hill and the pedals don't move the gears just click, but when you start to pedal the bike goes faster, that is free-wheeling ) then when you slow down the motor rpm the scooter will slow down too. So basically 2 sets of brakes are the best, 1 back brake is ok, and 1 front brake is usable as long as your engine isn't free-wheeling! If you gear covers the hole rim and you have no spot for your rear brake, then just have a little lever of something to rub the the tire. The brake pads on brakes come off, so you could also use a set of caliper brakes or any kind of brake with no pads rubbing right on the tire as well.
As for your throttle goes, every scooter throttle has the same principal in mind. Make the lever on the carburetor move! Basically because every engine is different I will talk in a general form. If you are using a weed trimmer or something where you can visibly see and move around the throttle control on the carb with your hand then it will be no problem to see how you hook it up. It will be easier if you have the handle still on the engine (if its a weed wacker or something) because then you see exactly how it hooks up. If you can' t see the carb or the arm that opens and closes the throttle than you will have to use the hand throttle that was on there already. Just find a way to move that lever up and down! As long as your throttle control on the handle bars moves the carburetor throttle than you are good!
Problems That Arose While Building my Scooter
My main problem was the rear wheel. I never seemed to get the perfect wheel for the job, some were to wide, some were not the right size etc... So I finally went to a place that sells castor wheels (on the bottom of a dolly or a hand truck) And used one of those. I got mine from http://www.algood-casters.com/ and it was a full pneumatic, good quality rubber, steel rim's and hub, with a hub and internal ball bearings. I welded my gear right to that hub on the side and then it worked great. Next was the throttle control. The way that my engine was setup, I couldn't quite get at the carburetor for a direct link to the throttle body control. So I had to use the hand trigger and hook up to that. It works ok but I have to do a lot of really fine tuning for it to do so!
Some extras that can be put on your scooter are the following:
Under carriage lighting
N.O.S. (or a different form of it ie: whip cream can, nitrous bulbs and dispenser they have at coffee shops etc...)
headlight
Radio
Horn
Tuned exhaust pipe (very cool)
Smoking exhaust (also looks really good)
Custom or performance air intake (air filter made for scooters or get a "Valve Breather" from EBay or k&n performane or just off a normal car)
Chrome rims
better tires (more grip or slicks or whatever...)
Racing piston ( or a whole bore and stroke job)
Port polish
Turbo or Supercharger
Custom or Dual exhaust
Suspension (springs, shocks...)
High gloss paint with numerous clear gloss coats to make it look like a factory job
Wider rear forks for a wider wheel. (will be done soon)
