18.5 HP Briggs Power?

Take a look at the way a belt driven, self propelled lawn mower works. Drive pulley, idler pulley hooked to some type of tensioner/foot pedal, driven pulley. Cheap.

Or, maybe a centrifugal clutch/chain drive like you see on chain saws or go carts.

Don't forget brakes. 45 MPH is FAST for a homebuilt cart.

Try Comet Clutches

Hi from 58flh/ Me & my partner had a 12hp. briggs&stratton vertical shaft motor! We built a 2wd gocart for his kid, we did this back in 1986! #1 a strong mount for engine preferably steel but a good grade t-56 aluminum is also preferable! a quarter inch piece of alum. is suffice for this 18hp rating! Now the fun part, go to junkyard,first figure how fast you want to go. This is imp. because torque will play a part in off the line driveability!All the way to desired max speed. What I did was figure that in the yards you will find plenty of old rearends . figure what tire hight will be in use then buy a ring-gear and pinion gear to match! The shaft extending from motor can go 2 ways about it !#1 cheap & simple this part should be purchased new! get a centrifical clutch, &dissassemble to put heavyier shoes & springs in it ,reassemble! this is strong & will last quite a few beatings.mount clutch first, some three sixteenth steel, torch, & welder makes short work of this! #2 same as #1 but no centrifical clutch! motor will have to be mounted securely sideways. you will have to add 8inches to the existing shaft,via welding, this will throw the motor out of balance, you have to rebalance the rotating assembly. I dont know how your shop is set. But if you can handle this type of machine-work your-a-o.k. no problems, hardly anty money at all just your time!! After you complete the shaft buy a small or make a flywheel, not to weigh more then 12 to 13 lbs.,again 3 sixteenth steel is good,or 3 thirty-second steel if you cant get the weight right. eighth is to thin & tends to flex a little more then im comfy with. next find dead center of flywheel & make it so it will bolt to the end of the added shaft,add a steel dowelpin or bolt so its locked in place & can not spin! now buy a smallest pressureplate & clutch-disc you can find. there will be grooves in the center of both. horizontilly mill these allowing 4 thousands of an inch for clearance & heat so it dont bind! if you have gone this far you know you need a bellhousing, if you dont make one a early type volkswagon one can be reworked with a drillpress 4 bolts is plenty at 3 eight 16 thread. the throwout bearing i forgot to mention will come with clutch & pressureplate kit. if i still remember it will work right on the 1inch shaft,truthfully that part i dont remember!!! then you use the same ring&pinion set-up! good-luck this is something me &my buddy did for the kids back in the eightys!! You might be able to find a full bolt-on kit today for a few hundred, i dont know. Im just telling you what we did with no money, or very little to spend!!!!! I hope I could of helped you out in some-way from one wrench,do-it yourselfer to another 58flh good-luck

I have repaired small asphalt rollers. They have hydrostatic transmissions in them. I have seem 16 hp Kohler engines used on these. The rollers use a simple chain drive between the transmission and the rear roller. There are also HSD transmissions that incorporate a differential to power two rear wheels.

With a HSD transmission, you would couple the output shaft of the engine to the HSD with a coupler, or belt drive to change the maximum output speed of the drive wheels. You can then attach drive wheels to the output shaft(s) of the HSD. You can then set the engine speed to a fixed speed, and vary speed by the HSD, or use a fixed position for the HSD, and vary the engine speed. Either way, you will get a self lubricating drive system that will also have reverse, and the ability to brake by moving the HSD lever to the reverse position.

Try looking for (well) used rollers, and other construction equipment for a used unit. Good luck.

Please consider a variomatic belt driven transmission. As you find on old Daf and Light Volvo systems. Simple and good and automatic.

You beat me to it. Those variomatic belt driven systems or sometimes called torque converter, system are great and work a lot better than a centrifugal clutch as you start off in reduction and as speed builds the reduction is reduced. Using one of these will get you good starting power and also great top end speed. I have seen these listed on the Norther Tool site.

I would suggest that you not use an automobile transmission. There are many lighter transmission for your vehicle. Many small tractors for home and garden use have simple rubber belt CVTs. For example, the John Deere Gator line of small utility vehicles use a belt with a conical pulley system. They can deliver an abundance of power and can reach speeds of 10–15 mph (16–24 km/h), all without need for a clutch or shift gears. Nearly all snowmobiles, old and new, and motor scooters use CVTs. Virtually all snowmobile and motor scooter CVTs are rubber belt/variable pulley CVTs. You might find a used garden tractor or ATV that you can take the transmission from.

I did six years at a small engine shop in Florida. Go to such a shop and talk to the mechanic about riding mowers, which have just the transmissions you want, vertical shaft on top. Four speed with reverse, belt clutching with idler pulley. I presume that's an electric start motor. The electrics are simple. There's an alternator in the motor, usually. John Deere is good quality. Others will do the job. The axle shafts are simple. You can fake the bolt pattern up to larger wheels.

a lot of the Lawnmower racers use the standard belt drive and transmission/transaxle in theirs. What is modified is the drive and driven pulleys of the motor and transmission. Of course they soup up the motor, but you will probably not need this, since a lawnmower going 70 is a little fast for me....

The pulley and belt change should be good enough for you...

How small (light) is the vehicle? Is it a clown car size like a go kart with a car body or is it a 1/2 scale model T? The combined weight of the vehicle and the operator as well as your 45 MPH top speed will determine how heavy the transmission needs to be. Also the width of the vehicle will play a role if you choose a trans-axle such as a lawn mower uses. If you choose a trans-axle how will the wheels mount? What type of rims/hubs do you plan on using?

A good parts source for projects like this is www.surpluscenter.com I have used them a few times for odd jobs and have been happy with the parts and customer service. Check out Item# 13-1430. Hydraulic brakes, forward, N, Rev. Add a drive from a snowmobile to this and it should do quite well if it can handle the output RPMs needed for the target 45 MPH.

The horse power seems right , but if you are using a verticle shaft motor you are pretty much relegated to a belt and pully type power transfer system such as used on riding lawn mowers and described by the boys .

I suggest you use a horizontal shaft motor to take advantage of the torque drive system descibed by the boys. Its an excellent system and horizontal shaft motors are half the price and available everywhere. The money you get for the vert. motor will pay for the horiz. and half the cost of the torque drive .

Take a rear end & rotate it untill the pinion is vertical. Then run your belts or chains to the gearing & the clutch mounted on your vertical shaft motor.

Good Luck

Doug

Dear Sir:

Don't think that is the best answer to your quest. A horizontal shaft is much more desireable. There is a reason bigger and better lawn and garden tractors have horizontal shafts. They can have the head planed to add more compression should you need it.

Plus, are you sure that the 18.5 HP is adequate for 45 mph? It seems that you would need more like about 25-30 HP or even more. If it were me I would seriously look at something like a small diesel engine from a VW or maybe a larger lawn tractor like a Kubota or John Deere with a 3 point hitch. Those have a bit more power and may be able to do the job better. A junk yard or old farm store often have some engines laying around.

-just my two cents worth.

Sincerely,

Moe