Go-ped scooter: How large an engine can be placed on one?

I'm looking for information about replacing the usual 50cc and smaller engines on one of these with something a bit larger. Maybe the 10-15 horsepower range, so say 100-200cc.

I've come across videos about people powering manual wheelchairs by attaching a go-ped scooter to it.  I'd like to see about doing this and upping the speed to about 40mph.

I'm a large person and could probably use a bit extra power over a stock engine. Also, a four stroke would be preferable to a two stroke. Adding oil to the fuel is a nuisance.

 www.youtube.com/watch

http://www.youtube.com/watch?v=7nSA_uKpGpY

sort by: active | newest | oldest
PKM7 years ago
Wait... do you want the go-ped to go 40mph, or the wheelchair?  I'd say either one is a little bit insane, but the wheelchair is the more insane option.

If you really need that much power, there is an Instructable involving making a three-wheeled kart using the back end of a moped with the transmission intact.  That could work but it would be messy.
Lokisgodhi (author)  PKM7 years ago
I've looked into building a vehicle from a moped and a go-cart frame. The big problem is that there's no front brakes and the only way to get some is to use racing cart brakes which are in the $400-600 range. Also, you'd need to register and insure the vehicle.  The size makes it a bit difficult to store as well.

I want the go-ped AND the wheelchair to top out at 40mph.  I don't intend to do that all the time, I'd want to have extra power for hills and getting out of the way in an emergency. If that gets scary, I figure I can install bicycle discs on both wheels of the chair, augmenting the brakes substantially. I can also gear it down a bit too as well.

As you can see in the video in my first post, the go-ped/chair is claimed to go in excess of 30mph with a fairly conventional looking go-ped. 

In another video I found of a different chair build up, the chair can exceed 40mph. It uses a 165cc mill.

www.youtube.com/watch
http://www.youtube.com/watch?v=OSHZhgram2E

I don't like the idea of having such a short wheelbase, using the original wheelchair front wheels for steering, powering the chair's wheels or not having brakes.  You're looking at squirrelly handling for sure. No brakes is insane. I'm certainly not going to use this as a model. I do like the engine size though.

Back to my concept. I see the go-ped/wheelchair as a miniaturized variation of a motorcycle with a mtcvoyager installed. 

www.mtcvoyager.com/

I'm a large person and with me, the chair, the go-ped and a gallon of gas it'd be pushing 450lbs, so 10hp would give me a 45lb/hp power ratio.  
 
I'm not going to start off with a big engine. Logically, the correct way to proceed is to install the chair on a stock go-ped, test it and then make upgrades. 

Another option is to make my own go-ped. Build a go-ped style chassis using bicycle wheels and disc brakes.  Since I could then use larger diameter wheels and a longer wheel base, it would handle better  at speed and would allow for brakes fore and aft, as well as on the wheelchair itself. Four wheel disc brakes would be great for stopping. 
Lokisgodhi (author) 7 years ago
The thing is, souped up engines sound like a lawn trimmer without an exhaust system.  That's why I'm looking to put a larger engine on it. I'd like to keep the noise level down. Souped up engines also generate power at the expense of torque. 

I'm trying to find a way of doing this with a minimum of drama. As I'm using this to power an powered wheelchair, which I have a prescription for from my doctor, I'm not going to be registering it with the DMV. 

Since states' powered wheelchair laws make no mention of how the wheelchair or mobility device can be powered, I'm interpreting this as saying an ic engine is allowed. I'll back that up with a ADA law suit and a internal affairs complaint against any cop who bothers me. That's the advantage of being 43 and walking with a cane and not fifteen. 


As lemonie said about self mixing two strokes that might be a better option for size and weight, plus with a decent exhaust tuned one you don't need as mush displacement...

If you were really looking though it might be easier to mate a generator/compressor/etc. engine with a gearbox from something else since they're relatively compact.

There is also the option of those mini motos, not sure on displacement but they hit around 50mph and there's a relatively cheap supercharger that can be fitted for extra oomph.  
lemonie7 years ago
You could look for a 50cc moped/scooter power unit, CVT separate oil and fuel tanks - no premix required.
Upwards of that, I'd still say moped/scooter CVT.

You will need to check the law though, you're most likely to need the "paperwork" for running it on the road, and won't be allowed to run on a pavement (sidewalk)

L