Want to build custom mini trike, need advice.

[riverrat]

So like I have all these parts lying around, and thought how funny would it be to make a trike using a weed-wacker motor, and some bicycle shocks.

I could run the wacker motor on alcohol, hook up a tuned pipe, and get maybe 2-3 hp out of it.

I am stumped when it comes to finding a rear axle. Was looking at some go-kart axles, but I am not sure how I would make them work.

I don't want to get too crazy with the price either.

I have my own welding equipment, and will make my own chassis.

So I am open to suggestions on what to use for a rear axle, and how to hook up hubs, brakes, and sprocket to it.

Kind of like a pocket trike?

[cr480r]

I would use a motor from a belt-driven cut-off saw... they are usually around 6-7 horse...

[riverrat]

I would use a motor from a belt-driven cut-off saw... they are usually around 6-7 horse...

Oh, there are many ways for me to get more HP, but I was thinking very small, and cute. For my son, and to play around with. There will be room to increase HP if the chassis and everything hold up.

The motor in those saws, are probably 80-100cc's. And pretty hard to come by.

The weed wacker motor I have is 31cc's, has a pull start and a clutch on it. Easy as pie. The whole bike can weigh less than 50lbs, and with a 60 lb rider, 2hp would be fun.

Still need a rear axle.

I was thinking about the go-kart axles, and I don't think they are meant to be suspended in the middle, and would probably fold.

Maybe I should just look for the right heat treated steel. Have the keyways for the wheels machined in, and weld something on to it, to mount a sprocket. Could drive it with the bicycle chain.

This is all not going to happen very soon, but I figure, start collecting parts now, and maybe by the winter.

[team-red-rider]

i got an axle assy from a 110 u could prrly use?

[rugabugadouglas]

get a old lawn mower axle out of a john deere there differental and have chain drive there about 3" around and 6" long as far as the diff looks and the axles are 3/4" shaft

[riverrat]

I think the 110 axle may be too wide for what I want to do.

The John deere axle, has a differential attached to it?

[RedRider_AK]

Use a 70 axle. If you want, I can probably sell you mine cheap. But that might be too heavy. But that would mean you'd have to use the 70/110 carrier too, and that's a little heavy. UHhh... I don't know what you'd use.

More on this: I made a mini-kart out of my sister's Kitty Cat engine (60cc 2-stroke, single-speed clutch) and an old Radio Flyer pedal-powered car. Extended the frame, fabbed up engine mounts and bolted an old plastic school chair to the frame, hooked some vice-grips to the steering stem, and made an over the shoulder throttle cable. That thing RIPPED for a single-speed 60, it probably went close to 20 mph topped out and the kart frame was so light (probably 5 or 6 lbs without engine, maybe a total of 30 with the engine, probably closer to 25 or so) it would do a burnout and shoot "roost" all the way up to it's top speed. I remember I tried to ride it like a motorized skateboard once, fell on my ass and got road rash and dirt embedded in one cheek LOL. I still have that dark blue streak of scar.

Why don't you make it a pocket-bike instead of trike? It'll be fun and maneuverable. Use a fully-suspended 20 inch mountain bike, for the suspension, forks, tires, etc. Custom-fab your own engine mounts. I'm actually planning something very similar myself, maybe with the same Kitty Cat motor

[Dirtcrasher]

I buy a hunk of 01 steel .750 or .875 and mount it in a Bridgeport cutting a .1875 or so keyway for every drive component. Then I'd broach my own key slot machine and weld up hubs for everything.

[riverrat]

Use a 70 axle. If you want, I can probably sell you mine cheap. But that might be too heavy. But that would mean you'd have to use the 70/110 carrier too, and that's a little heavy. UHhh... I don't know what you'd use.

More on this: I made a mini-kart out of my sister's Kitty Cat engine (60cc 2-stroke, single-speed clutch) and an old Radio Flyer pedal-powered car. Extended the frame, fabbed up engine mounts and bolted an old plastic school chair to the frame, hooked some vice-grips to the steering stem, and made an over the shoulder throttle cable. That thing RIPPED for a single-speed 60, it probably went close to 20 mph topped out and the kart frame was so light (probably 5 or 6 lbs without engine, maybe a total of 30 with the engine, probably closer to 25 or so) it would do a burnout and shoot "roost" all the way up to it's top speed. I remember I tried to ride it like a motorized skateboard once, fell on my ass and got road rash and dirt embedded in one cheek LOL. I still have that dark blue streak of scar.

Why don't you make it a pocket-bike instead of trike? It'll be fun and maneuverable. Use a fully-suspended 20 inch mountain bike, for the suspension, forks, tires, etc. Custom-fab your own engine mounts. I'm actually planning something very similar myself, maybe with the same Kitty Cat motor

That was funny story about the scar, sounds like something I would do.

Pocket bike? Come on, this is 3wheelerworld, we are surround by 3wheel freaks here.

I want to do a 70 also. I don't think will work either. The problem is that the trike has the axle supported in the middle, unless I do a setup like a 250sx, and support it on the ends, but I think that is heavier?

The 20" bike for suspension parts, is what I was thinking of using. Could probably get a new one from wal-mart for about $100 or so. Use the forks, rear suspension, maybe chop the frame, and reweld, and use the sprockets.

Just need to figure out this axle thing. There has to be a simple way.

[riverrat]

I buy a hunk of 01 steel .750 or .875 and mount it in a Bridgeport cutting a .1875 or so keyway for every drive component. Then I'd broach my own key slot machine and weld up hubs for everything.

What is 01 steel? Is that heat treated?
Probably don't even need it, 3/4 steel rod is pretty strong, especially at the length I want to use it, maybe 24-28"

[RedRider_AK]

You could widen the bicycle swingarm (just bend the hell out of the chainstays and then rebend the dropouts even again when you're done) and maybe reinforce it with some steel strips. Then mount bearings in the chainstays and use a custom axle. That was it's supported at two points and will not bend as much. It all depends on what the thing is going to be used for. I remember I bought a "custom made" minibike with a 5 horse Tecumseh (that's actually why I bought it, the engine was never run). It was made of a 26 inch bike frame, hacked and and jimmy rigged. They even widened the stock front fork to accept an ATV sized tire, and did the same to the back. It looked TERRIBLE, but it worked, somewhat. I took the thing apart the second day I had it, it was just too scary to think about the front fork snapping in half while I was bombing down a trail or something. What sort of tires and wheels are you using for this project?

[super90]

A weedeater engine will never pull a solid mini trike like some described like with the 110 axle and forks. I used to have a 30cc 2 stroke engine out of a 'eater in a small 18'' bike. It was mounted between the frame and welded with some small brackets. It had a 6 tooth sprocket on the engine with a chain that drove a 44 tooth drive sprocket, which drove a 9 tooth on the otherside, that drove a 35 tooth. Top speed of around 20 mph. But I will say it had no balls at all! If you messed with gearing enough and somehow came up with some crazy sprocket system it might pull a metal trike, but weed eater engines just dont have enough power to pull more than a bicycle. If I were you I would look into pocketbike motors, Their meant for that stuff and will last alot longer.

[riverrat]

You could widen the bicycle swingarm (just bend the hell out of the chainstays and then rebend the dropouts even again when you're done) and maybe reinforce it with some steel strips. Then mount bearings in the chainstays and use a custom axle. That was it's supported at two points and will not bend as much. It all depends on what the thing is going to be used for. I remember I bought a "custom made" minibike with a 5 horse Tecumseh (that's actually why I bought it, the engine was never run). It was made of a 26 inch bike frame, hacked and and jimmy rigged. They even widened the stock front fork to accept an ATV sized tire, and did the same to the back. It looked TERRIBLE, but it worked, somewhat. I took the thing apart the second day I had it, it was just too scary to think about the front fork snapping in half while I was bombing down a trail or something. What sort of tires and wheels are you using for this project?

Not sure yet, but was thinking anything 4.5" Like some go-kart tires, with tread.

[riverrat]

A weedeater engine will never pull a solid mini trike like some described like with the 110 axle and forks. I used to have a 30cc 2 stroke engine out of a 'eater in a small 18'' bike. It was mounted between the frame and welded with some small brackets. It had a 6 tooth sprocket on the engine with a chain that drove a 44 tooth drive sprocket, which drove a 9 tooth on the otherside, that drove a 35 tooth. Top speed of around 20 mph. But I will say it had no balls at all! If you messed with gearing enough and somehow came up with some crazy sprocket system it might pull a metal trike, but weed eater engines just dont have enough power to pull more than a bicycle. If I were you I would look into pocketbike motors, Their meant for that stuff and will last alot longer.

I know, I know, but this is going to be a toy.

I fly R/C planes, and convert weedwackers to fly. When you run them on alcohol, and do some work to them, they can put out a solid 2.5hp

But I was concerned about gear ratio, since they spin about 9,000 rpm's

I am going to leave room, to put a larger engine in, if I think it is up to the task.

I am just in the information gathering stage, I am not sure if I would do this, or a rm80 conversion. I think whatever parts fall in my lap first. I just love talking about it, and learning from everyone.

[hondahaulic]

if the weedwacker isnt powerful enough, use a chain saw!!! pretty sure they all have a clutch and everything that would be needed. if its gonna be more of a toy for you to screw around on than anything, i'd try to used the sprocket system from a multi-speed bike. but if its gonna get used alot by younger ones, you might wanna keep it as simple as possible.

oh and by the way, what alll needs to be done to a weedwacker to convert it to alchohol? im curious lol