Two Wheel Tractor, Intermediate Technology

By Andy the stuff doer

This is one of those projects born out a few cans of beer.  Briefly I need to be able to tow a trailer in and out of the woods and to tow logs about.

I had thought of a salvaged four wheel drive car, but its more than I need and too big to get everywhere in the woods.  A small tractor would be nice but even second hand they aren’t cheap. I came across the two wheel tractor concept, basically a rotovator without the tines, I’ve been bidding on ebay for months but the prices or distance to collect have been silly.

So lateral thinking kicked in. Make my own. Two off road wheels powered by a bike engine. I’d got the bike, my old CB 100 N that I passed my test on. But not the wheels. Right, how can I make it Scrap heap Challenge style, scavenging from my own or friends personal stocks of bits. The wheels, I decided can be the bike wheels with low ground pressure, wooden treads 

So the plan, no drawings, no messing about, as quick as I can.  I’ve not clearly thought how I can drive it but it will have plenty of torque, using a half shaft to lower the gear ratio and wood treads fixed to bike wheel rims. It’s a shame I can’t think of an easy way of reversing it but hey-ho, as Dave pointed out ” you can push it”.

So here’s the donor bike –

CB100n bike to make two wheel tractor out of

My first bike, sat in various garages for years, I knew it would come in for something

Stripped down to what I need. Anyone need some vintage motorbike bits?

Stripped down CB100n motorbike

The bare essentials for the power unit

I checked the Haynes book of lies, I should only the need the power from the alternator, rectifier and coil to run the engine. If I think on maybe a switch would be good idea, Safety first and all that.

Next bit took some thinking about, connecting the wheels. Easy with a solid shaft but that would mean a set bearings I’ve not got spare.  So I made a shaft from tube and welded the wheel nuts in each end. That means I can use the existing wheel bearings and use the existing wheel bolt to fix them to a much modified no longer “Swing arm” and have the chain adjusters in place.

Motorbike wheels connected for two wheel drive tractor

Wheels joined in line, almost

Next is to attach a new drive sprocket. The original drive sprocket will be on one end of the half shaft to match the pitch of the engine sprocket.  The new sprocket comes from a CB550 wheel and I’ve got a engine sprocket to match for the other end of the half shaft.

The CB550 sprocket is modified with four nuts welded on to CB100 wheel

Sprocket and drive modification to motorbike wheel

Drive bodging sprocket to wheel - sprocket to drive shaft

To take the drive over to other wheel, I’ve got a piece of tube going over the connector tube. This locates on the drive sprocket with four bolts on bits of bar.

drive shaft to brake disc

Start of the drive shaft to brake disc connection

The other end of the drive shaft will connect to brake disc. Two bits of square section welded to shaft and two bits of angle welded to the disc. This will need a bit slop in it to account for the wobbly wheel connection.

That’s it so far, two evenings playing with welder and angle grinder.

Next part of build – PART  2 now UP

4 Responses to “Two Wheel Tractor, Intermediate Technology”

  1. The machines you refer to are commonly called ‘power tillers’ or ‘walking tractors’. Look up ‘power tiller’ on Google and you will find literally thousands of entries.
    World wide, over 500,000 two wheel tractors are manufactured, mainly in China or Thailand. They are purchased by small area farmers, principally in South Asia. A chinese 12HP unit, with attached rotavator, sells for around $US12-1300 ex works in China.

  2. Thanks for that info. I had seen a few on the web but had no idea how popular they are in the far east. If what I’m doing works, It will be interesting to see if converting a small motorbike in to a “walking tractor” will be a low tech cheap solution in other regions (hence the intermediate technology tag).

  3. I want to use motor bike engine for minor agricultural work, ploughing in sugarcane farm etc…. Appreciate if you could suggest something

  4. Hi Nitin, The most difficult part is gearing the output down to a slow speed. I used an additional chain and sprocket set giving an extra reduction of 3:1. if I had the parts available I would use more reduction giving slower speed and higher tourque. The wheels and axle then need to be able to transmit this tourque. Motorcycle wheels may not be strong enough especially if they have treads that have a good grip on the ground. Small car wheels on a solid axle may be better in this situation. I would love to how you develop this idea, please let us know how you get on.
    Good Luck

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