Around the same time I was racing the CR250, I was making go carts and mini bikes for the kids using Victa lawn mower engines for the power source. Making stuff is an obsession with me, always has been if I can make it, I won't buy it! Back then I didn't have the tool and machinery collection I do now, all I had was a bench grinder, vice, hand drill, AC welder and a few hand tools, amazing what you can do with simple tools.
Early 125 Victa engines had a full circle Crank, balanced without piston and conrod for some reason. This meant the motors wouldn't run without the large disk underneath which held the cutting blades. I did try running the motors without the disk but the vibration was simply to severe. Later 160cc engines were balanced correctly, but as I got all the bits to make the engines from the rubbish dump, the 160cc engines weren't available.
So what to do. Well, I pressed the pin out of the crank, took it apart and cut great V shaped chunks out of the fly wheels, reassembled them with piston and conrod and balanceed them on knife edge rollers I made up, cutting and grinding the flywheels until the crank was balanced. This worked well and I found I could run the motors without the large plate.
Next came the go cart frame. The first one I made was made from water pipe. The drive system was just two pulleys and a V belt, to start you simply pushed the cart and off it went. As I had no brakes for it, I fixed the throttle at relatively low revs and installed an ignition cut out' switch I made next to the steering wheel. This worked quite well, just push the cut out plate, the motor died and the cart stopped rather abruptly. The wife's kids had a ball on this contraption racing around the back yard.
One day I decided to take the cart and kids out to a bush area not far away. The little girl next door asked if she could come too, so I cleared it with her parents and we all went out to a place called 'The Drop Zone', large, gravelled and cleared area I thought would be great. Both of the wife's boys had a great time sliding around on the gravel surface, then the little girl asked if she could have a go. I thought, Ok, that shouldn't be a problem as there's only one control - the cut out switch. I explained to her how to steer it, just turn the steering wheel. Disconnected the V belt and pushed her around in the cart until she got the hang of the steering. Once she was confidant with that, I reinstalled the belt and explained when she wanted to stop, just push the pretty red plate and the cart will stop. Got her to push the pretty red plate kill switch a few times until she was confident with that, then pushed the cart and off she went.
She was having a ball, zooming around, squealing in delight. Then she started panicking, forgot all about the pretty red kill switch and started screaming 'I want to get off now, get me off, get me off'. So off I ran after the cart trying to grab the back rail so I could lift the rear wheels up and stop the cart. But every time I reached out to grab the rear rail, she'd turn around to look at me and swerve, moving the cart further away from my grasping hand. After what seemed an eternity I managed to grab the rail and lift the rear of cart, then reached over and pushed the killed switch. Needless to say, I wouldn't let her on the thing after that and I had to sit down for a while to get my breath back.
On another occasion I took the kids and cart around to a nearby park. One of the local kids wanted a go, so I explained everything, Sat him down in the cart, gave it a push and off he went. He turned the steering wheel a bit abruptly and slid of the cart, depositing himself on the grass. But, the cart kept going - driverless. The cart did a few laps by itself with me in hot pursuit, the kids all disappeared and eventually the cart turned down a small gully and sputtered to a stop in the creek at the bottom. After that, I welded rails along the side to stop the kids falling out
I think I made about four of these go carts, plus one mini bike. All had balanced 125cc Victa lawn mower engines, solid rubber tyres and V belt drives, the later models with accelerators and the kill switch was retained. The last one had a full house motor, ported, expansion chamber, shaved head and a Pope, needle, carb, with a small weed eater carb tacked on, Ackerman steering, Reynolds seamless tube, etc. Unfortunately, this little beasty scared the crap out of the kids and they refused to drive it.
Later on a workmate gave me a 100cc Yamaha bike, I pulled the motor, rebuilt it and made a go cart frame for it. This was for me to race around the gravel tracks at the rear of Tindal RAAF base. I made a couple of expansion chambers for it, gave it a port job and took it out the back of the base for a run. This thing was a ball, although I couldn't use fourth gear as the gearing was too tall. I couldn't get a rear sprocket of the size I wanted, so I had to make one, but as it turned out, it was too small.
I was curious as to how fast this thing was, so got the wife to pace me in the Hilux 4WD. I left her behind, still accelerating, she said she gave up at 80 KPH and I just left her. At a guess, I think it probably would have run to 100/110 KPH. Turning into corners at 80kph on a gravel track is a real buz. I raced around on this thing for a while until one of the exhausts came loose and melted the piston. Couldn't get parts for it, so it was broken down and dumped.
Early 125 Victa engines had a full circle Crank, balanced without piston and conrod for some reason. This meant the motors wouldn't run without the large disk underneath which held the cutting blades. I did try running the motors without the disk but the vibration was simply to severe. Later 160cc engines were balanced correctly, but as I got all the bits to make the engines from the rubbish dump, the 160cc engines weren't available.
So what to do. Well, I pressed the pin out of the crank, took it apart and cut great V shaped chunks out of the fly wheels, reassembled them with piston and conrod and balanceed them on knife edge rollers I made up, cutting and grinding the flywheels until the crank was balanced. This worked well and I found I could run the motors without the large plate.
Next came the go cart frame. The first one I made was made from water pipe. The drive system was just two pulleys and a V belt, to start you simply pushed the cart and off it went. As I had no brakes for it, I fixed the throttle at relatively low revs and installed an ignition cut out' switch I made next to the steering wheel. This worked quite well, just push the cut out plate, the motor died and the cart stopped rather abruptly. The wife's kids had a ball on this contraption racing around the back yard.
One day I decided to take the cart and kids out to a bush area not far away. The little girl next door asked if she could come too, so I cleared it with her parents and we all went out to a place called 'The Drop Zone', large, gravelled and cleared area I thought would be great. Both of the wife's boys had a great time sliding around on the gravel surface, then the little girl asked if she could have a go. I thought, Ok, that shouldn't be a problem as there's only one control - the cut out switch. I explained to her how to steer it, just turn the steering wheel. Disconnected the V belt and pushed her around in the cart until she got the hang of the steering. Once she was confidant with that, I reinstalled the belt and explained when she wanted to stop, just push the pretty red plate and the cart will stop. Got her to push the pretty red plate kill switch a few times until she was confident with that, then pushed the cart and off she went.
She was having a ball, zooming around, squealing in delight. Then she started panicking, forgot all about the pretty red kill switch and started screaming 'I want to get off now, get me off, get me off'. So off I ran after the cart trying to grab the back rail so I could lift the rear wheels up and stop the cart. But every time I reached out to grab the rear rail, she'd turn around to look at me and swerve, moving the cart further away from my grasping hand. After what seemed an eternity I managed to grab the rail and lift the rear of cart, then reached over and pushed the killed switch. Needless to say, I wouldn't let her on the thing after that and I had to sit down for a while to get my breath back.
On another occasion I took the kids and cart around to a nearby park. One of the local kids wanted a go, so I explained everything, Sat him down in the cart, gave it a push and off he went. He turned the steering wheel a bit abruptly and slid of the cart, depositing himself on the grass. But, the cart kept going - driverless. The cart did a few laps by itself with me in hot pursuit, the kids all disappeared and eventually the cart turned down a small gully and sputtered to a stop in the creek at the bottom. After that, I welded rails along the side to stop the kids falling out
I think I made about four of these go carts, plus one mini bike. All had balanced 125cc Victa lawn mower engines, solid rubber tyres and V belt drives, the later models with accelerators and the kill switch was retained. The last one had a full house motor, ported, expansion chamber, shaved head and a Pope, needle, carb, with a small weed eater carb tacked on, Ackerman steering, Reynolds seamless tube, etc. Unfortunately, this little beasty scared the crap out of the kids and they refused to drive it.
Later on a workmate gave me a 100cc Yamaha bike, I pulled the motor, rebuilt it and made a go cart frame for it. This was for me to race around the gravel tracks at the rear of Tindal RAAF base. I made a couple of expansion chambers for it, gave it a port job and took it out the back of the base for a run. This thing was a ball, although I couldn't use fourth gear as the gearing was too tall. I couldn't get a rear sprocket of the size I wanted, so I had to make one, but as it turned out, it was too small.
I was curious as to how fast this thing was, so got the wife to pace me in the Hilux 4WD. I left her behind, still accelerating, she said she gave up at 80 KPH and I just left her. At a guess, I think it probably would have run to 100/110 KPH. Turning into corners at 80kph on a gravel track is a real buz. I raced around on this thing for a while until one of the exhausts came loose and melted the piston. Couldn't get parts for it, so it was broken down and dumped.
