| nuns minibike |
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Motor size: 125cc Wheel size: 12inches Frame type: half bought, half made Drive type: Chain Drive Ratio: 7.2:1 Top Speed: 55kph To start off with i bought myself a scooter. I got a "Bully Brawler 12" scooter from www.bicyclestore.com.au for AUD$100. This ended up being the most expensive thing on my scooter/minibike. Originally i was gunna use a Honda GX31 replica engine but before i got around to mounting it, i found a 125cc tecumseh engine on hard rubbish collection day, so i used that. It simply needed some carb work and then it ran well. To complete the frame i cut off the top half of a crappy old racing bike which i also got on rubbish collection day (oh what a glorious day!), then welded it to the scooter frame. I'd decided to make the scooter a chain driven bike as that seemed to be much more reliable and efficient. Unfortuntely i could not find a wheel which i could drill through, the rim, which i was intending on drilling was some kind of high grade stainless steel which is virtually impossible to drill without a press, I didnt even make a mark on it. Because i couldnt drill through the rim, i couldnt attach the sprocket to the wheel, i could have welded it but i tried that once before and the spokes just snapped under the heat, so it probably wouldnt have been strong enough. I finally found a wheel where the rim was simply made of mild steel which was easy enough to drill, so i put the sprocket on that. The throttle took severaly hours to set up due to the fact that all the springs were worn and weak so the throttle system had to be modified. when i finall got around to having a finished bike, with the chain on, and with everything working i decided to ride it around the back yard, and it went well! So i took it out onto the street and started riding it around a little, it had no trouble climbing hill, had great acceleration and a good top speed, this was due to the high torque that the motor provided. as it had plenty of power, i put some bike pegs on the rear wheel and told my brother to jump on. Unfortunately the mild steel rim which i bolted the sprocket onto was not strong enough to support both of us, so the rim snapped in half and the wheel practically fell apart. So i once again had the problem of needing a new rear wheel and some way to mount a sprocket. After a short time i simply decided to buy a tami dolphin II rear wheel and just bolt a #35 sprocket onto the sprocket that was already there. This worked very well and solved all my rear wheel problems. I had to get a custom axle machined for it as tami didnt sell one, but that only cost $20. Then when everything was completed i went to put the wheel in the forks and... the wheel was too wide to fit in the forks. DAMNIT. So then i had to make custom rear forks, which also involved cutting off half the bike frame that was welded onto the scooter. The custom forks and seat supports were made of 1" mild steel square tubing, its easy to weld, easy to cut, easy to work with, its good stuff ! So then i drilled out an axle hole put the rear wheel on and i was almost finished. Unfortunately the starter had also broken so i had to get a new one, the local mower shop didnt have one, so i went online and thought that i'd found one, i contacted the shop, Which was in the US (im in australia) and they said that the starter would work for my engine, so i bought one. It was one of those deals where they couldnt tell you the shipping charges so they just got your credit card details and charged it when they found out the shipping costs, i was slightly dubious of this because i didnt know how much i'd end up paying for shipping, AND WITH GOOD CAUSE!!!! they charged me AUD$100 shipping, god damn it! and then the piece of crap turned out to be the wrong starter so that was alot of money down the drain. then i discovered that i could use a drill with a socket to start the engine, so i did that, unfortunately this means that i can only start the scooter when im at home as my cordless drill wasnt powerful enough to start it. In order to put the chain on i had to go and buy a chain breaker, so i went down to a shop that sells them and the bastard there tried to charge me $130 for one, so i told him where he could put his chain breaker. Instead of using a chain breaker i simply grinded off the end of the chain pins and removed links. So then i chucked on the chain, and went for a spin. Unfortunately the sprocket on the rear wheel was a bit big so that the chain rubbed on the frame on the bottom. So i had to get a chain tensioner, but i couldnt be bother so i simply sticky taped a socket, with a whole lot of grease on it so the chain would run easily. I thought that the sticky tape would come off after about 10 minutes but the chain just wore it down in one spot and there was still plenty of tape on either side of the chain, so the socket held fast the the sticky tape on either side of the chain, held it in place. So everything worked out well. The rear tire has no tread left because i originally used it for a spindle scooter, so it skids heaps, and there is also a small punture in the tube so about every 30 minutes of riding you've got to pump up the tire again. Then when i was riding, the front tire just burst so i skidded to a stop, unhurt, and had to push it home. I got a new tube for the front wheel but couldnt be bothered getting one for the rear wheel yet. So for the new front wheel tube i got some "thorn proof" tube which is at least three times as thick as a normal tube, and heaps stronger. so now it works almost perfectly, ive just gotta get a real chain tensioner, and a new rear tube and rear tire. The acceleration is great, the top speed would be approximately 55kph and it gets to that speed in under 4 seconds. Its great fun. I go through the dirt paths in my local park and occasionally theres some old people walking through the paths, you should see the dirty looks they give me. There's heaps of thick sand on those paths though, and ive stacked a couple of time, never seriously though.
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