brock grenfell

Motor size: 125cc
Wheel size: 15inches
Frame type: Bought
Drive type: Chain Drive
Ratio: 4:1
Top Speed: kph

Originally it was a Yamaha Jazz moped with a 50cc motor but the motor had almost had it, struggling to do 20km/h. So I decided to put a more powerful engine on it, a 125cc Victa motor from a lawnmower I picked up for $10. I continued to use the gearbox from the original motor as it had an inbuilt automatic centrifugal clutch and 2 gears. As shown in the pictures I got the thing done and it was going great reaching upwards of 60km/h on the trial run. It was going so much faster than it was initially supposed to go, that the 60km/h Speedo was destroyed, the spring just snapped and the inside thread was stripped. After about 6 months in its present state it remained and I decided to take it out for a day after a couple of weeks of non use. I was doing burnouts at the local reserve when it all of a sudden lost power. It turned out the centrifugal clutch had all but worn away, and now going 10km/h I was quite annoyed.

It sat unfixed in the backyard after that until now. I have decided to make a stand up scooter like the ones on the site. I have drawn up a scaled drawing of the future scooter, I will use the front end from the original scooter and the rear wheel and engine. I may upgrade the engine if necessary. I have decided to make it the ultimate little offroad scooter with front suspension in the forks and a rear suspension which pivots the motor with the back wheel it should be able to handle any terrain. I figure it will have an 11 tooth centrifugal clutch with a 44 tooth axle sprocket and with these 15 inch wheels with nobbies it should flog. I have calculated that with a 1:4 gear ratio a 4HP Briggs and Stratton engine revving at 5000rpm will reach 90km/h without taking into account the loss of speed due to the weight of the scooter and the rider.

I hope to have the scooter finished for the December holidays 2003 I have now finished school (O YEAH!!!) and have a bit of spare time and cash available. Once finished I will post pictures of the finished product and construction process.

Kind Regards

Brock Grenfell

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