Petrol power scooter

[coolvxss]

Hey guys, i got a spare 25cc whipper sniper and want to put the motor on a bike or scooter. Which one would be easiest and does anyone have a plan or something on how to make one? I have never pulled apart a whipper snipper before. cheers

[matty88]

Easiest way is to weld a sprocket onto the shaft from the motor, then run a chain/belt to the wheel, we did this at high school, it was great fun!

[coolvxss]

How did you clutch it. like when your not moving how did you stop it from stalling?

[matty88]

We had a lever that lifted the whole engine up off the wheel from memory? The one we made didn't use the sprocket from what I can remember, it had a small wheel on the engine and it just rested against the tyre (for a scooter this is)

[coolvxss]

Thats what i was thinking, just have a small wheel rub on the tire and make it go. might make it easier. did the scooter go alright?

[Wombat]

Coincidentally, I'm about to do the very same thing.
We too have an old whipper snipper motor and an old 1970's scooter. The easiest way is indeed to fit a sprocket to the engine, but it takes a little more ingenuity with the metalwork...leave the clutch unit on the engine, and you have to make a mount for the engine, with a bearing the other side facing the "snout" where the drive comes out. A shaft (cut from the original long inner drive shaft with the square end on it) has a small sprocket welded to it and trued up. One end of this goes into the clutch snout, and the other then has the bearing support bolted on from the other side.
As I said, this takes a little more frigging around, but you will end up with a very efficient little unit.
One point about the sprockets...if you are using a standard sized scooter wheel on the back, go for the biggest sprocket you can get to fit, and on the engine side, the smallest that will go on. This will multiply the available power and let it drive along with a fair sized adult on it. Use standard pushbike chain...we aren't talking massive horsepower here.
I only have the design in my head, but I have seen a couple of homemade ones over the years, and it works very well.

...and then if you are game, you can start experimenting with a fabricated sports exhaust and chamber, and a small air pod for the carby...shave the head, or base of the barrel if it doesn't have a seperate head (watching carefully for piston-spark plug clearance) and have some fun!!!

[matty88]

Me and my mate made an outboard from a whipper engine.... stuck it onto our rubber dinghy.... food for thought....

[coolvxss]

Hey guys. couple weeks ago i got the motor on my bike and it goes heaps good. Just used some metal plates and u-bolts to hold them to bike frame. I put a digital speedo on it and its max speed is 46 on flat ground which may not sound like a lot, but when your on a little 20" push bike it feels like your going 100. The odo meter says ive done little over 90km on it and its still going strong.

Just wanted to know, does anyone know the legal side of riding these things? I have been just riding it on some dirt trails and dirt tracks and bike paths, but dont want to go near many roads because i thought they might be illegal? I searched google but all they say is you cant go over 200watts, which doesnt mean much to a petrol engine. Its only 25cc.

[sganro]

Me and my mates did this with a blower motor (by blower i mean a thing for spraying insecticide/liquid fertilizer on trees or what not. Motor was mounted on a back pack with the tank of juice and basically ran as a pump to spray the juice through the nozzle). Anyways, we welded up our own scooter frame out of 2 old BMX frames. It was the sort of scooter like those little ones that all the little kids have these days. Platform to stand on with the front end of one of the bikes for steering. Turned the brake lever and cable into a throttle lever so it was just a squeeze throttle on the handle bars - very responsive!

Mounted the motor so that the drive shaft rubbed up against the back wheel. Pump up the back wheel heaps and away we went.
Now the motor was 50cc and this thing had rediculous torque for a little 2 stroke. Just trying to pull start it, you had to give it a huge yank or it would just lock up on compression.

We didnt have a clutch on ours. Just stand on it with one foot, kick with the other and pump the throttle as ya go. She'd fire up and then the fun would begin. We never actually clocked its speed but it would have gotten close to 70km/hr as a mate had a go cart that went 80km/hr and it nearly kept up with that. Got pretty scary when the speed wobbles kicked in at top speed lol.

We had so much fun on that thing and it kept us out of trouble for ages. We were only about 15 when we did that (so about 7 years ago) but still remember the old beast.

[VTPREDATOR]

how hard would this be to do with a lawnmower engine? ive got a new 4hp mower engine that i reckon would go nuts on a pushy.

[ProphetVX]

Me and my mate made an outboard from a whipper engine.... stuck it onto our rubber dinghy.... food for thought....

Paddling with your hands probably would have been faster

[coolvxss]

Yeah i was gonna use a lawn mower engine but they were too chunky for the bike so i stuck with a little 25cc. it still hawls ass. I love taking it around the dirt trails. Does anyone know the legal side of things for these?

[coolvxss]

i found this MOTORISED BICYCLE LAWS IN AUSTRALIA but it says nothing about petrol powered bikes. only says cant ride anything over 200watts.

[matty88]

how hard would this be to do with a lawnmower engine? ive got a new 4hp mower engine that i reckon would go nuts on a pushy.

One way to do this is to make a trailer for the engine (try mounting it on the bike is nuts) and have the engine run the wheels, throttle would obviously need to go to the handlebars. I'll do it one day with a freshly rebuilt 5hp engine I have

[KingDiamond]

how hard would this be to do with a lawnmower engine? ive got a new 4hp mower engine that i reckon would go nuts on a pushy.

Would need a bit of tweaking... They only rev slowly as a mower, and can do well over that if needed.

[ProphetVX]

i found this MOTORISED BICYCLE LAWS IN AUSTRALIA but it says nothing about petrol powered bikes. only says cant ride anything over 200watts.

Watts still has the same meaning for power in petrol terms.

Our cars use kw to measure power. There are 1000w in a kw.
1hp = 745.6w

So basically nothing is really legal.

[coolvxss]

Watts still has the same meaning for power in petrol terms.

Our cars use kw to measure power. There are 1000w in a kw.
1hp = 745.6w

So basically nothing is really legal.

So if the police get me cruzin round. how can they prove that my bike is over that. 200w isnt much at all then. I dont think i will worry about it. Unless the cops can run at over 40kmh or have a motor bike, there not gona catch me.