Scratch

jji7skyline · 2012-04-03 20:05:23

I'm planning on attaching a small 25cc engine to a bike (likely to be a bmx bike) and detaching the pedals. The engine will drive the wheels via a chain.

Has anyone ever done this before? I've seen one bike like this, and wanted to do it.

I'm planning on getting the engine off a string cutter (no, it doesn't cut string, google it).

fire219 · 2012-04-03 20:43:31

jji7skyline wrote:
I'm planning on attaching a small 25cc engine to a bike (likely to be a bmx bike) and detaching the pedals. The engine will drive the wheels via a chain.

Has anyone ever done this before? I've seen one bike like this, and wanted to do it.

I'm planning on getting the engine off a string cutter (no, it doesn't cut string, google it).

I assume "string cutter" is a weed eater. tongue

You probably need some heavy gearing for that engine to do much than stall out on a road that is even 1 degree slanted upward. Especially when 25cc is awfully small even for a weed eater, which usually have 41cc engines in my experience.

jji7skyline · 2012-04-03 21:47:27

The engine will be 2-stroke, so it may have low low rev torque, so I agree with you on the stalling thing. I'm thinking of getting the largest rear cog I can get and chaining it to a tiny front gear wheel tongue

I probably won't be able to do a clutch on it, but since the wheel will be directly connected to the engine, I may be able to start the engine by simply rolling the bike along the road a bit. What do you think?

cheddargirl · 2012-04-03 22:02:39

I haven't tried something like this (I don't even own a bike lol ), but I have seen bike motor kits on the internet. Maybe it's a bit worthwhile trying to download a few kit instructions to get a general sense on how to put it all together? smile

Laternenpfahl · 2012-04-03 22:04:55

do you have access to things like a welder and help?

jji7skyline · 2012-04-03 22:20:53

Laternenpfahl wrote:
do you have access to things like a welder and help?

I don't have a welder, I have a solder, and I don't really have much help tongue

I don't really want to use an electric motor to drive it, as I don't like charging batteries etc. etc.

I prefer internal combustion engines tongue

slayerrobe7 · 2012-04-03 22:29:13

someone i know did this and he had trouble you actually need a rather big engine i reccomend at least 50cc otherwise going places will be tough also if you can find a way for peddles to work as a back up that would be good

jji7skyline · 2012-04-03 22:50:29

slayerrobe7 wrote:
someone i know did this and he had trouble you actually need a rather big engine i reccomend at least 50cc otherwise going places will be tough also if you can find a way for peddles to work as a back up that would be good

Paddles as a backup would be super, but hard to do xP

I guess a larger engine would be better... know any good places to get them?

slayerrobe7 · 2012-04-03 22:55:14

my friend got a kit from Amazon.com but he only wanted the engine he "jerry rigged" the rest of it

jji7skyline · 2012-04-03 23:06:04

slayerrobe7 wrote:
my friend got a kit from Amazon.com but he only wanted the engine he "jerry rigged" the rest of it

jerry rigged?

and can you link to some kits?

slayerrobe7 · 2012-04-03 23:08:22

one seck

"jerry rigged" made a solution to fix or improve something even if it is not the intended way

Last edited by slayerrobe7 (2012-04-03 23:19:59)

slayerrobe7 · 2012-04-03 23:19:37

hmm i cant seem to find the one my friend used and i dont want to recomend one that wouldn't work however you might be able to get a lawn mower engine that would do the trick if you could find a way to mount it

jji7skyline · 2012-04-04 00:02:50

True, but I find that lawn mower engines don't rev very well... not as well as string cutter engines hmm

slayerrobe7 · 2012-04-04 00:10:48

hmm but i believe they get better rpm

jji7skyline · 2012-04-04 00:20:04

No, I don't think they go much over 4000 rpm hmm

slayerrobe7 · 2012-04-04 00:47:23

hmm what about a 50cc dirt bike engine tho that might be a bit dificult to obtain

jji7skyline · 2012-04-04 02:04:28

Might as well get a dirt bike if I'm gonna use a dirt bike engine tongue

fire219 · 2012-04-04 08:43:57

Yea, lawnmower engines have a fair bit more torque than a weed eater's (especially one from a ride on mower), but you have to max the throttle to get more than 3000RPM out of it. Not to mention that lawnmower engines are too big to fit on a bike frame, and sound like someone took a Harley bike engine and filled it with rocks. tongue

But you do need a bigger engine than 21cc. This looks to be about 41cc, and is working fine on friction drive, no gearing at all.

jji7skyline · 2012-04-04 19:32:02

fire219 wrote:
Yea, lawnmower engines have a fair bit more torque than a weed eater's (especially one from a ride on mower), but you have to max the throttle to get more than 3000RPM out of it. Not to mention that lawnmower engines are too big to fit on a bike frame, and sound like someone took a Harley bike engine and filled it with rocks.

But you do need a bigger engine than 21cc. This looks to be about 41cc, and is working fine on friction drive, no gearing at all.

Well you can see that the wheels are pretty small, and the friction drive wheel creates a very low gear.

This is actually a good idea! Thanks for showing me the video! smile

fire219 · 2012-04-04 20:14:23

jji7skyline wrote:
fire219 wrote:
Yea, lawnmower engines have a fair bit more torque than a weed eater's (especially one from a ride on mower), but you have to max the throttle to get more than 3000RPM out of it. Not to mention that lawnmower engines are too big to fit on a bike frame, and sound like someone took a Harley bike engine and filled it with rocks.

But you do need a bigger engine than 21cc. This looks to be about 41cc, and is working fine on friction drive, no gearing at all.
Well you can see that the wheels are pretty small, and the friction drive wheel creates a very low gear.

This is actually a good idea! Thanks for showing me the video!

An even bigger wheel would create an even lower gear, and would still would be faster.

And you're welcome. smile

jji7skyline · 2012-04-04 20:18:03

fire219 wrote:
jji7skyline wrote:
fire219 wrote:
Yea, lawnmower engines have a fair bit more torque than a weed eater's (especially one from a ride on mower), but you have to max the throttle to get more than 3000RPM out of it. Not to mention that lawnmower engines are too big to fit on a bike frame, and sound like someone took a Harley bike engine and filled it with rocks.

But you do need a bigger engine than 21cc. This looks to be about 41cc, and is working fine on friction drive, no gearing at all.
Well you can see that the wheels are pretty small, and the friction drive wheel creates a very low gear.

This is actually a good idea! Thanks for showing me the video!
An even bigger wheel would create an even lower gear, and would still would be faster.

And you're welcome.

You're right!

The problem would be though that the engine woud stall any time I stop or come close to stopping hmm

fire219 · 2012-04-04 20:46:01

jji7skyline wrote:
fire219 wrote:
jji7skyline wrote:

Well you can see that the wheels are pretty small, and the friction drive wheel creates a very low gear.

This is actually a good idea! Thanks for showing me the video!
An even bigger wheel would create an even lower gear, and would still would be faster.

And you're welcome.
You're right!

The problem would be though that the engine woud stall any time I stop or come close to stopping

You would need a clutch, or restart the engine everything you completely stop. hmm

lukanater · 2012-04-04 20:51:53

My friend did this with a wagon and oil he produced from green algae in his bathroom.

jji7skyline · 2012-04-04 21:02:38

fire219 wrote:
jji7skyline wrote:
fire219 wrote:

An even bigger wheel would create an even lower gear, and would still would be faster.

And you're welcome.
You're right!

The problem would be though that the engine woud stall any time I stop or come close to stopping
You would need a clutch, or restart the engine everything you completely stop.

Clutch would be buggy. I'll just have to restart the engine all the time tongue

fire219 · 2012-04-04 21:13:05

jji7skyline wrote:
fire219 wrote:
jji7skyline wrote:

You're right!

The problem would be though that the engine woud stall any time I stop or come close to stopping
You would need a clutch, or restart the engine everything you completely stop.
Clutch would be buggy. I'll just have to restart the engine all the time

The weed eater should have a clutch on it, use it. tongue

Scratch

archived forums

#1 2012-04-03 20:05:23

Engine-bike?

#2 2012-04-03 20:43:31

Re: Engine-bike?

jji7skyline wrote:

#3 2012-04-03 21:47:27

Re: Engine-bike?

#4 2012-04-03 22:02:39

Re: Engine-bike?

#5 2012-04-03 22:04:55

Re: Engine-bike?

#6 2012-04-03 22:20:53

Re: Engine-bike?

Laternenpfahl wrote:

#7 2012-04-03 22:29:13

Re: Engine-bike?

#8 2012-04-03 22:50:29

Re: Engine-bike?

slayerrobe7 wrote:

#9 2012-04-03 22:55:14

Re: Engine-bike?

#10 2012-04-03 23:06:04

Re: Engine-bike?

slayerrobe7 wrote:

#11 2012-04-03 23:08:22

Re: Engine-bike?

#12 2012-04-03 23:19:37

Re: Engine-bike?

#13 2012-04-04 00:02:50

Re: Engine-bike?

#14 2012-04-04 00:10:48

Re: Engine-bike?

#15 2012-04-04 00:20:04

Re: Engine-bike?

#16 2012-04-04 00:47:23

Re: Engine-bike?

#17 2012-04-04 02:04:28

Re: Engine-bike?

#18 2012-04-04 08:43:57

Re: Engine-bike?

#19 2012-04-04 19:32:02

Re: Engine-bike?

fire219 wrote:

#20 2012-04-04 20:14:23

Re: Engine-bike?

jji7skyline wrote:

fire219 wrote:

#21 2012-04-04 20:18:03

Re: Engine-bike?

fire219 wrote:

jji7skyline wrote:

fire219 wrote:

#22 2012-04-04 20:46:01

Re: Engine-bike?

jji7skyline wrote:

fire219 wrote:

jji7skyline wrote:

#23 2012-04-04 20:51:53

Re: Engine-bike?

#24 2012-04-04 21:02:38

Re: Engine-bike?

fire219 wrote:

jji7skyline wrote:

fire219 wrote:

#25 2012-04-04 21:13:05

Re: Engine-bike?

jji7skyline wrote:

fire219 wrote:

jji7skyline wrote:

Board footer