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Engine on bike

Posted: Thu Aug 02, 2007 5:30 pm
by MisterSteve124
Ok well I talked about doing it a while ago but this summer me and my friend are actually gonna try it. We're gonna put engines on our bikes. I was thinking about either mounting them under where u sit or above the reat tire with one of those racks. My friends dad is a welder so we can get him to help us reinforce some stuff. I was just gonna put a clutch on the engines then run the chain right to the gear on the bike and use the front brake handle as the throttle handle. So what do you guys think? Think it'll work, any suggestions, and what size engine do ya think I'd need? Also I had one more question since motor shafts are usually on the left side of mopeds, mini bikes etc. (from driver perspective) Would it make a difference putting the engine shaft on the right since thats where the gears for the bike are? Or would I have to switch the gears on the bike to the other side? Thanks for your help and lets hope it works.

Posted: Thu Aug 02, 2007 6:42 pm
by Modderxtrordanare
I've always wanted to do that, but on a wheelchair. :lol:
I actually plan to do it this coming year, as part of my senior prank...


Wait, are you planning on putting an electric engine on it or a gas one?

Posted: Thu Aug 02, 2007 6:45 pm
by schmanman
here is what you are looking for.

http://www.mopedarmy.com/photos/catagory/5/4563/

Image

have a roller to drive the rear wheel.


the motor mount obviously does not need to be that complex.


http://www.motoredbikes.com/

a whole FORUM on motorised bikes, most home built.


http://www.motoredbikes.com/

Posted: Thu Aug 02, 2007 7:25 pm
by ProfessorAmadeus
does a weed whacker have a horizontal shaft?

Posted: Thu Aug 02, 2007 7:36 pm
by Fnord
Holy crap! The professor's back!
Where were you?
I don't think a weed wacker would have enough power to be very usefull.

Schmanman: That setup would get a bit hot after a while!
Better get a banana seat if you plan on doing that :)

Edit at Modder: Wouldn't turning a weed wacker on it's side cause problems with the engine? Do most modern weedwackers use a fuel/oil mix or do they have an oil reservoir? I made the mistake of tipping a lawnmower the wrong way and the oil got into the air filter, which caused it to start smoking horribly and shut off.

Posted: Thu Aug 02, 2007 7:39 pm
by Modderxtrordanare
ProfessorAmadeus wrote:does a weed whacker have a horizontal shaft?
You could turn it sideways and it would be.


(Prof, the texas meet got postponed. Me, salt, and redneck moved it up to spring break if you can make it. It's up near salts place)

Posted: Thu Aug 02, 2007 8:00 pm
by MisterSteve124
schmanman I'd prefer not to use a spindle. It's just easier to run it straight to the gears and I'd get more powder plus it wouldn't ruin the tires but yeah that looks like how I would mount it and thanks for the link!

Posted: Thu Aug 02, 2007 8:06 pm
by Big-mac
go for a chainsaw motor.

Posted: Thu Aug 02, 2007 8:40 pm
by MisterSteve124
nah I'd want more power than that!

Posted: Thu Aug 02, 2007 9:18 pm
by pyrogeek
Weed eaters do have enough torque, if you set the gear ratio correctly.
Get a chainsaw or snow blower though and it should be plenty good.

Posted: Thu Aug 02, 2007 9:40 pm
by hi
ProfessorAmadeus wrote:does a weed whacker have a horizontal shaft?
yes, ive taken them apart before. they have about 4 HP.

Posted: Thu Aug 02, 2007 9:42 pm
by pyrogeek
I highly doubt you could get 4hp out of a weed eater without nitrous or nitromethane. The engine has a displacement of about 25-30cc. I have a weed eater engine rated at 3hp, and it is 101cc displacement. Both rev about the same RPMs.

Posted: Thu Aug 02, 2007 9:45 pm
by hi
sorry, i guess i should have said with about 15% nitro fuel. thats what they use with RC airplanes, which is where the extra power comes from.

normal gas/oil mix you get about 2.5 out of 32cc. some put out more than others.

Posted: Thu Aug 02, 2007 9:55 pm
by Specialist
well my best bet would be to find a running older z50 or xr50, take the engine out and throw it onto a bike. thats what im going to do to my schwinn stingray. its either a z50 engine or a pw or jr50 engine. im leaning towards the z50. that would be best. 3 speed automatic with neutral. you cant go wrong. for my stingray it will give it realism because i have to shift gears and z50, xr50 engines are reliable and fun.

Posted: Thu Aug 02, 2007 9:57 pm
by pyrogeek
Indeed. Nitro will give a lot of kick to an engine. But what is the other 15%, and could you get it more concentrated? :twisted: I have a snow blower engine on a scooter that could use a little more...power.
EDIT: sorry, forgot, that stuff can be distilled to concentrate it.

With the newer engines, yeah, that sounds about right.