125cc bicycle

H

hoskins_motor_projects

New Member
hey just finished up the last welds on my motorized bicycle project. its 125cc semi auto 4 speed. welded on a old raligh road bike. i extended the frame.. 250 shwinn shocks. carben fiber front rim. also have back not onstalled yet. will need to weld some chain tentioners.


do u think i will be riping up my spokes cause of the tork? and suddgestions would be awesome. im new to this site and this is my first real post

the picture is in the link . kijij

http://toronto.kijiji.ca/c-cars-veh...rs-choppers-motorized-bike-W0QQAdIdZ528956109
 
That looks frightening. normally i'd put a smileyface after a statement like that, but this time i'm not joking.

You might wanna weld some gussets everywhere you can on that frame. hanging that much weight up so high is probably gonna rip apart that frame.

And yeah, you'll probably destroy your back wheel. amongst other things.

Hopefully the whole bike doesn't fold in half the first time it shifts.

Sorry, just being honest...
 
You have some interesting ideas... Make sure you have someone making a video if ya take it for a full power rip. Please feel welcome here and stick around. Lots of helpful friendly people on this forum. But this build makes me want to go hide... Crazy fun; but scarry.
 
grinding down welds today and redoing some welds. used steel beams. for the motor mounts. also adding chain tentioner. will post a video on youtube now for closer look..
 
I've seen more than a few "hair raising" motorized bicycle builds and this is one of them. Please understand that nearly all 50 - 100cc motorcycles use frames that are 2, 3, and 4 times (or more) stronger than what you normally see in a bicycle frame, modified or not (many of these motorcycle frames are full double cradle designs that also use much heavier walled tubing and gussets).

I'll also mention that doing 45 - 50 mph on the average bicycle, let alone a heavily modified/motorized version, can be pretty "unsettling" (unless you're running very high quality and/or DOT approved tires and rims coupled with a good suspension system). And yes, a lot of high-performance motorized bicycle rider/builders push well beyond 50mph, but I'd bet that most of them had quite a bit of high-speed motorized bicycle and/or motorcycle riding experience before they began to approach such speeds.

Now lets talk about road conditions while riding your motorized bicycle at the speeds your machine might very well be capable of; the fact is that hitting a moderate pothole at 45 mph (even while riding on a good suspension and DOT rims and tires) could easily put you on the ground. Experienced riders (which you could very well be) are usually pretty picky about using smooth roads and/or roads that they know well while riding at such speeds.

Then there's the supremely important question of braking such a machine...

Having said all that; I do admire the enthusiasm you have for motorized bicycles.
 
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Welcome to the forum. I hope you don't take all the criticism wrong but there are some very experienced builders and riders here and we aren't always diplomatic about our opinions.

Nevertheless we are concerned first for your safety and second for the future of this hobby. At the speeds that your bike will be capable of a mechanical or structural failure could be extremely serious, or worse. Not only could you incur life threatening injuries but any investigation into the cause of the accident will reflect badly on the hobby/sport of motorized bicycles.

Bicycles being the keyword here. They aren't designed or built to have even the little engines we normally install on them but what you are building is for all intents, a motorcycle. As was said above, it still has bicycle wheels, frame (questionably modified) and bicycle brakes and bearings.

Some builders here have installed even bigger engines that your 125 but the upgrades have been extensive. Frames, wheels, bearings, spokes and most importantly, brakes.

If we can suggest one thing it would be for you to be very very careful riding that machine. For your sake and that of our hobby.

Tom
 
Holy Deathtrap Batman! To the welding shop!
I'm nicknamed "Maniac" and I wouldn't ride it without some serious reinforcing,,,
 
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