New project idea

It has been quite cold so I haven’t been riding my latest full suspension rig a whole lot, but I am very satisfied with it and I am continuing improvements and refinement.

I have a simple but excellent 12V lighting system, with bright lights front and rear. Yesterday I completed my brake light, rigging a bright red led to a simple 12V battery pack (4 AA batteries) to a simple switch attached to my rear brake lever. I soldered a metal spring and attached it to the throttle body with a small zip tie. I soldered a small metal washer and attached it to the brake handle. Another zip tie leads the washer to the spring when I squeeze. Simple and effective.

My financial situation is expected to be much better next year and my thinking is to buy a small motorcycle. But I have one more motorized bicycle idea:

I have a 140cc 4 stroke, taken from a lawnmower. I intend to convert it for horizontal use, welding on a oil slapped and closing and opening some holes. Should be very reliable. Would have to grind the drive shaft down from 7/8” to 3/4” for a chain driving centrifugal clutch.

I just snagged a motorcycle triple tree stem for a few bucks! I have a couple of nice springs that will fit the big tubes needed for the project so I am foreseeing a kind of plunger tube within a tube. I can make that work by chopping a headtube off a derelict steel bike and welding it to a cafe racer frame of my own design.

Researching pieces, I see that motorcycle fork tubes are very expensive.

I’m thinking that I can rig all this up, add all lights and mirrors and get a motorcycle tag. Has anyone done this?

 

[Will'smotobikes19]

Does that motor run good in the horizontal position? have you bench tested it? what all did you do to it. Just got an old weedeater 22" mower running and trying to fix a craftsman 6.75hp.

 

[Frankenstein]

Unistrut is strong! I used it on the bike I ride daily and it is unimpeachable. Stronger than any bicycle tube and welds really good. I prefer channel much better than tubes.

It's some tough stuff, absolutely stronger than even the old, great quality stuff that bikes used to be cut from. You could knock a man out with that, bicycle tubing (especially today's tubing) would crumble under some people's heads, but not unistrut.

It's a smart move, many people don't even understand how much raw torque is pushed through these frames which is ultimately what causes cracks and rips a frame apart. Think of just the gyroscopic forces up against the frame every time the wheel's position in space is changed, at high speeds (for a bike) that spinning mass resists being moved and starts applying that infamous 'equal amount of force' back into the frame, which flexes and slowly tears it apart.

Anyone who's had the time to playfully spin a wheel outside the bike and held onto the axle would have noticed by now the way it resists being turned, including even forcing itself into a off vertical position (tilting itself sideways) position in order to hold onto the gyroscopic spin with the least loss in the system. But anyway that event is resisted in the solid frame of a bike so that energy has to be dissipated somewhere, that's the stuff that helps kill a bike, vibrations are bad enough, but vibrating AND tensioning steel is a good way to rip it apart really quick.

So there you go, I can't prove it mathematically without too much effort that that strut is stronger stuff than bicycle tube, but I know that 60 feet of it in a bundle is a bit of an annoyance to carry, I'd think that the bicycle tube at a third of the weight wouldn't be so bad to move around, and in the back of my mind I'd be thinking of how much better commercial shelf tubing would be to make a bike with than the flimsy (and almost not even good enough for a bed frame for a toddler) bike tubing they are using now.

It's good stuff I'd use it if I had it on hand, I think another friend of mine used something fairly similar to fashion a few 212s into a few frames that normally don't hold those types of motors .

 

[Timbone]

Does that motor run good in the horizontal position? have you bench tested it? what all did you do to it. Just got an old weedeater 22" mower running and trying to fix a craftsman 6.75hp.

I ran the motor for all of 3 seconds! I attached it to the frame - forkless - and got it going with some starter fluid.

There are numerous videos on YouTube that can help. You must open the crankcase and attach a oil flinger to the con rod that will ensure lubrication. Also you need to
Fill in some holes with JBWeld and file some others so that oil goes where you need it. You also need to figure out a way to get oil into the crankcase once you’ve added your RTV gasket and lock it down.

I had to ground out a little piece of aluminum inside the crankcase to make room for the oil flinger. It can’t touch anything.

Of course the carb will need to rotate and you’ll need some kind of breather box for the crankcase vent.

 

[Timbone]

Did a mock up of the rear end so I can see how everything will fit up. Had to change my design to hold the monoshock but I got the seat height perfect.

 

[Will'smotobikes19]

Looks like a cafe racer already not bad. You did say you wanted to plate the bike? I know the custom motorcycle builders can get a vin made I'm pretty sure atleast. It would be cool to see what exhaust you come up with. Maybe you could even use an old one off a vintage honda or something.

 

[Timbone]

Man, I have not even thought about an exhaust. I have a 37” expansion chamber that I welded up last Summer - maybe I’ll do that!

I can only use new parts if I hope to get it titled under KY rules.

My handlebars and throttle assembly will arrive this week, so I’ll be able to play with the engine soon. As for today, I fabricated by disk brake caliper mount and I will weld that to my front fork tomorrow night. That’s how I do this, setting goals for each day or couple of days.

My big challenge will be my gas tank. I am going to try to weld up a part of a metal air tank to some flat metal and hope I can weld it pinhole freewith flux core. That is a project for next weekend.

Hopefully, I will have enough extra $$$ to buy all the extra things I need for next week: tubes, tires, spacers, washers, 415 chain, mirrors, etc. Electric system will have to wait a few weeks.

Thinking ahead to electrical, I am going to procure all my pieces and set up a kind of model, grounding my battery to a metal piece representing my frame and checking the wiring before doing it on a bigger scale.

Thanks for your comments!

 

[Frankenstein]

Looks like a cafe racer already not bad. You did say you wanted to plate the bike? I know the custom motorcycle builders can get a vin made I'm pretty sure atleast. It would be cool to see what exhaust you come up with. Maybe you could even use an old one off a vintage honda or something.

I've explored this idea quite a bit, found a couple custom bike makers here in PA and one in New Jersey who could be willing to work with me to get an official Vin AND title made out for my bike, even better they can get it made out for a moped, only catch is I am obligated to use a 49cc or smaller sized motor (though I think much like a big bore kit that can be added to any vespa or puch, my requirement is only need to be met during 'production' so after the fact I can probably get away with an upgrade.)

If I wanted a motorcycle Vin and title then I could use something significantly larger, but that comes with the cost of removing the pedals since again all manufacturers seem to be iffy about putting a motorcycle engine in anything that could be construed as a moped or bicycle, if that makes sense.

 

[Will'smotobikes19]

My mini chopper has a 49cc on it but the carb diaphragm s**t the bed it's stiff as a brick. I hate those carbs there's no real reason for that type to be on the bike since the tank is above the carb. I heard if the bike doesn't have a vin from factory even if it has all the lights and horn you still can't register it. I kinda like the idea of using a vertical shaft mower engine but something tells me they don't last long without the gov. with stock parts. Most of those mowers just have aluminum bore with no sleeve. The camshafts are usually entirely plastic even the lobes. If you could only increase the rpm from 3600 to maybe 4300 or 4500 instead of 5500 rpm maybe that would be better possibly a throttle stop would limit it?I have 3 push mowers now one of them runs and the other 2 I have to fix.

 

[Frankenstein]

My mini chopper has a 49cc on it but the carb diaphragm sh*t the bed it's stiff as a brick. I hate those carbs there's no real reason for that type to be on the bike since the tank is above the carb. I heard if the bike doesn't have a vin from factory even if it has all the lights and horn you still can't register it. I kinda like the idea of using a vertical shaft mower engine but something tells me they don't last long without the gov. with stock parts. Most of those mowers just have aluminum bore with no sleeve. The camshafts are usually entirely plastic even the lobes. If you could only increase the rpm from 3600 to maybe 4300 or 4500 instead of 5500 rpm maybe that would be better possibly a throttle stop would limit it?I have 3 push mowers now one of them runs and the other 2 I have to fix.

Well of course you can't register it, but the dmv doesn't know a darn difference between something tig welded in a factory or arc welded in a backyard by looking at a title or manufacturer's certificate of origin. They really don't care either, they have police officers on the ground to pick up on any and all inconsistencies that may exist.

As far as it becoming a problem it's virtually impossible for them to do anything, if you have a legitimate Vin from a legitimate source and have all your registration and insurance sorted then you're simply legal, even if they don't want to believe it's true they can't go out and say it's not true. Maybe if you were stupid and pulled a vin from a vespa or other recognizable brand and used that you'd be toast, but if you're registered as a custom cycle of some type from a source that makes custom cycles then what's to argue, it's a custom cycle!

As long as somebody has made it totally legit then you're in the clear, otherwise you're better off not registering or anything because then at least you can't get hung for fraud on the federal level, just get tickets for a non-registered vehicle (and maybe impoundment. Still cheaper than a felony.)

 

[Musico336]

I check this post everyday