Weed Eater Friction Drive Bicycle

[rawly old]

Actually the channel is recycled from an old friction kit rotated 180 now with engine
on the right. Most of the materials were scrounged up. The bike was $15 , a never
ridden 3 spd from a storage. After years of struggling with cables,adjustments,bent
derailleurs, and cross-chained sprockets, this bike is perfect for a motored bike. A
couple clicks is all ya ever need. 1st is a low as most road bikes; 3rd is as high as
most mtn. bikes. 2nd's right in the middle, elegant simplicity.
I take delight in giving new life to old junk.

P.S. Hope you've not drilled mount holes yet, that Ryobi may not fit, some have
an asymetrical hole pattern. The old ones I have seem to be immortal, but Im
told that is not always the case.

 

[landuse]

P.S. Hope you've not drilled mount holes yet, that Ryobi may not fit, some have
an asymetrical hole pattern. The old ones I have seem to be immortal, but Im
told that is not always the case.

The Ryobi doesn't have a clutch, so I will have to attach a peg onto it and have a "straight to wheel" friction drive.

I just got the engine, and it is brand new. It hasn't even run for 5 minutes. The guy I got it from had bought a larger one and didn't want this weedeater anymore

 

[rawly old]

If that's the case, the mix is probably 50 to 1, but use 40 to 1 breaking it in. ....
in fact, I use 40 to 1 all the time in spite of factory specs.

 

[landuse]

Well, as I said, I was given a brand new Ryobi 30cc engine last week. I have decided to make another friction drive out of this one, and maybe hold off on completing the one that I started this thread with.

I have already done some work to get this one off the ground. I will be drag starting the engine, as I couldn't find a way of putting my bike peg on the shaft without removing the pull start. I have decided to make a simple bracket, that will pivot on a U shaped bracket attached to the frame. I will weld 2 strips of metal to the frame so that I can bolt the engine on.

I am going to be using turnbuckles and springs to tension the motor onto the wheel. I still have to weld up the U bracket for the frame, and buy the correct springs. I am going to have a look at springs today. It might take me a few tries to get the correct ones.

Here are some pics of the setup I have so far.

 

[rawly old]

Here's something I did along the same lines. Originally, the control arm
didn't look so awkward,but I later lengthened it for a bike with a very
long handlebar stem.
The engine is mounted to a piece of 1/8" alu 'L' angle. It's just a lever.
Pull up and hook to the top tube to engage/drag start. unhook and the
spring lifts it off the tire. It simply mounts to a single bolt thru the
bracket with a wingnut and lock washer.
Oh.., you'll have to do something to rough up that peg; it's far too
smooth for a good grip.
The engine seen is my immortal Ryobi. I bought it a flea mkt. for $5.
The lady was honest enuf to say it wasn't working, but for $5 I
thot I could fix it. The recoil starter was shot.(who needs it) All
it needed was a fuel filter. It's gotta be 25 yrs. old; still runs like
a champ.

 

[landuse]

I have decided for this build not to use a control arm (or suicide clutch. It is going to be engaged permanently. As I stated above, I am going to use turnbuckles and springs to tension the setup onto the wheel. I think that I might in the future do a clutch lever like yours and add it to my setup.

I am definately going to cut some lines with my grinder into the peg. I just put it on the engine to see if it would fit. I had to grind off the little levers on the flywheel that engage the recoil to actually get the peg to fit flush with the flywheel. Seeing as I wasn't using the recoil anyway it wasn't a problem. I am still going to use the covers that came off the engine, but just cut the recoil section away, so that the peg stickes out. I just think it would look neater that way.

The more I think about it, the more I like the idea of the "clutch" that you have. I think I might do it now, while I am busy with the build.

I have done a very amateurish picture of my setup. I am going to use Strips of metal, welded to my frame I made as the attachments for my engine. I have indicated them in red. They are 4mm thick, and seem really strong as I can't really bend them by hand. Do you think they would work, or do you think they might bend? (They are the same as the green painted strips of metal in the second pic).

 

[5-7HEAVEN]

JMO, a gravity clutch would make engine application much more usable. Without it, you'll be pedal-starting at every stop, or even off-idle.

Stopping uphill and starting up again will be tricky, as well as stop-and-go riding.

JMO.....

 

[landuse]

JMO, a gravity clutch would make engine application much more usable. Without it, you'll be pedal-starting at every stop, or even off-idle.

Stopping uphill and starting up again will be tricky, as well as stop-and-go riding.

JMO.....

I see what you are saying. I will incorporate something like what rawly old had into my build, so that I can raise the motor at idle and on hills.

 

[rawly old]

Well I know it looks kinda clumsy in it's present form, but it works pretty well.
Trick is position the 'hold down hook' so that when lifted into place one gets
just the right amount of pressure against the tire. It looked better before I had
to lengthen the grip, but it's function gives one a choice at stops. I have but to
reach a few inches to disengage and thumb the kill switch should a full stop be
necessary or just pause at idle. To go I just start pedaling and the pop it onto
the hook and it's running again,(after flicking the kill back on).

The grip extension means my hand
scarcely leaves the handlebars. As for the throttle lever, it's fixed to stay where
it's set, and I seldom have reason to move it. Of course this is moot, now
that the belt drive is my prime mover, but for a whacker set up it was pretty good.

 

[landuse]

Thanks rawly old. I will post some more as my build progresses. I can unfortunately only work over the weekends, as that is the only time I can get free.