Weed Eater Friction Drive Bicycle

[rawly old]

Good luck and don't get discouraged. Half the the fun of this hobby is tinkering
and figuring ways to make things work.

 

[landuse]

OK, so I pretty much finished my bike this weekend. There are one or two things that still need to be done like fixing the kill switch to the frame, and neatening up some of the cables. I also have to do the scissor clutch, as I didn't have time to do it this weekend.

I first welded the metal strips I am using as a motor mount to my frame. It was a bit of a pain to get everything lined up, but I got it done in the end. I also fixed my frame to the bike, so everything was lined up. I then mounted the engine, cut some grooves in the foot peg, and added the springs and turnbuckles.

The springs worked better than I had hoped. I had bought much longer springs originally thinking that the whole frame would sit higher than what it does, but fortunately I had the shorter ones lying around. I just drilled a hole on either side for the spring to hook onto.

On Saturday I went to our local bicycle shop, and bought some more brake levers for my throttle and clutch. I mounted then on the handle bars opposite to what they should be, so that I could operate them with my thumbs. I had also bought some cheap brake kits, so I had a few pieces that I could use to set the accelerator up. I took a pic of where I connected the two cables. I hope it works out OK.

I lengthened the kill switch, so it reaches the handles now. I must just buy some more zip ties to neaten it all up. By this time it had started raining, and I wasn't able to take it on a test run, but this evening when I get home (if it isn't raining) I am going to give it a run.

I will let you know how it turns out

 

[rawly old]

That looks like it'll work just fine, very clean looking build. The turnbuckle
is ideal for making a precise pressure adjustment. I like it. Gas 'er up and go.

 

[landuse]

I was all exited when I got home last night to try my bike out. I hopped on, started pedaling with the choke on till it wanted to start and then took the choke off. It started fine, but I just had no torque at all. It was really dissapointing. When I turned round at the end of the street to come back home I had a bit of a downhill, so that went fine.

When I got off the bike and had a look at the motor, I saw that the roller had come loose, and could rotate on the motor shaft a bit. This was probably causing the terrible torque. I think the roller is also too big for my motor. It is a 1 1/2" foot peg. I think I might try something with a smaller diameter.

I also smelled something like burning rubber, but it wasn't the tyre at all, it was the engine. I also saw a wisp of smoke come from the engine. Do you think that the loose roller could have overheated something on the engine to make that smell. The tyre still looked good.

Do you think there is enough air flow round the engine with the engine covers like they are. I cut the front off as you can see.

It was a dissapointing first run, but I will get her right soon.

 

[rawly old]

As the engine is new, I'd expect some smoke on break-in, but the rubber smell is
definitely the tire. Hopefully, some threadlock or epoxy will lock down the roller.
Guess I shoulda said something, but I didn't want to discourage you. The roller is too big, but it's the springs flexing. You have to have solid contact. Go with a 7/8" or 1'' roller
That's why I went with a lever to latch it down and a spring to lift it off. Hey,
life is trial and error; it's the way we learn. Sorry 'bout that, but I knew you'd
have to try it for yourself.
What mixture are you using on the gas. If it's 40 to 1 as it should be for break in
you can expect more smoke than normal. As long as it's not a lot of thick smoke
you should be okay. You'll need to change the fuel filter after the first gallon;
by then it should be broken in.
Does the roller fit snugly to the base of the shaft. If it does, it reinforces the
shaft. If it it not tight against the flywheel, there may be too much stress on the
bearing. Even if it is, you can run a long time, but eventually this will be the probable
point of failure.

 

[rawly old]

Landuse,
Look, I'm gonna level with ya; I'm not saying you can't build a direct drive
weed whacker setup that works well, because you can. Thing is, I've been
through the whole gamut of weedys & kits. Friction is okay if it's not wet or
you don't ride a lotta dirt. You can get a lot power out of an in-frame chain
kit if you can afford a reliable engine, but and truly good setup ain't cheap.
Even the best requires a good deal of maintenance. There is a pretty
good belt drive kit out there,(G.E.B.E), but it ain't cheap either.
As far as engines go, I think a reliable 4 stroke is the way to go, Honda or
subaru. For a 2 stroke, I'd choose a tanaka 40cc. My choice of setup is
a belt drive, and I'm running a 4 stroke honda gx35cc. I'd run a 50, but
in my state, that might have legal problems and its difficult getting a clutch
for a gx50, though not impossible. The belt drive is relatively hassle free,
and I can run on any surface. ....That's my take on motorizing a bike. In
the long run, it's probably easier just to buy a moped, but where's the
challenge in that?

 

[landuse]

As the engine is new, I'd expect some smoke on break-in, but the rubber smell is
definitely the tire. Hopefully, some threadlock or epoxy will lock down the roller.
Guess I shoulda said something, but I didn't want to discourage you. The roller is too big, but it's the springs flexing. You have to have solid contact. Go with a 7/8" or 1'' roller
That's why I went with a lever to latch it down and a spring to lift it off. Hey,
life is trial and error; it's the way we learn. Sorry 'bout that, but I knew you'd
have to try it for yourself.
What mixture are you using on the gas. If it's 40 to 1 as it should be for break in
you can expect more smoke than normal. As long as it's not a lot of thick smoke
you should be okay. You'll need to change the fuel filter after the first gallon;
by then it should be broken in.
Does the roller fit snugly to the base of the shaft. If it does, it reinforces the
shaft. If it it not tight against the flywheel, there may be too much stress on the
bearing. Even if it is, you can run a long time, but eventually this will be the probable
point of failure.

Thanks rawly old. Yup, it was dissapointing, but I figured things wouldn't work out perfect first time round. I am going to get a smaller roller for sure. The roller does fit snug against the flywheel, so there shouldn't be any abnormal stresses there.

The fuel mixture I am using is 30 to one. It is what the manual recommended for break in. Should I use 40 to one?

Landuse,
Look, I'm gonna level with ya; I'm not saying you can't build a direct drive
weed whacker setup that works well, because you can. Thing is, I've been
through the whole gamut of weedys & kits. Friction is okay if it's not wet or
you don't ride a lotta dirt. You can get a lot power out of an in-frame chain
kit if you can afford a reliable engine, but and truly good setup ain't cheap.
Even the best requires a good deal of maintenance. There is a pretty
good belt drive kit out there,(G.E.B.E), but it ain't cheap either.
As far as engines go, I think a reliable 4 stroke is the way to go, Honda or
subaru. For a 2 stroke, I'd choose a tanaka 40cc. My choice of setup is
a belt drive, and I'm running a 4 stroke honda gx35cc. I'd run a 50, but
in my state, that might have legal problems and its difficult getting a clutch
for a gx50, though not impossible. The belt drive is relatively hassle free,
and I can run on any surface. ....That's my take on motorizing a bike. In
the long run, it's probably easier just to buy a moped, but where's the
challenge in that?

I am not too concerned if I don't get this bike going well. I am one of these people who like tinkering with things and trying out all new ideas. I am not doing the friction buke for any means of dedicated transport, rather it is just for the fun of doing something, and learning as I go. A year ago I was clueless about anything mechanical, and now I am pretty good at welding, engines etc. It has become sort of a hobby for me. If the bike doesn't work out, I will move onto the next project and give that A try. I will see if I can get this working well first.

I have been toying with the idea of getting a HT engine kit for the bike, but it is an expense I am not too sure I want to incur at the moment.

Thanks for all your help though. I am going to try and get this friction drive to work though, so any future help will be appreciated. And if you see me going wrong, you must stop me.

 

[rawly old]

In as much as your engine is newer than the ones i'm familiar with, if they
say 30 to 1 go with it, though it looks identical to the older model. Just the
same, however, get a spare fuel filter or two. The denser the oil mix, the
sooner they harden and clog up. If you weren't prepared for this to happen,
you might think something was wrong with the engine and start tearing it apart.
The filter's the 1st thing to check if it won't start.
I hear ya when it comes to expense; I'm an old man trying to live on a very
small stipend. I'm a tough old bird though; what I can't afford to buy I make
with my hands. Remember this, your hands and your legs are your best friends.
Take care of them.
I'm sure you'll get it working; the basic framework is sound, just needs some
tweaking.

 

[landuse]

In as much as your engine is newer than the ones i'm familiar with, if they
say 30 to 1 go with it, though it looks identical to the older model. Just the
same, however, get a spare fuel filter or two. The denser the oil mix, the
sooner they harden and clog up. If you weren't prepared for this to happen,
you might think something was wrong with the engine and start tearing it apart.
The filter's the 1st thing to check if it won't start.
I hear ya when it comes to expense; I'm an old man trying to live on a very
small stipend. I'm a tough old bird though; what I can't afford to buy I make
with my hands. Remember this, your hands and your legs are your best friends.
Take care of them.
I'm sure you'll get it working; the basic framework is sound, just needs some
tweaking.

Thanks. That info about the filter is good to know. If it happened to me, I probably would have thought it was the carb and started tearing into it like you said.

I have decided I am going to get this bike working properly no matter what.

 

[landuse]

So...this weekend I figured out what the problem was with my engine not working so well. One of my engine mounts was pressing againsst the flywheel, so it was getting jammed up and overheating. I had to take the engine off and grind down some of the mount to get some clearance for the flywheel. After taking the bike for a test run again, I was still dissapointed. It hardly moves on the uphills, but flies nicely on the downs.

I am going to replace the 1.5" roller with a 1" roller. I am just not too sure yet where I am going to get one.