How to Build a cheap friction drive bike

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
My engine came today, and even thought the ebay seller is a liar of monumental proportions, I was ready for him sorta. It took four hours but I got the engine through phase one. Rryobi 31cc engine instructions.

I am not going into all I had to do to make the engine run. Lets hope you score one that is already running. So lets begin at that point.

If it is on a trimmer you need to deconstruct it.
This is the first step.
1. Remove the steel shaft leading to the line feed head. Usually there are four screws holding it on. Just take them out and it should come right off.

2. With that removed, you will see a silver bell shaped piece. That is the outside cover of the centrifugal clutch. At the end of that hollow tube is a screw which holds the bell onto the drive shaft. To remove it you need to block the drive mechanism of the engine. To do that remove the spark plug and stuff a rope into the spark plug hole. Be sure to leave some of the rope sticking out so that you can remove it.

use a flat blade screw drive that will fit into the hollow tube to remove the screw. It should be easy enough to remove. Since you have blocked the engines ability to turn over it should work no problem.

3. Now that the bell is gone you should see the real clutch parts. There are a couple of springs. If you remove them the clutch will fall apart. When it does it leaves a jam nut with what looks like wings. Just take a vise grip and unscrew it. Now you have the first phase done.


This is how your engine should look at this point. The bolt I added it is a 3/8" fine thead cruiser axle bolt. YOU can use a bmx axle peg (not mountain bike) as a drive wheel. I am going to use something different and that bolt will hold it on (I hope)
 
Last edited:

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
No clutch for the build. This will be another of the most basic builds. After I test ride it if the the motor does okay, I'm going to install a big gas tank of some kind. I learned on that small engine that running out of gas is a no no for soooooo many reasons.


As for the distance, I will go down now and try to get you a measurement. 2 7/16 definitely less than 2.5 inches.

On the carburetor is the top line the one that goes to the tank or is it the one that goes to bulb. I might have them setup backward. Which might account for my gas leak. The more I think about it the more I am leaning that way.

ps I went and checked I'm pretty sure I had them backwards. Now tomorrow when it dries out I can put in some more gas and start it again. Then continue the build.
 
Last edited:

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Now back to de-constructing the engine.

Then next thing after you are sure your engine starts and runs. You need to strip the rest of the case away.


you want to remove those five bolts but save them you will use them again.


This is pretty much what you have at this point.


More to follow tomorrow. I have to wait for expoxy to dry..
 

Norman

LORD VADER Moderator
Jan 16, 2008
2,605
2
38
68
pampa texas
Man how long does it take for that epoxy to set I setting here awaiting the next installment of your build I want to see how you real back wood builders do it. Looks good so far.
to check the proper flow on those pumper carbs you can blow through one line on the barb that is the intake line and the other you can't blow into is the return line. be careful though as fuel does not taste good especially if its got Castor oil in it, if you know what I mean.rotfl. I did that last night working on a leaf blower the fuel line were hooked up backwards and the cylinder was about to come off along with a stuck ring on the piston its all better now and back in the owners hot sweaty hands. But his wallet is now lighter rotfl
Norman
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Well on mine if you hook the lines up backwards the gas just runs out the bottom. I think I have it figured out now the intake is the bottom inlet and the return is the top one. At least that is the way the gas doesn't pour out and it does run.

I always let my jb cure over night if I can. It seems to work better and be stronger that way. It dries to the touch in a couple of hours but I don't trust it.

I'm still debating that 2x2 frame for the engine. Another reason I didn't rush into it. Now that the pull chord is off, I will have to wrap a string around the drive wheel to start it by hand. I might not even bother, just go right for the drag start.

Norman will the extra 6cc make any difference in the engine performance.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
Building the motor mount.

I decided just for fun to use a 2x2 as part of the motor mount. If it tests out alright I will probably use more wood in the build. There are several parts of this mount frame I could easily replace with wood.

anyway photo one shows the kind of hinge, the 2x2 and a shelf bracket they are all part of the mounting hardware.


The next image shows mending strips of steel from home depot. Since I don't cut and weld I had to buy all these metal parts. Some I had to adjust and some the bolt holes lined up pretty well.


Its mostly trial and error but what you need to do is to mount the hinge either to a shelf bracket or a mending strip and shelf bracket depends on what you need to do to make it work.



Now you can test fit it to the bike. The shelf bracket gone on at this time as well. It is to tie a box configuration together.



The next thing to do is tie in the existing throttle cable and wire a kill switch. that's next time.

If there are any questions please ask it will help me explain this more fully.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
another view.


The tension is supplied by an old fender brace attached to the non motor side of the frame. It also helps keep the motor straight (I hope)
 
Last edited:

hillmanrocks

New Member
May 18, 2009
2
0
0
Earth
You rock man thanks for all this info this is great i am gona get started on my own too. I like your foot peg idea prolly last way longer then those cheap pins they sell online with the kits and you could paint art or design on the wood you use in the build , wow again dude thanks
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
I dont buld these anymore but I lifted them from the wheel and used a rope around the drive wheel usually to start them
 

aaronmorg

New Member
Jun 8, 2009
13
0
0
Louisiana
Do you think I could get a small materials list?

I have the engine and I can take it apart like you said.

Can you jot down on this thread what I will need to go get from Lowe's or Home Depot?

And I'd much rather use metal, I don't have any wood, haha.

Thank you,
Aaron

P.S.- This is something to pass my time until the 18th, which is when my badass kit ships. Woot. HOpefully this doesn't fall apart on me laff
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
A couple of pieces of angle iron to hold the motor..... Some nuts and bolts..... A henge.....a spring....Something to use as a drive wheel.....

That should get you started...
 

Reirol

New Member
Jul 9, 2009
3
0
0
Earth
I was perusing the forums and found this thread. I realized that, I had created a rig with the same engine a few months ago. I did a few things differently:

It isn't necessary to take the entire housing off and create new holes to mount the engine on. Just tap out the existing holes in the plastic housing with a large fine thread, Then add a long fine thread bolt to it. Those mounts are actually alot more stable than I thought they would be. I thought it would be nice to keep my clutch, being that it's nice starting the engine while not moving. Makes coming to a stop at stop signs much easier. So I added 1 inch steel hex standoffs to those plastic mounts and bolted the whole thing to the motor. This allows me to keep my clutch. That particular engine comes with quite a large clutch.
Here are some pictures of the rig:

The rig itself:
Part 1.jpg

Here's a picture of how I mounted the engine:
Part 3-1.jpg
 

Roadkill

New Member
Feb 14, 2009
242
0
0
Roadkill, USA
Nice build Deacon. Can you post some pics of your new trailer that pushes you? I think that is what is on your avatar.

I read your blog a bit. This healthcare is made to look good but with no jobs it is required by law to PAY the government insurance czar or get a $1000 fine.
 

el toro

New Member
Aug 1, 2009
8
0
0
wa
nice. so hay Reirol how did you mount the peg to the bell housing? i wanted to do the same but was not sure how to go about it.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
3
0
north carolina
In my case i took it off and mounted to the drive shaft the ryobi it will just screw on. Some of the others have a different size shaft.
 

el toro

New Member
Aug 1, 2009
8
0
0
wa
yah thats what i did on my build. sure is easy that way. i was just trying to use the clutch so i would not have to use a disengage system. mine is a 4 stroke. hard to find parts for this one