Weed Eater Bike

[xXPhasemanXx]

I want to make a weed-eater bike since its much cheaper than making an off road mini bike. I still want to make an off road mini bike, but I need something before the end of the month. I'm not sure what engine I'll be using yet, but I'm hoping for either a sx-135 or a st-155. The reason why I'm posting this here is because I want your guys opinion on whether I should use a friction driven bike or a chain driven bike. Friction bikes are nice but a lot of power is lost to well...friction. I don't have anything to weld with, so I have to use bolts, bars, and other things in order for this to be done. Excluding the engine, would I be able to get this built under $75 (Estimates please, I don't want to hear "Depends on location"). I would like it to be chain driven, but if it comes down to it, I'll take a friction-based bike. All the videos on YouTube that say "How to build" are all low quality and they don't go too much into depth. I'm also not sure what parts I would need for the project.

 

[landuse]

I did a friction drive bicycle a little while ago. Have a look at my thread HERE.

I would also have preferred a chain driven bike, but it was going to be a lot more complicated then. I did a lot of research before doing it, and www.motorbicycling.com helped me a lot. There are several threads there that deal with weedeater bikes.

 

[xXPhasemanXx]

Looks good, what top speed could you get on your friction based?

 

[landuse]

Looks good, what top speed could you get on your friction based?

I never really mesured it. It was just an assist to pedaling. I would never be able to get up any sort of hills with it. If I was on a flat I could probably get 12-15mph out of it

 

[xXPhasemanXx]

I never really mesured it. It was just an assist to pedaling. I would never be able to get up any sort of hills with it. If I was on a flat I could probably get 12-15mph out of it

That's not bad actually Since I live in the flatlands I won't need much uphill power. I'm hoping I can get above 20km/h on the thing. I'll be going to use this design

http://www.youtube.com/watch?v=vDqtc6c0QJE​

So far I have come up with these parts/tools that I'll need to finish, does anyone else see something I've missed?

• 2 U-bolts
• Iron Bar (Preferably L-shaped, if not, bend one)
• Metal Saw (For cutting metal)
• Nuts/Bolts
• 1 Turnbuckle (For engine tension)
• C-clamps (For holding metal for drilling perparation)
• Vice Grip
• Bike Peg (Rough Edged, not smooth)
• Drill bits (For metal drilling)
• Metal Cable
• 1 Spring
• Engine

 

[mckutzy]

I'd say go to the flea market for all the small bits.

 

[xXPhasemanXx]

I'd say go to the flea market for all the small bits.

Don't have anything like that here, I'm probably just going to go Home Depot, Rona, or Canadian Tire. Most likely Home Depot since it's closer to where I live and its where the guy in the video got all his stuff.

I like the design above because I can turn it into a pedal bike at the same time (Since the peg will turn all the time when it is on). Consider this, does the engine just turn on as you pedal? Or would I need to pull start it each time?

Edit: Bad news, looks like the weed eater I wanted was already sold and the person never removed their ad But I found another one for $40 and I won't be able to get it Saturday (Hopefully). But I'm going out to get all the parts that I need for this project later today. The weed eater I'm getting is a mcculloch 31cc.

 

[landuse]

Don't have anything like that here, I'm probably just going to go Home Depot, Rona, or Canadian Tire. Most likely Home Depot since it's closer to where I live and its where the guy in the video got all his stuff.

I like the design above because I can turn it into a pedal bike at the same time (Since the peg will turn all the time when it is on). Consider this, does the engine just turn on as you pedal? Or would I need to pull start it each time?

Edit: Bad news, looks like the weed eater I wanted was already sold and the person never removed their ad But I found another one for $40 and I won't be able to get it Saturday (Hopefully). But I'm going out to get all the parts that I need for this project later today. The weed eater I'm getting is a mcculloch 31cc.

You don't need to pull start the engine. If you look at my build you will see that I removed the pull start completely. I just bump start it when I start pedalling. It is like push starting your car.

Just be careful when pedalling your bike with the engine off. If the PTO is turning all the time with it off, the engine is getting no lubrication and can easily seize up.

Google scissor clutch for a motorised bike. I was going to do one, and got all the material I needed, but then never got around to it. It allows you to pull the engine off the back wheel

 

[Krustalien]

I built a friction driven bike, very simple with no welding. Just a few bars, a few bolts, a piece of floorboard (motor mount) and a large spring. It does slip a little and the engine will bog if you jump to full throttle at low speed, but top speed on the flat was/is about 25mph. the motor isn't a weedeater/chainsaw type, mind, it's a slightly weird low rpm 2 stroke, 2.3hp.

Am building a motorised bike with a friend that uses a minimoto engine, when that's built I'm going to rebuild my own with that weird 2 stroke and if I can, use all 18 gears (assuming the mechanism stands up to it!), so I'll be following this thread closely for inspiration.

Good luck!

 

[xXPhasemanXx]

Thanks for the help, I went out and bought tools last night, the only thing I need now is a vice grip and the engine along with a new tire for the bike (Old one is broken). I'm hoping that I can get the whole thing done tomorrow if I get the engine on time.

Edit: These are what I'll be using to mount the engine onto the bike, It looks like it won't fit, but I'm sure I can make something work out with some bending and drilling.

Edit: I got the turn buckle onto the bike but it seems a little small, I'll need to get a bigger one, or an extension. Sadly the bike I wanted to use won't be being used because I would need to order a completely new rim for it and I just want to get this done and over with so I can sell it (I need some money) and after that I can build a new one.

 

[xXPhasemanXx]

So as I was mounting the bike peg onto the bolt that sticks out of the engine it got stripped. I was tightening it an tightening it jsut for good measure and then...POOF. It stripped itself. I didn't even tighten it that tight either, my bike tire can be tightened more than that thing. The good news is that it's only stripped for the first cm or so. Would you guys recommend I get this to fix it?

Live and learn as a first timer huh?

Edit: I added in the photos, as you can see, the engine bolt has been stripped at the very top and I can't put a bolt onto it while the big peg is on there.

Edit: I manages to find a good spot to mount the end of the original throttle cable, and I've also put the kill switch next to it. You can see the throttle cable on my finger

I also have some questions about this one gas tube on the right

It came out of something while I was mounting the engine and I was wondering if it is important? You can see what it looks like from the inside the tank. Ignore the green tube, but look at the white bump inside the tank. From what I can see, no gas can get inside but it obviously can or else there would be no tube there. (Best photo I could get)

 

[xXPhasemanXx]

Would I need an exhaust pipe for this project or should I be fine?

Also take a look at my previous post (Sorry for bumbing, I just would really like the feedback as this is the only place I'm getting help from.)

 

[J_Walker]

Would I need an exhaust pipe for this project or should I be fine?

Also take a look at my previous post (Sorry for bumbing, I just would really like the feedback as this is the only place I'm getting help from.)

No its fine. no bumbing hated.

Does it still have the stock exhaust "box" ? if so, then you're fine.

Also, one of the gas lines is a return line I think..

As far as tightening down something. http://compare.ebay.com/like/350693248077?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar Red loctite.. No worrying about the screw ever coming off.... LMAO

Or get blue, if you would like to get it off at some point in its lifetime.. I use red when I know, somethings gonna get hot, and cooled. as blue is pretty easy to get off when you heat it up with a heat gun.

Red, eh. that's a joke. better have a very long pipe to torque that sucker off!

But when you tighten something down. finger tighten it. then use a wrench to "push tighten" it. normally a turn or two. before it starts feeling tight, when it feels tight. do a 1/4 turn. and leave it at that. General rule of thumb.

 

[xXPhasemanXx]

No its fine. no bumbing hated.

Does it still have the stock exhaust "box" ? if so, then you're fine.

Also, one of the gas lines is a return line I think..

As far as tightening down something. http://compare.ebay.com/like/350693248077?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar Red loctite.. No worrying about the screw ever coming off.... LMAO

But when you tighten something down. finger tighten it. then use a wrench to "push tighten" it. normally a turn or two. before it starts feeling tight, when it feels tight. do a 1/4 turn. and leave it at that. General rule of thumb.

For the red bolt tightener, do I still need to tighten the bolt? Because I can't even get a bolt back on. Thanks for that general rule though

I'll check for the box exhaust tomorrow as I'm at school and it's late. I'll also check the gas lines.

Thanks for the help

 

[xXPhasemanXx]

One Problem Resolved

I figured out where that gas line went. It broke as I put the plastic casing back on. It's kinda hard too see but the line was squished in between the engine and the cover.

Also my previous issue hasn't been resolved. Because of the stripped bolt on the engine, I can't get the nut even close to tight enough to put the bolt tightener onto it. If I do that, it will just wobble in a tilted axis and not make a smooth ride.

Edit: MY dad said the engine is garbage because that bolt is stripped at just the first part; is that true? Do I need to get a whole new engine or could I use this instead?

 

[xXPhasemanXx]

I'm still stuck on what to do about my stripped engine bolt. Does anyone know a way to fix it or will I have to weld the big peg on because of that?

 

[mckutzy]

I reckon it be F-ed, Unless you have another crank. If you use a standoff, it will have to be torqued anyways and that might worsen the problem, not to mention it'll put more torque on the bearings and the whole motor itself.
You might just have to get another one.

 

[jace]

just file the jacked up threads off, and use the good ones?

 

[xXPhasemanXx]

just file the jacked up threads off, and use the good ones?

It's too short

I reckon it be F-ed, Unless you have another crank. If you use a standoff, it will have to be torqued anyways and that might worsen the problem, not to mention it'll put more torque on the bearings and the whole motor itself.
You might just have to get another one.

I'm trying to avoid getting a new motor but if I really have to I will.

 

[dnuccio]

you could use a die to cut some new threads on the crank