Minibike build.

[B.M.800]

Most likely a long term project.

So Ive been thinking a little bit about building a mini bike after my cart is put together...
And after seeing this video, I just might be dead set on it. :arf:

Now I dont have much to start with, just a 5HP B&S, a bit of metal, and possible rear wheel and tire(20X11)

I need some ideas for a good frame(light/sturdy) and just any other information I might need.

Thanks!

{EDIT} whoa, thought I put that video in a link... ?


SO, ive decided not to build a minibike... atleast not right now.
Thanks for everyones input

 

[r97]

well having an engine and metal is a good bit to start with. 20x11 would be huge! lol. just look around the forum, you can find lots of info on how to build a mini bike. also i believe the bike in that vid is geared 8 to1 if i recall.


EDIT:
different fork, sq tube, black and orange paint, and you got pretty much the same bike,
http://www.diygokarts.com/chopper-plans/mini-chopper.html

 

[robbie]

That's a pretty cool little bike in the video. Your 20x11 tire is going to be a lot better than the dinky wheels that end up on most mini bikes, but you'll probably have to include a jack shaft to get the correct ratio.

 

[B.M.800]

How would I go about gearing it? Id like to be able to go atleast 25mph, and be able to do hills(loose rocks dirt somewhat steep) with ease.

Im going to try to go to the scrap recycling and maybe look for some stuff... what kind of stuff should I look for?

Thanks.

 

[MacfarlaneRacers]

How About A Bit Of Weight At The Back For The Wheelies LOL Or Another Engine. (LESS POWERFUL)

 

[robbie]

That's what I was thinking. The bike in the video is a disaster waiting to happen if you don't know how to be easy on the throttle. When you build your bike, maybe you want to make sure your rear tire is behind you at least a little bit.

When you go to the scrap yard, see if you can get a steel bicycle frame for the steering joint. This would be a lot better than the standard mini bike "bolt through a tube" setup. Also, see if they have a wrecked motorcycle or 3 wheeler. These may have good foot pegs or brake pedals.

 

[r97]

why less powerful!? more power!!!!! lol
you can prob get the speed /torque you wan't if you gear it a bit low and remove gov. with 5hp, and 20" tires geared a bit low, you will wan't a jack shaft for sure, i think between a 12 to 1 and a 10 to1 ratio

 

[B.M.800]

Im planning on putting some sort of whellie bar on, atleast untill i get used to it.
I have a few junk pedal bikes layin around. How much would you guess I could get a junk motercycle or 3wheeler? as of now I dont have much $ to spend, Christmas is comming around soon... Im hoping to not spent over 100$ if i can, ofcourse if I can get a junk something i caould still use it for another project

{EDIT} How much modding could a honda 6.5 take?

 

[porsche930dude]

your best bet is to look on craigslist for an old bike they can be had pretty cheap like 30-50$ fix it up and modify it to your liking. Its a hell of alot more involved building a minibike from scratch.

 

[B.M.800]

Well, thats why Id like to make it from scratch... because it is more involved. I need something to keep up with my buddys kart, but not leave im in the dust.

 

[porsche930dude]

well go for it then. Just dont skimp on the details itll pay off in the end. Usually minis are made of 7/8" tubing. im not sure of the thickness or strength.

 

[robbie]

I'm not suggesting that you buy a motorcycle or 3 wheeler. If you go to a scrap yard you'll usually be able to pull parts off of them. You can also get shafts, pedals, wheels and such from old riding mowers. They'll either sell everything by the pound for scrap price or they'll make up something on the spot. Usually you can assemble a pile of foot pedals, handlebars and whatever else, and they'll say "Ummmm, how about 15 dollars," or whatever price pops into their head.

At the junk yard near my house you can buy big steel pieces for 20 cents a pound. If you have things to build, the thing to do is throw your go-kart and mini bike parts in the truck on days when you're buying pipe, I-beams and other large pieces of steel. They're almost free that way.

 

[B.M.800]

Porsche930dude: I don't intend to skimp out.

Robbie: Dang, wish that was near me. I'm gonna see if we have any more crap i could use .laying around tomorrow.

Thanks for all the input guys.

 

[robbie]

Look in a phone book and online. Surely you have big scrap yards somewhere nearby in Pennsylvania.

 

[B.M.800]

We do, its just finding a good day and the time to go over and look.

What size chain should I use? And how should I gear it?

What size wheel and tire would be good for the front?

Thanks.

{EDIT} Wait, I was wrong about the tire size... is 21X11
I also have a 22X11 for a spare maybe... The tires themselves are kinda rough.

{EDIT 2} Heres a design for the frame. Sorry if it takes so stinkin long to load.
The different shapes show where the different parts go. What do you guys think?

Thanks.

 

[B.M.800]

Heres my options for rear tires. Yes I know one is missing a valve, neither of them hold air now. Do you think I could get that Slime stuff top fix that, or just get a tube?