# Home made mini bike.



## Peyton Price 17 (Nov 11, 2020)

me and my friends want to start a little mini bike shop. i am not self promoting as i wont say were you can get them. this is just for all of the stuff i need to make one and anyone with experience to give me some advise. this is what i have so far.


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## Peyton Price 17 (Nov 11, 2020)

i found a throttle that will fit.


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## FOMOGO (Nov 11, 2020)

Your probably going to want to build a frame jig. You can go through a lot of tubing using the hit or miss method. You will have to come up with some sort of fork assembly, and steering head and bearings which may also be available on line. Kind of a right of passage for young folks to build something fast, loud, and dangerous. As you get older the HP, and dollar figures rise accordingly. Cheers, Mike


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## Peyton Price 17 (Nov 11, 2020)

FOMOGO said:


> Your probably going to want to build a frame jig. You can go through a lot of tubing using the hit or miss method. You will have to come up with some sort of fork assembly, and steering head and bearings which may also be available on line. Kind of a right of passage for young folks to build something fast, loud, and dangerous. As you get older the HP, and dollar figures rise accordingly. Cheers, Mike


i was thinking of making a jig so that the sides are the same. i have a roller and bearing store down the road. i was thinking of maybe using an old bike steerer tube. but then i would have to bend the fork out ward. i think that making a custom one is a better idea like what you said. thank you very much.


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## Peyton Price 17 (Nov 11, 2020)

i found a frame that i like. it should be bigger than the one i have. it has a 3.5hp. the frame design the right size for the 212cc engine.


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## brino (Nov 11, 2020)

Peyton,

That should be fun as a project and to ride!

When I built a go-kart for the kids, I used square steel tube for the frame. As the corners are a little easier to cut and weld, and you have flat faces to bolt things to. I know bikes all use round tube.

Is the frame going to be bent tube, or cut and welded?
If using round tube and welded joints, a coping cutter would be of benefit.

https://www.instructables.com/How-to-Miter-Cope-a-Round-Tube-by-Hand/
https://www.hobby-machinist.com/threads/hole-sawing-pipe.67577/#post-564989
https://www.hobby-machinist.com/thr...d-you-do-in-your-shop-today.14637/post-253337

Have fun and be safe!

-brino


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## Peyton Price 17 (Nov 11, 2020)

brino said:


> Peyton,
> 
> That should be fun as a project and to ride!
> 
> ...


i am still deciding on bending or cut and weld. i think that cut and weld would be easier with sqaure tube. ill check the price. 5/8 tube and 1 inch tube with 1/8 wall is 2.06 per foot. i will use tube and cut and weld. it seems to be better than pipe at almost everything.Thank you very much.


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## matthewsx (Nov 11, 2020)

You will want to buy a tubing bender if you're building frames but it may be better to buy them depending on how many units you are planning to build.

These guys have been in the business longer than I've been alive.



			Azusaparts
		


They were one of the best suppliers I had when I ran my go-kart company, super reliable and easy to work with. Give them a call (yes, call) and see about setting up an account. 

There are tons of other tips I could give you but have to get to work soon.


Good Luck,


John


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## Winegrower (Nov 11, 2020)

I did this very thing when i was in high school hundreds of years ago.   i made a bunch of drawings and my dad had a machinist make the parts and a welder make up the frame with my cut up tubing.   It was terrific,  And over the years as thing slowly fell apart and got patched up, it morphed into a direct chain drive, a rope to wrap around the crank for starting...straddle it, hold up rear wheel, pull to start, drop the wheel and go.   Amazing we never lost a finger or broke any bones.

It’s still about the coolest thing I ever did.


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## MrWhoopee (Nov 11, 2020)

I believe those Predator motors are rebadged Lifans, which are Honda clones. I have a Lifan on a used chipper that I bought last year. It has obviously had a hard life. I was told it powered a mini bike before the chipper and was not treated gently nor well cared for.  I continue to be impressed with how easily it starts and how well it runs.

Cut and weld is simpler in small quantities, bending is stronger and more reliable in use. Once the tooling and process have been developed, bending is easier and quicker. 1/8 wall is probably overkill, .093 would be more than sufficient and much easier to bend if you decide to go that way.


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## rwm (Nov 11, 2020)

Everybody around here is getting electric mini-bikes. Something to think about.



I saw one that was classified as a scooter to circumvent the law on street use. 
Robert


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## C-Bag (Nov 11, 2020)

What have you got for cutting and welding?


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## Bi11Hudson (Nov 11, 2020)

An interesting proposition, to say the least. I don't have any usable advice but do have some thoughts about how I would approach the scenario if I were to do it myself. There are many non-technical factors to be considered, not the least of which is location. Be it urban, suburban, rural, etc. Another being potential customer base, age, gender, race, disposition, etc. On the aspect of construction, my personal disposition would become a major factor. 

Bearings, for example. . .  For myself, I would use a bearing common throughout the machine. Start with common trailer wheel bearings. They would be grossly oversized for a "mini" application. Adjustments would have to be made to allow such a large bearing to be used. When adapted to the frame, thay then become an "inexpensive" yet quite reliable component. By using the same bearing for wheels _and_ steering, the parts overhead is reduced to an easily managable degree. There are other reasons for that particular part as well. Not the least the common availability of such a part.

Another factor to consider is power plants, engine(s). If I were to design such a device, I would choose a line of products of varying sizes, say 5HP, 12HP, and 25HP. All three having a consistant mounting technique. The mounting "attachments" appropiate to all three attached to all frames so they could be updated as desired. Both as new models as well as at customer request. When a larger engine is desired, it becomes a simple matter of unbolting one and bolting on another.

Some of the desired consistancy across models would raise the initial cost some small amount. However, long term it would allow for an "aftermarket" setup for "updating". Many mechanical devices consider the real profit to be in replacement and updated parts more so than the original cost. Specifically the automobile industry. . . And it would definately have an effect on inventory.

Such dreaming on my part should be taken with a grain shaker box of salt. It being purely speculative. And definately not advice.

.


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## Peyton Price 17 (Nov 11, 2020)

C-Bag said:


> What have you got for cutting and welding?


for cutting i have a hacksaw but will convert a wood band saw to cut metal. for welding my pa has a big mig and my dad wants to get a tig.


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## C-Bag (Nov 11, 2020)

Peyton Price 17 said:


> for cutting i have a hacksaw but will convert a wood band saw to cut metal. for welding my pa has a big mig and my dad wants to get a tig.


I get believe me it’s hard to pick the most useful basic equipment when first starting. One of my first basics was a 4x6 horizontal bandsaw. For cutting long smaller stock and for cutting angles it’s necessary. I love my converted vertical wood bandsaw but for long stuff it’s not ideal.

I love seeing young people get enthusiastic about making and you never know where it will lead you. But IMHO trying to determine where it will go before you’ve taken the first step might not go where you envision. Henry Ford didn’t picture making auto dealerships when he was tinkering. Same with Robert Bosch. Learning the basics and making something you are enthusiastic about is the first step to doing what you love. If this is already what you were doing I apologize for stating the obvious.


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## Peyton Price 17 (Nov 11, 2020)

i found some tires. i will press out the bearings for the rear tire and it should be 3/4


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## Peyton Price 17 (Nov 11, 2020)

Peyton Price 17 said:


> i found some tires. i will press out the bearings for the rear tire and it should be 3/4
> 
> 
> 
> ...


i could use the bearings that i will have to remove for the fork.


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## CluelessNewB (Nov 11, 2020)

I'm not sure what the 26 tooth sprocket is for,  hopefully you are not considering them for direct drive on the rear wheel with a 12 tooth clutch.  Typically you would want something like a 6:1 reduction so a 72T rear sprocket.  Personally I think those wheels and tires designed for a slow speed hand truck will be a very big disappointment in short order.


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## Peyton Price 17 (Nov 11, 2020)

CluelessNewB said:


> I'm not sure what the 26 tooth sprocket is for,  hopefully you are not considering them for direct drive on the rear wheel with a 12 tooth clutch.  Typically you would want something like a 6:1 reduction so a 72T rear sprocket.  Personally I think those wheels and tires designed for a slow speed hand truck will be a very big disappointment in short order.


i found a new sprocket like you said and a new drive wheel.


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## tq60 (Nov 11, 2020)

All good but avoid reselling as liability is problem now.

For personal use fine bit s customer gets hurt and big trouble.

Possible ways to avoid but requires consideratio n and planning.

Sent from my SAMSUNG-SM-G930A using Tapatalk


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## eugene13 (Nov 11, 2020)

Go for it Peyton, I built my first mini-bike in 1965.  No clutch, no brakes, bicycle front end, hand truck wheels and a used engine that was hard to start.  What an adventure, scrounging up the parts and talking a friends dad into letting me use his welder.  The only new part I bought was a rear wheel with a built in sprocket, and my future brother-in-law was the only one to get road rash.


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## Peyton Price 17 (Nov 11, 2020)

tq60 said:


> All good but avoid reselling as liability is problem now.
> 
> For personal use fine bit s customer gets hurt and big trouble.
> 
> ...


i was thinking about selling some but liability is the issue. if they get hurt then they could sue a 12 year old making some mini bikes and they use it wrong. i might sell some on Facebook or  Craig's list so that i cant get sued but i will have them sigh wavers saying that they are responsible for injury's. i might just make some for me and my friends.


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## Peyton Price 17 (Nov 11, 2020)

eugene13 said:


> Go for it Peyton, I built my first mini-bike in 1965.  No clutch, no brakes, bicycle front end, hand truck wheels and a used engine that was hard to start.  What an adventure, scrounging up the parts and talking a friends dad into letting me use his welder.  The only new part I bought was a rear wheel with a built in sprocket, and my future brother-in-law was the only one to get road rash.


me and my friends screwed some wood together and made a 3 wheeled cart. we would ride it down hills. we brought a tractor to bring it back up and the drive belt snapped at the bottom of the hill. then some police showed up and we told them what happen and they laughed and told us good luck.


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## matthewsx (Nov 12, 2020)

So, starting from the top....

The Predator motor is from Harbor Freight and goes on sale for $99 pretty often, don't know if it's a Lifan but definitely a clone of the Honda 200cc engine and there are a ton of parts available. I used to sell big valve, ported heads for them all day long.

The throttle not only needs to fit on the handlebar but you'll need to modify the linkage on the engine to work with it. You'll very quickly want to remove the governor as it will fight with your attempts to use the throttle like it should work, this involves opening up the engine and pulling out all the bits which make it work because just disconnecting it on the outside will lead those parts to breaking and destroying the inside of your engine. Any modifications beyond this or attempts to run past ~3500 rpm should be accompanied with a billet aluminum flywheel, actually a good idea for any Chinese built motor that will be mounted between your legs....

Don't skimp on the clutch, they mostly all look alike but the one to buy is the MaxTorque, the knock-offs like the one you linked to may look the same but won't hold up to the abuse in my experience. You can also call them to get advice for your application rather than just winging it, another company that's been around longer than I've been alive.





__





						Max-Torque Clutches
					





					maxtorque.com
				




If you're not sure you will be building a whole bunch then look into buying a frame rather than building one, if your dad really wants to help and thinks building a frame is within reach then go ahead but I doubt you'll get it done for less than the $149 that Azusa charges for theirs. The wheels you've found are not what you'll want, take a look at what Azusa sells with their kits, you may have some cool ideas but mini-bikes have been around a long time and what works is pretty well known, like you need a brake built into the rear wheel so you can stop.



			Minibike Kits » Product categories » Azusaparts
		


I don't want to throw water on your fire but you'll need to do a bunch more research before you're ready to spend the first dollar on parts for this project. Just a quick word on liability insurance, you'll never get product liability coverage that will even be close to affordable. I had trip/fall insurance for my retail store and coverage for my inventory and tools but nobody at the time (2004) would even think of writing a policy that would cover people doing stupid things with a mini bike or go kart. In my case I was selling to people who raced at tracks which provided insurance with the entry fee. For a mini bike everyone is pretty much on their own if they get hurt (I have crashed one and it definitely does hurt). However, I'll give you the skinny right here....

What you do is every invoice carries a disclaimer that states the product is only to be used on a closed course under proper supervision, yada, yada, yada. But, in that language you put the phrase "all claims are subject to binding arbitration in the state of ____". This was given to me by a major importer of karts and minibikes for the consumer market, not racers. What it does is tell any lawyer that they won't get to sue you at a jury trial which is where the big settlements come from. Therefore the case won't get taken up and you'll be protected. Now, I'M NOT A LAWYER so take it for what you will. This won't protect you from gross negligence but it worked for me.

There are a whole bunch more things I could tell you, but realize you're probably just gonna end up building a few bikes for you and your friends. The market just isn't that big and you have to compete with motorcycles, quads, side by sides, snowmobiles, jet skis and a bunch of other stuff people can do with their free time. So build whatever suits your fancy, there are a bunch of people on here that will cheer you on and offer solid advice.   


John


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## Peyton Price 17 (Nov 12, 2020)

matthewsx said:


> So, starting from the top....
> 
> The Predator motor is from Harbor Freight and goes on sale for $99 pretty often, don't know if it's a Lifan but definitely a clone of the Honda 200cc engine and there are a ton of parts available. I used to sell big valve, ported heads for them all day long.
> 
> ...


i know i have to make a linkage but dont know how. i found the same clutch


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## fixit (Nov 12, 2020)

I built this years ago 206cc honda (scary fast had to use governor to keep the speed down) mostly bed frames & a little pipe. Had many offers to sell it but was concerned about liability. If you intend to fab and sell them get some good insurance.


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## Peyton Price 17 (Nov 12, 2020)

matthewsx said:


> So, starting from the top....
> 
> The Predator motor is from Harbor Freight and goes on sale for $99 pretty often, don't know if it's a Lifan but definitely a clone of the Honda 200cc engine and there are a ton of parts available. I used to sell big valve, ported heads for them all day long.
> 
> ...


my dad wants the shop done in the spring. the guy built a 20x12x16 shop in 2 weeks.


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## Peyton Price 17 (Nov 12, 2020)

i found a new clutch that is  in stock. my friend said he will buy the engines.


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## tq60 (Nov 12, 2020)

If you sell PARTS that others make liability is much easier.

Do notresel a home built frame, do resell readymade.

Others offering great advice.

Get crazy with "your unit" to inspire others.

Sent from my SAMSUNG-SM-G930A using Tapatalk


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## matthewsx (Nov 12, 2020)

Peyton Price 17 said:


> i found a new clutch that is  in stock. my friend said he will buy the engines.
> 
> 
> 
> ...



I'm still going to encourage you to CALL the suppliers directly. Amazon is fine for gathering info but it won't help if you eventually want to sell parts to your friends. Establish yourself with the suppliers if you possibly can and find out about wholesale pricing. Even if you don't end up buying from them you will gain knowledge from talking to others in the business. Azusa sells clutches too....

John


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## Peyton Price 17 (Nov 12, 2020)

tq60 said:


> If you sell PARTS that others make liability is much easier.
> 
> Do notresel a home built frame, do resell readymade.
> 
> ...


ok from azusa i can get a frame and fork for 150   .


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## matthewsx (Nov 12, 2020)

Peyton Price 17 said:


> ok from azusa i can get a frame and fork for 150   .
> 
> 
> 
> ...



Yes, ready to paint and assemble with whatever parts you like. Do look at the parts offered too, they are well matched to the application and competitively priced. Give them a call and tell them John from Heartbeat Racing/TMS Racing referred you.

John


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## matthewsx (Nov 12, 2020)

They have good prices on safety gear too, WEAR A HELMET!!!!

Now get back to studying 


John


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## Peyton Price 17 (Nov 12, 2020)

matthewsx said:


> They have good prices on safety gear too, WEAR A HELMET!!!!
> 
> Now get back to studying
> 
> ...


i always wear a helmet and cracked one on my mountian bike.


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## Peyton Price 17 (Nov 12, 2020)

i think that i will buy the 8 inch wheel kit mini bike. all i need is an engine. the kit comes with a 72t sprocket on the drum brake. this is awsome.


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## fixit (Nov 12, 2020)

Check STENS for parts I used the for years great prices and good delivery


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## matthewsx (Nov 12, 2020)

fixit said:


> Check STENS for parts I used the for years great prices and good delivery


Stens was great supplier for my business too, you can usually get either them or Prime Line from your local auto parts place.

John


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## Bi11Hudson (Nov 13, 2020)

Just a thought about liability. What is the difference between "new" and "used-low mileage"?
.


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## keeena (Nov 14, 2020)

If you build it and it has 2 wheels, I will ride it!


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## matthewsx (Nov 14, 2020)

Bi11Hudson said:


> Just a thought about liability. What is the difference between "new" and "used-low mileage"?
> .


If you built it, very little.

If the OP is building anything he will do well to either buy from an established supplier and sell "parts" in "kit" form. The "binding arbitration" clause mentioned an my earlier post is highly recommended no matter what....

I've run several businesses with significant liability issues and making sure you have a solid contract for every transaction is paramount. I once had a customer try to scam me on a boat he dropped off at my shop and the simple wording on the form he signed kept him from collecting anything. That and a call from the local police department after he threatened me....

John


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