FIRST BUILD- Vintage Bike, and TECUHMSEH 3.5HP GO-KART MOTOR

Hello guys! I'm Christian, and 16 years old. I have blacksmithed for 9 years and been welding for about 9 monthes. I had an old bike that my grandfather gave me and an old Tecumseh 3.5 motor that went on my Go-Kart. So what do I do? Combine them! I am a new member, and this is my first post, and my first build. So please give me any tips and ask any questions! Thanks! I'm taking the pedals off, so I guess it's legally a motorcycle xP
P.S. My mig welder is broke and I'm to lazy to fix it, so I am using my SMAW welder, so most of these are tacks till I get the mig welder working cause the tubing is so thin and all I've been doin is burning holes. xD So sorry if the welds look nasty.

Gear Ratio question: I have a 12 tooth gear on the clutch that will go to a jackshaft that will go from an 18 tooth (connected to the clutch) to a 52 tooth which will run to a 24 tooth attached to the rear tire. How will this perform, or should I use a different gear on the jack shaft? The 12, 52, and 24 are pretty permenant, cause I'm using the original 10 speed gearing the bike came with. But I'm just asking how one set up will act to give me an idea on how my bike will perform. Cause I am going to make mine shiftable using the shifter the bike has.
Wellp, Here it is!

 

[curtisfox]

You might get some ideas off this site: http://www.vintageprojects.com/mini-bike/Power-Bike-plans.pdf Snowmobile springs older three leaf ones work good and looks more athentic. Also used is gulf cart springs I have 12" one. I got frome this guy? check out his build. http://motorbicycling.com/showthread.php?t=19434 Its a lot like yours................Curt

 

[AnvilBlockForge]

Another Gear Ratio Question xP

A 12-tooth clutch sprocket chained to an 18-tooth jackshaft sprocket?
That's 18/12 = 1.5:1 gear ratio.

A 52-tooth jackshaft sprocket linked to a 24-tooth rear wheel sprocket?
That's 24/52 = .4615:1.

1.5 x .4615 = .69:1 total gear ratio.

The engine will NOT move the bicycle.

What if I replaced the 18- tooth jack shaft sprocket with a 39-tooth sprocket and kept everything else the same? Would that be better?

The 12-tooth clutch sprocket and 24 tooth rear sprocket are permanent, but I have 13-tooth, 54-tooth, and a 39-tooth sprockets that I can put on a jack shaft. What would be the best combination?

 

[5-7HEAVEN]

Hello guys! I'm Christian, and 16 years old. I have blacksmithed for 9 years and been welding for about 9 monthes. I had an old bike that my grandfather gave me and an old Tecumseh 3.5 motor that went on my Go-Kart. So what do I do? Combine them! I am a new member, and this is my first post, and my first build. So please give me any tips and ask any questions! Thanks! I'm taking the pedals off, so I guess it's legally a motorcycle xP
P.S. My mig welder is broke and I'm to lazy to fix it, so I am using my SMAW welder, so most of these are tacks till I get the mig welder working cause the tubing is so thin and all I've been doin is burning holes. xD So sorry if the welds look nasty.

Gear Ratio question: I have a 12 tooth gear on the clutch that will go to a jackshaft that will go from an 18 tooth (connected to the clutch) to a 52 tooth which will run to a 24 tooth attached to the rear tire. How will this perform, or should I use a different gear on the jack shaft? The 12, 52, and 24 are pretty permenant, cause I'm using the original 10 speed gearing the bike came with. But I'm just asking how one set up will act to give me an idea on how my bike will perform. Cause I am going to make mine shiftable using the shifter the bike has.
Wellp, Here it is!

Are you gonna connect this to shift thru the 10-speed cassette hub?

If so, it MIGHT be very difficult to get the proper gear ratios. Ya MIGHT be able to shift once or twice with the lowest gears.

Unsure also if your 10-speed chain can handle the engine's torque.

So 12t and 24t is permanent, huh?

12t connected to 39t jackshaft, then 52 jackshaft sprocket chained to 24t rear?

(39/12) x (24/52) = 1.5 gear ratio.

Your clutch will burn out, and the engine will not move the bicycle.

Here's an idea:

Using the frame's bottom bracket, connect the 12t clutch to the 52t sprocket = 4.333:1

Install a 12t chainring sprocket 0n the "pedal" side.

Keep your rear cassette.

Gear ratios will be EXCELLENT.

1st(24t) = 8.67:1.....
2nd is ?
3rd is ?
4th is ?

Your tires and rims look weak. Are these 70cc? You need stronger rims and tires.

More than likely, the engine's power will tear up the thin chain. If that happens, lose all the cassette gears except one. Change the cassette hub to a single speed system. Experiment by trying the 24t, then the 21t, then the 19t and so on. Then you can use a #35 or stronger chain.

The bike will be too fast for your brakes and existing tires/rims.

37mph and excellent acceleration at 4,000rpm, with the 52t/12t and 24t/12t sprockets.

 

[AnvilBlockForge]

Here's an idea:

Using the frame's bottom bracket, connect the 12t clutch to the 52t sprocket = 4.333:1

Install a 12t chainring sprocket 0n the "pedal" side.

Keep your rear cassette.

Gear ratios will be EXCELLENT.

1st(24t) = 8.67:1.....
2nd is ?
3rd is ?
4th is ?

Your tires and rims look weak. Are these 70cc? You need stronger rims and tires.

More than likely, the engine's power will tear up the thin chain. If that happens, lose all the cassette gears except one. Change the cassette hub to a single speed system. Experiment by trying the 24t, then the 21t, then the 19t and so on. Then you can use a #35 or stronger chain.

The bike will be too fast for your brakes and existing tires/rims.

37mph and excellent acceleration at 4,000rpm, with the 52t/12t and 24t/12t sprockets.

Yea, that's the idea. I'ma use the rear cassette to shift. And make a suicide shifter, Gotta have the "8 Ball" knob too xD. But that's the idea.
So run the 12t clutch to a 54t jackshaft and have a 12t run to the rear cassette?

And I do plan to get a new chain. I found a heavy duty chain made for Motorized bikes at www.kingsmotorbikes.com, says it's a #415 Heavy Duty Chain. Will that work? And I'm in the process of getting disc brakes.
My tires and rims will need to be replaced?

 

[AnvilBlockForge]

Floor boards redo

Cut the old floor boards off and put new ones n. I didn't like the old ones, lets face it, there were ugly xP So I used the plywood idea in Curtis's first link. Looks good! Later I'll stain 'em and put some polyurethane on em for strength and take the old floor mat in my truck and cut out some rubber grip for 'em!

 

[AnvilBlockForge]

1st(24t) = 8.67:1.....
2nd is ?
3rd is ?
4th is ?

Hahaha, didn't notice the "?"'s. Hahaha
I don't know if first should be the bigger gear, or smaller. Once again, I'm new to gear ratios. But this is their order from smallest to largest.
15, 18, 20, 24, 28.
So what will give me the most torque and speed? Cause don't I want torque to pull from a stop, then speed after I get moving?

And thanks for all your help! Your saving me from alot of headaches, and mistakes I'll have to fix later

 

[professor]

V brakes will be fine, always wear safety gear- helmet, vest and gloves.

When you LOOK safe and ride carefully- the police see someone who is responsible and generally leave him alone.

Consider all car drivers to be drunk any time you are on a bike of any kind.
Especially watch for them passing you by from behind and then turning right in your path after they pass you.

Good brakes are more important than any thing on the bike! Guys here have powered bikes with a coaster brake- a disaster waiting to happen. You are going to be going to be going 3 to 4 times faster than the typical cruiser bicycle rider.

I think my overall ratio on my 212 HF bike (9 hp) is 11 to one or so, this gives a top speed of about 35 mph (this is FLYING on a bicycle and I rarely do that, and not for long). But that engine has lots of torque, with i/3 the power, your clutch will be slipping a lot to get going. You really need pedaling to get going with a ratio in that zone.

I like having pedals. If something bad happens to the motor drive- I can pedal home. Think about walking your bike for several miles. When you could be riding it.

 

[AnvilBlockForge]

Saddle bags mounted

I'm using ammo cans as Saddle bags. Only one is mounted in the picture thou, still reinforcing it (it wobbles) so I'm gonna wait till I perfect it till I mount the other. But heres the pictures of what it looks like!

 

[AnvilBlockForge]

Consider all car drivers to be drunk any time you are on a bike of any kind.
Especially watch for them passing you by from behind and then turning right in your path after they pass you.

Good brakes are more important than any thing on the bike! Guys here have powered bikes with a coaster brake- a disaster waiting to happen. You are going to be going to be going 3 to 4 times faster than the typical cruiser bicycle rider.

I think my overall ratio on my 212 HF bike (9 hp) is 11 to one or so, this gives a top speed of about 35 mph (this is FLYING on a bicycle and I rarely do that, and not for long). But that engine has lots of torque, with i/3 the power, your clutch will be slipping a lot to get going. You really need pedaling to get going with a ratio in that zone.

Yes, safety is very important to me. I drive motorcycles, so I have a full face helmet, motorcycle boots, and a leather riding jacket. And I don't intend to go fast, I just like the option xD
Thanks for all the tips! People seem to ignore motorcycles, which is how most wrecks occur, so I highly doubt they'll notice a motorized Bicycle. So I'll keep all that in mind. And the pedals are long gone...

 

[5-7HEAVEN]

Yea, that's the idea. I'ma use the rear cassette to shift. And make a suicide shifter, Gotta have the "8 Ball" knob too xD. But that's the idea.
So run the 12t clutch to a 54t jackshaft and have a 12t run to the rear cassette?

And I do plan to get a new chain. I found a heavy duty chain made for Motorized bikes at www.kingsmotorbikes.com, says it's a #415 Heavy Duty Chain. Will that work? And I'm in the process of getting disc brakes.
My tires and rims will need to be replaced?

Yes, 12t to 54t, then 12t to rear cassette.

Sadly, the multi-speed cassettes use thin chains, because of how closely the sprockets are. #415 chain prolly won't work.

The best cassette shifter is the one on the handlebar.

Maybe you can use the 8-ball shifter for the brake.

Yes, heavy duty double-walled rims.