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!
 

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Foot rests welded on

Reinforced the frame a little and welded the Foot rests on. I still need to grind the welds clean. You can see where the welding made the paint come off, but I'm gonna end up repainting the whole bike once assembled. All of these mods are made from scrap metal xP
 

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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!

I admire your enthusiasm, young man!

Lemme see if I got this right:

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.

If you chain the 12t to the 52t sprocket, you get 4.333:1.

Then connect the 18t jackshaft to the rear 24t sprocket - 1.333:1.

4.333 x 1.333 = 5.78:1.

Then your bike will run VERY well.
 
This looks like a nice build. Are you going to keep the pedals? motor asist bkies are supose to have pedals....law.........Curt
 
Wow, I had a bike that was almost the same back in 1990. I bought it brand new. So i wouldn't call it vintage. It's not old enough. Mine was also a mountain bike. Looks like this bike has had it's fair share of part changes though. More vintage looking than the new style of bicycle though. Doesn't matter much i guess. I'm with curtisfox on this one. You should really keep the pedals. A call to Sick Bike Parts will get you the freewheel, crank arms, crank shaft, and sprockets you will need to keep your pedals. There are other companies that carry them too. Besides being the law. It's always good to have them if the engine breaks down in the middle of no where. You can always pedal your way back home.
 
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Mopeds have pedals? You are lucky I think every other state has to have them. Thats going to be a nice bike,I like how you did the frame to make room for the engine...........Curt
 
In Georgia the law allows me to have the pedals off. It's legally a moped here, so I don't need a licence or registration.
I don't believe however that you can have anything higher than a two speed transmission. and i believe it has to be automatic.I could be wrong on this laws for MB's are changing constantly. I also believe it is called a motor driven cycle not a moped. Mopeds fall under motor driven cycles. An old Honda Express i had fell under motor driven cycle. No pedals, front mounted footpegs. My old Honda PA50 fell under motor driven cycle, it had pedals. Had a Puch Maxi Sport. Had pedals. Fell under the same class as anything else. Better rip off the 3.5 HP sticker as well. I also believe the engine can not have horsepower any greater than 2.
 
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