Discussion in 'Photos & Bicycle Builds' started by AnvilBlockForge, Mar 16, 2012.

  1. 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!

    Attached Files:

  2. You think a cop will know it's not a 49cc?? Hahaha
  3. 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

    Attached Files:

  4. 5-7HEAVEN

    5-7HEAVEN Active Member

    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.
  5. Ok, so I need to just flip the jackshaft over. Ok! Thanks! How fast do you think this will get me going? I only weigh 106lbs xD
  6. curtisfox

    curtisfox Member

    This looks like a nice build. Are you going to keep the pedals? motor asist bkies are supose to have
  7. Neon

    Neon Member

    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.
    Last edited: Mar 21, 2012
  8. 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.
  9. curtisfox

    curtisfox Member

    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
  10. Neon

    Neon Member

    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.
  11. I read the Georgia laws. And in Georgia it says a Moped is any 2 wheel vehicle with a motor under 50cc and not REQUIRING shifting with a clutch. Mopeds don't require a motorcycle's licence or registration and insurance. I don't have a clutch and shifting isn't required, so I think I can pull strings if I get pulled over. Motor assisted vehicles in my state I believe falls into Mopeds. Correct me if I'm wrong, but that's what the Georgia laws say. And I do plan to take the sticker off xD
  12. Neon

    Neon Member

    Ok, just trying to save you from a very expensive time. I don't want anyone to go through what i did. Not saying you will, but it could still happen. Actually it looks like your laws are very relaxed. Here i guess anything a person does is never completely legal.
  13. Yea, haha, I don't think there are any laws here in Georgia specific on motorized bikes. But I've seen them get more popular so only a matter of time before they see it as something to control and make money off of...
  14. How will it run? How will it accelerate and how fast will it go? I'm kinda new to gear ratios
  15. 5-7HEAVEN

    5-7HEAVEN Active Member

    Fast enough to fear for your safety. It's not the best gear ratio; it is a VERY good ratio, using the sprockets you have.

    Install a used suspension fork with disc brake, please.
    Last edited: Mar 21, 2012
  16. 5-7HEAVEN

    5-7HEAVEN Active Member
  17. I've been thinking about front suspension, seems difficult, but possible. I like the old leaf spring suspension like on old Harley's, but don't know how they work exactly. A little research would allow me to fab one up thou. And disc brakes are on my to do list xP But will mountain bike disc brakes work, or should I take em off a small motorcycle and attach it somehow?
  18. 5-7HEAVEN

    5-7HEAVEN Active Member

    It's pretty easy to install a suspension fork w/disc brakes. Remove handlebar, stem and nuts, and everything falls out.

    Measure the shaft, its width and length. If it's 1 1/8", most generic or aftermarket suspension forks w/disc brake brackets should slip right in. If yours is threaded and the replacement is threaded w/same length, everything should bolt right in.

    If your shaft is 1", ya might have to buy a new fork. Suntour has 1" forks on ebay for less than $100.

    Just make sure you have front and rear brakes.
  19. Yes, I am going to have the front brake ran to the left handle and the rear brakes on a pedal under the right foot, like a motorcycle. But what happens if the brakes lock up? Won't I go over the handle bars?

    And I've been drawing up plans for front suspension. I don't have the budjet to buy a new fork, so I'll upload pics of my drawing tomorrow when I'm finished working it out to see what ya'll think. I blacksmith so I will probably forge up Leaf spring suspension.
  20. 5-7HEAVEN

    5-7HEAVEN Active Member

    Keep both brakes maintained, and NEVER lock up the front brakes alone.

    With that heavy engine, that should make it less likely to end-over the bike, I would think.