Motorized black mamba roadster project in Kenya

Discussion in 'Motorized Bicycle General Discussion' started by remichi, Apr 23, 2012.

  1. remichi

    remichi New Member

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    Hi all,

    I'm a Dutchman living in Kenya since March and planning to start a motorized black mamba roadster project here. Last week I visited Gilgil, a small town to the west of Nairobi. There I came across boda boda bicycle taxis, and even many that engines in them! See my Kenyan Bicycles set on my Flickr page:

    http://www.flickr.com/photos/michisunited/sets/72157629595539665/

    Before last week I was already planning to buy a bicycle here, but since seeing the motorized version, that's the new aim.

    At the end of the week I'm going to the most western part of Kenya, Kisumu city. There are many bicycle taxis (boda boda) there and also motorized versions. In Nairobi I have not been able to find an engine yet. Hopefully I will be able to find one in Kisumu.

    Some of the motorized bicycle owners in Gilgil told me that the engines sold in the shops at the moment are not good though. Their engines are about 3 years old and much better. The problem I'm having is that none of the engines I come across have any make or brand on them. How am I supposed to know which engine is which??

    My questions to you guys, do you have any advice on what to look for in the engine. And can you advice me on some good makes?

    I will be updating the progress I make on the bicycle here. The plan is to get a head light, leather back seat, passenger foot rests, strengthened back passenger seat, mud guards etc.
     
  2. thegnu

    thegnu New Member

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    COOL pics , the 2 stroke motors are all just about the same from my experience ,which isnt very vast, the 4 strike motors are harder to choose from , but I am positive other members here could advise you better , as a general set of rules "complements of lrjerry" 1) What is the predominant riding terrain?
    2) What type of physique does the primary rider have?
    3) What will the rider's local laws allow and require them to have?
    (Lookup and personally read these laws.)
    4) What kind of bike is being motorized?
    5) What is the bike to be used for?
    6) How much of a budget is to be used for the build?

    Welcome to the forum
     
  3. remichi

    remichi New Member

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    I bought an engine today. Seems to be a Chinese make but had no box, manual and the name plate seems incorrect. It says that its a 100cm3 engine (YD47) which seems to be incorrect. Does anyone know engine with this number on it? The Chinese characters state: 中国广州三和助力车公司 "Zhongguo Guangzhou Sanhuo Zhuli Chegonsi". Can't find anything on them on interet though....
    On the rectangular fuel tank it says "Xiaobaitu cf50".

    I am missing the chain guard which I can hopefully pick up at the shop.

    Bought a second had oval shaped gas tank already. So hope to be installing it all this week.

    I don't like the exhaust pipe color, so might paint that with heat resistant black paint.

    http://www.flickr.com/photos/michisunited/7660958684/in/set-72157629595539665

    http://www.flickr.com/photos/michisunited/7660955062/in/set-72157629595539665
     
    #3 remichi, Jul 28, 2012
    Last edited: Jul 29, 2012
  4. chainmaker

    chainmaker New Member

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    Very cool bike! As for the motor...looks like any generic chinese 49 or 66 cc motor kit, seems like you have just about everything you need. Search the forum for chain tensioner solutions, those kit ones arent much good.
     
  5. remichi

    remichi New Member

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    What are the dangers of the standard chain tensioner? The fact that the chain can push it into the spokes I presume.

    Was thinking of welding a horizontal piece of metal to the bottom bicycle frame to which I will then mount the chain tensioner. This means the chain can be tensioned horizontally and vertically.

    I read here on the forum also a way without the tensioner, by tensioning the engine itself and inserting some t-shirt shaped washers, and cutting out chain links when the chain gets too long.

    I want to also still be able to use the bicycle without the engine, so I don't want too much drag from the second chain when the engine is off. Is the no tensioner then a good idea? Or get a better rolling tensioner like a mountain bike derailleur?

    Any advise on how to make a kind of vintage looking tensioner system is much appreciated.
     
  6. cmanns

    cmanns New Member

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    Don't most prefer not riding with a tensioner ?
     
  7. remichi

    remichi New Member

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    Does anyone know a link to a topic post about the no tensioner settings, preferable with pictures. Can't seem to really find much about it, besides seperate posts inside a topic.

    My bicycle has 28" rims and I just counted the teeth on the sprocket, it has has 48 teeth. Kenya has some hills so hopefully this setup is good enough to get up the hills.

    Will probably try the setup without the tensioner, if I'm able to find a stronger chain here in Kenya.
     
  8. cmanns

    cmanns New Member

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    Well it's up to your setup. I almost needed a tensioner with my over rear but I just wonked the chain tight. I do not believe it'll stretch enought o fling off, I hope it does stretch alittle like most say. Otherwise it's just a nice tight chain like I'd do on some bikes and such but the motor sprockets teeth clank the chain going in reverse.

    Try it out and see if you like it. I've read on here tensioner on the derailer side, which I took as those bikes which have adjustment on how the wheel is mounted so you can pull it back by screws or whatever. Use that to tighten engines chain, and use tensioner on the other but I don't see why it'd be needed on the other side >_>

    If where your motor sits, and chain sized fits alil snug, I've read here people say it should stretch alil and be fine, or need slight tensioning or pull back wheel.

    I read here for weeks, you don't really make progress reading and chatting. Test things out and ask questions. I just got mine going 2 days ago, if the tensioner less chain pops off or brakes I'll let ya know :)
     
  9. remichi

    remichi New Member

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    Well I have managed to screw up the carburettor already! The guy at the shop told me to be careful and I was, but still something went wrong..

    The manifold was too wide to fit into the carburettor and so I had to take some metal away with a veil. When carefully fitting it into the carburettor opening 3 of the 4 pieces of cast aluminium immediately broke of. Now only one is left and I'm never going to get the manifold tightly in place.

    The design and quality of this Chinese carburettor really is the worst! It would've been better if I could have bolted the manifold to the carburettor the same way the manifold bolts to the engine. Now I have to go and find a replacement carburettor here in Kenya which'll be a challenge to say the least.

    There are many Chinese 125cc motorcycles here, is there any way I can fit a motorcycle carburettor to my bicycle engine??

    Pictures of the damaged carburettor will follow later.
     
  10. remichi

    remichi New Member

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    Tried putting in the engine today and to my surprise the engine is too wide for the pedals!! I didn't measure this when I bought the engine....

    Starting to become a rather frustrating project.

    On the right side of the bike the pedals pass the engine fine, but the left side is wider and the pedals would need to be moved outward about 1 cm. I'm really starting to wonder how all those taxi bicycles in Gilgil got their engine working properly. Their engines are older and maybe have a different width.

    The chain does seem to line up nicely and even the chain tensioner is ok the way it is. My frame is oval so the chain tensioner will not move as quickly I hope.

    So things to be done are:
    - think of a solution to engine width/pedal clearance. The bolts sticking from the engine are not long enough for the engine to be put higher in the frame.
    - get a replacement carburettor. Once those parts are broken off, fixing seems impossible.
    - go back to the shop, to pick up the chain guard which they didn't give me.
    - find a way how to get the foot back brake they provided to work properly.

    http://www.flickr.com/photos/michisunited/7686028280/in/photostream/

    http://www.flickr.com/photos/michisunited/7686025570/in/photostream/

    http://www.flickr.com/photos/michisunited/7686032352/in/photostream/
     
  11. remichi

    remichi New Member

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    I think I fixed the carburetor. I took all the bad quality side pieces off that are supposed to clamp the manifold, then made it level with a file. Next I took a piece of tubing that fits the opening of the carburetor and cut just one side opening (instead of the 4 on the stock one).

    I welded some clamps that clamp around the side of the carburetor and all seems to be working well.

    With this system I definitely do need a gasket though between carburetor and manifold. What kind of material is best to use as a gasket between manifold and carburetor? According to my measurement it should be a ring of 18mm diameter. Hopefully I'll be able to find something in Kenya.

    Haven't thought of a solution for the engine being too wide...
     
  12. remichi

    remichi New Member

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    Went to the local bicycle repairman and worked on the engine today.

    Was hoping to drive home on it but had to pedal...the engine won't run yet.

    Have installed the back sprocket, cdi, carburetor, throttle handle, clutch handle etc.

    When putting on the chain I still had to press the clutch lever to get the drive sprocket to turn.

    Later in the process we tried to start the engine and nothing, also no spark as far as I could see. I then took off the drive gear cover and now when trying to put it back together the cover won't fit anymore. It seems that suddenly the bucking bar won't move in any further. There is a ball bearing but I can't seem to get that out.

    Have searched the forum for the solution but can't find it. First I have to get the drive gear cover back on, then I can go forward and try to start the engine again. I hope someone has the answer to my dilemma.

    With the drive gear cover off I was able to bicycle like usual and I drove the 7 km home just by pedaling.
     
  13. remichi

    remichi New Member

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    Just an update.

    The bike rides and I've ridden it for about 50km so far.

    Just want to post some pictures of the homemade carburetor solution I made. The stock NT carburetor is such bad design, the part that connects to the manifold anyways.

    Having no spare carburetors in Kenya and most sites not shipping to Africa meant I had to come up with a solution myself.

    I welded a clamp that clamps behind the carburetor and connects to the manifold. I put a rubber gasket in between to prevent any air from escaping. I also have a fiber gasket, but the black rubber one seems better. Anyone have any advise on what gasket to use? More people should be having problems with their carburetor/manifold connection I imagine. Some pics of my carburetor solution.

    http://www.flickr.com/photos/michisunited/7759542500/in/set-72157631018230298

    http://www.flickr.com/photos/michisunited/7759540912/in/set-72157631018230298

    http://www.flickr.com/photos/michisunited/7759539564/in/set-72157631018230298

    I put the needle ring to leaner, but still as soon as I disengage the engine it revs much higher than when it is engaged. Any ideas on this?

    Here's a photo of the finished bike in the sun.
    http://www.flickr.com/photos/michisunited/7746686080/in/set-72157629595539665

    What's left is the chain guard, and a better kill switch.
     
    #13 remichi, Aug 11, 2012
    Last edited: Aug 11, 2012
  14. Moto

    Moto Member

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    The high revving is from an air leak. I would recommend you look for a replacement carb and manifold were you got your kit or on an ebay listing that ships worldwide. Your bike looks great, good luck moto
     
    #14 Moto, Aug 11, 2012
    Last edited: Aug 11, 2012
  15. remichi

    remichi New Member

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    Made a copper fuel pipe from some refrigeration pipe. Will try and make one with more loops but this one looks nice.

    Also made a new air filter from a soda can, so far it seems to run a lot better. Put a strip of the soda can between the manifold and the carb and the air leak also seems to be gone.

    [​IMG]

    [​IMG]
     
  16. silverbear

    silverbear The Boy Who Never Grew Up

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    Welcome to the forum. I see that you are resourceful and don't give up easily. That's good! Your bike looks good and I'm glad to hear you're riding it. What did you do to solve the pedal running into the engine problem? I was going to suggest bending the pedal arm in a vice as I have needed to do that on several bikes. I like your rear drop stand.
    What kind of reaction are you getting from the local people... is there much interest?
    SB
     
  17. remichi

    remichi New Member

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    The pedals were just bent with brute force with the help of the local bikeshop. Wasn't my favorite way to do it, but it worked.

    People are really interested in the bike and can't stop asking questions. People mostly use motorcycles these days so seeing a motorized motorcycle is quite special.
     

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