Motorized black mamba roadster project in Kenya

[remichi]

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/michisu...7629595539665/

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.

[thegnu]

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

[remichi]

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/michisu...57629595539665

http://www.flickr.com/photos/michisu...57629595539665

[chainmaker]

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.

[remichi]

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.

[cmanns]

Don't most prefer not riding with a tensioner ?

[remichi]

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.

[cmanns]

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

[remichi]

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.

[remichi]

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/michisu...n/photostream/

http://www.flickr.com/photos/michisu...n/photostream/

http://www.flickr.com/photos/michisu...n/photostream/