How to build a transportable motorized bike?

[Ferro]

Hi, I just registered here because I see that there are plenty of experience with little motors to apply on a bike. First of all excuse me for my english, i'm from italy and it's not my language.

Me and my gf would like to travel accross the Black Sea next year with foldable bikes, which fit well in a large backpack. We're thinking about motorizing those bikes.

We have to do some 2000-3000km so we need reliable motors, but I don't know much about this and that's why I ask you.
I thought about a chainsaw 50cc motor, simple to mount on the rear tyre, and transportable as well. Do you think it will last for 3000km?
We're goin to stay on the bike for 4-5 or maybe 6 hours a day, I don't know if this type of engine can afford this long operational time.
A classic 50cc bycicle oriented engine how long will last?
We're just planning next summer holidays, so if it's not worth we'll go by motorbike but the idea of taking the airplane and then have a motorized bike there is more fascinating me

I also saw the Revopower kit, anyone has tested it?

[deacon]

I have just started to work on chainsaws for bikes so I can't tell you much about the longevity. I am working with a 33cc chainsaw at the moment and have a 42 on the way now. I have no idea what a folding bike will do with one and never even heard of the kit.

What is the lay of the land there. Is it flat or hilly and how fast do you want to travel.

[Ferro]

we are planning to go to flat land, it's on a lake so there are many beaches and plains.

do you know any very light engine that can burst you to 30-35 mph?
i saw on ebay some chinese 80cc engine but it says that it goes no more than 20mph

revopower is a kit that will fit in the front wheel and it's very compact

[deacon]

Im the wrong man to ask to be honest. My bikes are designed to run about twenty or so. I frankly do not feel safe on a bicycle going thirty miles an hour. I have had my china kit up to 28 but was way to unstable for my taste. Possibly if you have big tires on it and the bike itself has a heavy frame it would feel stable enough but I am not sure about that. Some of the others here are more into speed.

If the ground is flat, you won't really need that much engine frankly. Since bicycled travel the world under people power, I would think the traffic passing you in Europe wouldn't be all that scary.

Why not take a train there and rent a couple of scooters? That would seem to be the best thing for the power you seem to want. I'm sure you could rent a scooter for the price of building a bike that would do what you need.

[Ferro]

you must return the scooter in the place where you rented, and if you do 2000km it's a little impossible to do, especially if you rent a scooter in Bulgary and you end your journey in Ukraine or Russia.

we're looking for something that we can bear in our backpack, i'm something 200lb and the bike is 20lb, i tried about 25mph and i feel comfortable with that.

i'm searching for some engines on ebay but here in europe there's no such things, thanks to all the epa laws that we have (one of the most restricted of the world).
in east europe i think we can go without license, here in italy and the rest of west eu you would have needed a license for the motorbicycle.

[deacon]

The best thing I can think of is to ask around where they are more familiar with what is available there and what the restrictions are. Frankly over here I would say get a 25 to 31cc weed whacker and build a frame for the front wheel. That would be the easiest thing to do. But I don't have any idea about what is available or what the laws are there.

I believe that a 31cc two stroke engine running friction drive wide open on a flat stretch could reach 25 and maintain it, but I have no proof of that. I am pretty sure my 33cc chainsaw will do that. I live in an area full of small hills so I have never found a purely flat area to let mine out. A friction drive has to build to full speed. In other words it accelerates then it just keeps on slowly going up. By the time that happens here I am on another incline so I have no idea exactly what it will do.

I weight 210 lbs so the weight issue is about the same for us. You should go to the store and hold a 50cc chainsaw to see what the weight is. My 33cc is pretty heavy compared to the weed whacker. If they have weed whackers there it would be the way to go on the weight issue anyway. I wish I knew more about what is available there.

Do they have leaf blowers there... Those engines in the states are about the same as week eaters... Also the hedge trimmers have gasoline motors here sometimes.

[5-7HEAVEN]

I installed a Staton friction kit w/Subaru 1.6hp engine and 1.125" roller on my 20" Dahon. I weighed 190 lbs(about 87kg), and this engine was a good match. It was quiet, cheap on gas, no oil mixing, and top speed was about 27mph. However, the bike would no longer fold. Then I changed to Staton chain drive and Mitsubishi 2.2hp engine. The bike would now fold, but it would not fit into the bag.

If I were to travel like you, I would remove the engine kits from the bikes every time I needed to travel by train. It is very quick and easy to remove and reinstall the complete engine kit in less than 20 minutes.You may have problems trying to transport gasoline engines on airplanes, maybe even trains.

Use a 4-stroke Honda or Subaru engine, which can go for longer distance than 2-stroke. You might get 200 mpg(80km per liter) of petrol.

Install a large seat, because it will a bumpy ride with no front or sear suspension. Don't plan to go faster than 30mph(48 km/hr) in spurts, for safety reasons.

Good luck.

[comfortableshoes]

I'm not sure i"d want to go more than 25 mph on a folding bike... I had one I considered motorizing but... It seemed dangerous.

The Dahons though are a good quality folder. With the folding involved I'd do a front wheel install instead of a rear wheel- shorter amount of cable to tangle or break.

Considering the European EPA laws I'd got with a 4stroke kit as well, that's not even considering the longevity of the engine. The 4strokes will go longer and harder for a long period of time.

You might be able to figure out a way that you can get it folded if you do the design right...

Good luck on this, read the forum there's a ton of info on here to help you with your build.

Also take lots of pictures so that you can load them up so we all can see your adventure!!!

[deacon]

I was glad to see someone else answer this member since I have never even seen a folding bike.

[Ferro]

I have to thank you all for the replies

We have 2 Dahon model FLO, the mountain bike from Dahon, it fits quite well my huge backpack. We had a lot of luck buying them used from a shop failure auction, because we could not afford the price of new (too expensive bikes).
I think the best thing to do is like 5-7HEAVEN said, to remove the engine each time we take the train is the best thing, the fact is that we will travel a lot with train with bikes in the backpack, there is no problem at all with it.

The final aim to all this is to take the transiberian train next years and go biking on the Bajkal lake in Russia, but this is too far for now... It will be enought if we will have our bikes up & running for a tour of north italy in winter and next summer for the black sea, if we see that this project (bike+engine in backpack) it's affordable and most of all, feasible.
We have been in denmark, uk and france, but without the engine, only bike

I'll start searching for some 4stroke engine, I also thought that a 4s is better than 2s for long distances, but I didn't know many things about it. In east EU there are no laws about 2stroke engines, so i can go with it as i want.
I read a lot on this forum, it's helping me so much figuring out the feasiblity of the project.
I go search for more info and see if here there are some reseller of those 4str engines... it's quite hard to find one i guess
thanks for now!