Difference Between 49, 61, & 66cc Jiangdu Engines

[UVsaturated]

Copied from manufacturers site:

Notes:
1. As for the 80cc, in fact there is no such cc bicycle engine in china market, we called our 47*38(bore*stroke) engine F80 before ,but now we correct it, because its displacement is only 66cc(from EPA test report).
2. How to caculate the engine capacity. The fomula is listed below.
The volume of a cylinder=(bore area)x stroke
Bore area= Bore x Bore x pi / 4. (pi has a value of 3.14159)
Take our ZM70-P for example, its bore is 4.7cm(47mm), its stroke 3.8cm(38mm)
4.7×4.7÷4×3.14×3.8=66cc

I hope this is helpful to some of you. I was sent the entirely wrong engine from an online supplier of kits. I went ahead and installed the kit and it works fine, but while trying to inspect the internals I broke a ring and without any documentation that came with it, I was out of luck trying to ID the displacement. I ordered a set thinking it was the 49cc model, but instead found out that it is the 66cc version.

Is there any markings on the blocks of these engines that says what make they are?

 

[rohmell]

No markings on the block, it is the top end that determines the cc of the engine.(cylinder, piston and head)
All bottom ends are the same.

 

[gera229]

Specifications from China are not accurate. The cc may or may not be correct, but the horsepower ratings are incorrect. These engines (66cc model) are most definitely under 2.5 horsepower maximum with a modified exhaust/ expansion chamber I believe.

 

[UVsaturated]

Specifications from China are not accurate. The cc may or may not be correct, but the horsepower ratings are incorrect. These engines (66cc model) are most definitely under 2.5 horsepower maximum with a modified exhaust/ expansion chamber I believe.

You're right, I also found an updated version of this table that showed the compression being 8:1. I'm not sure if these guys can't comprehend math or not, because they obviously can manufacture an engine, but I can't see how their numbers would be so off between two different tables.

It also lists that the engine I have has a max speed of around 38kmh, which is not true. The bike will do a lot faster than this. I guess in China you just have to get it in the ballpark.

Once I get the bike back on the road again, I am going to blueprint it and redesign it to my own standards and get into manufacturing an Americanized likeness of it with an electronic fuel injection and variable ignition timing. The reason I bought it was to use it as a test-bed of sorts.

 

[biknut]

I think generally, but not always, 50s have M6 cylinder studs, and 80s have M8 studs.

 

[UVsaturated]

I'm not sure, the kit I bought didn't come with a lot of documentation of what it was, and it was even the wrong engine. I ordered a 4-stroke kit, but they sent me the 2-stroke - decided to install it anyway. It was like a grab bag, you just get whatever the company sent ya.

But mine definitely has M8 studs for the cylinder and it has a 47mm bore. The studs for mounting it to the frame were very inadequate. They are M6. I tried mounting the block to the frame with rubber but the engine would shift causing alignment problems with the chain, so I removed the rubber but the vibration caused the nuts to vibrate loose. I removed all the M6 mounting studs from the block and re-drilled and tapped them for 5/16-18" which is much more rigid. I bought a piece of threaded rod and made 5/16" studs from that and used nylon locking nuts which works way better than the lock-washers the Chinese were using.

 

[biknut]

But mine definitely has M8 studs for the cylinder and it has a 47mm bore. The studs for mounting it to the frame were very inadequate. They are M6. I tried mounting the block to the frame with rubber but the engine would shift causing alignment problems with the chain, so I removed the rubber but the vibration caused the nuts to vibrate loose. I removed all the M6 mounting studs from the block and re-drilled and tapped them for 5/16-18" which is much more rigid. I bought a piece of threaded rod and made 5/16" studs from that and used nylon locking nuts which works way better than the lock-washers the Chinese were using.

The 80 engines have 47mm bores

 

[UVsaturated]

The 80 engines have 47mm bores

Yes, then they must also have a longer stroke of the crankshaft.

 

[biknut]

Yes, then they must also have a longer stroke of the crankshaft.

I don't think so. The 50s are smaller bore. They use different head and base gaskets.

 

[UVsaturated]

It's hard to tell, like I said I didn't get any documentation of the engine size when my kit came in the mail, so it tells you the distributors are just buying them in lots of 100 or so, at half the cost. Yes, they cost around $70 USD straight from China. I bet the heads are mismatched or whatever this company had lying around. It's a strong little motor, but you have to have some mechanical inclination to want to use it on your bike. What I want to do is 'Americanize' the design so it works really good right out of the box and would be manufactured here in the states, with a good cheap supply of parts that can compete with foreign markets. What do ya think?

 

[biknut]

I like your idea. I think the first place to start is the crankshaft. I'm studying 3 of them right now. They're all very poor quality. Of the 3 I have only one is close to true. 6flywheels, 6 different sizes. The crankpin is hollow, and weak. I can flex the flywheels with my fingers.

 

[gubba]

UV

give us the direct to buying from china..... andshipping costs? thanks

gubba

 

[gera229]

Shipping costs by air male are around $120 maybe higher for just 1 engine kit.

 

[gubba]

i was asking UV for an address/source in china direct per his post.......
your reply did not come close to the answer.

gubba

 

[gera229]

You asked for shipping cost and I gave you an approximate. I have bought many products from China and even requested for engine kits from many suppliers there so I would know.

But that is shipping by airline. Shipping by cargo is cheaper, but takes much longer to arrive.

 

[donb4103]

You can go to alibaba.com and see for yourself what the retailers are paying for these kits. I am a member there but I can`t afford to buy 100 or more at one time. That`s what the manufacturers want you to do.

 

[mapbike]

You can go to alibaba.com and see for yourself what the retailers are paying for these kits. I am a member there but I can`t afford to buy 100 or more at one time. That`s what the manufacturers want you to do.

Yep your dead on here, I've looked there myself....

 

[gera229]

Be careful with Alibaba, some can be a scam. You should know who you are dealing with.

 

[UVsaturated]

UV

give us the direct to buying from china..... andshipping costs? thanks

gubba

JIANGDU FLYING HORSE GASOLINE ENGINE FACTORY
some bicycle engine and disposition, 4-stroke bicycle engine, 2-stroke bicycle engine direct from
China Bicyle Engine Manufacturer - Jiangdu Flying Horse Gasline Engine Factory

You would have to look around. You can't just buy one unit direct from China, as far as I know. This comes from B2B (business to business) directories where you buy them in lots of lets say for example 100 engines. They usually will list on these sites the minimum order, but the prices are way cheaper. I forget the exact site, but the price was $70USD for one of these kits from China. Note, you will probably have to pay a fee for a brokerage firm to handle the shipping, which will cover import taxes, brokerage fees, insurance, and shipping. That may only get your crate of engines to a major port, then you would be responsible for shipping to your local city.

That's for someone who wants to sell these like some of the others are doing. You have to have some coin to do this.