Rebuilding Chinese 2-stroke engine - photo tutorial

Porkchop said:

I am by no means a "PRO" or "EXPERT" on these little engines. Is there a proper procedure to breaking down and putting them back together? I'll do a seaarch and see if can find the post by Norm on this ! They are very simple though from my point of view.
Thanks !

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I'm not telling you to go to the other site.

Hi Paul

Can you give us some idea as where to go on the net to find the info on rebuilding these chinese motorised bicycle motors.

I understand that they may be a simple engine.
It's like any process of learning - once you've done something 3 or 4 times, it all becomes quite simple.

The first time you do something without instructions, you multiply the chances of something going wrong.

Many years ago i had very close association with military aerospace, particulary when the organisation i worked in was developing boron patches to prevent cracks spreading in fatigued areas on the Australian FA-18's.
We didn't do "ANYTHING" without instructions, even if we did it 100 times previously.
You didn't even breath or put water to your mouth without refering to the instructions.

Having said that, i find great comfort in the instructional process.

Fabian

1.97mm! jesus. a 2mm ring is gonna have extreeemly low tolerance to ring flutter. No wonder these things dont rev sky high safely.


Anyone know if this is the same on the 80cc motor since he measured the 50cc starfire? If so its time to machine a new ring land.

Porkchop said:

I don't know if this will help you at all, but it's a photo of my engine I took apart a month or so ago to replace all the hardwear with high strength. Sorry I didn't take more. The engines are pretty simple. Anyone with previous engine experiece should be able to do it with no problem. Not much to them. Dont be afraid to crack them open. Nothng will pop out or fall out of them unexpected. In the photo, you'll see the block halves just as it was when I opened them. Notice the cylinder and clutch plate in the plastic container to the left of the photo. I don't know much more than this. I did not remove the connection rod or anything other than what you see in this photo. If you want/need more info, let me know. I'll try to help.

..... PC .....

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Nice workbench lol lose any parts in the process? I know organized chaos!!

Fabian said:

G'day all

Can someone post a photo tutorial with hi-res pics, showing the complete strip down (all the way to rebuilding the crankshaft) and rebuild process of a Chinese 2-stoke motorised bicycle engine.

Fabian

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Step by step even a "Caveman" can do it.

I concur,and you're comparing apples to apples.

Can someone tell me if its cheaper to rebuild or just buy another motor? Figure the cost of an 66cc at 180-200 dollars.

rj1967 said:

Can someone tell me if its cheaper to rebuild or just buy another motor? Figure the cost of an 66cc at 180-200 dollars.

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It depends on your skill and available tools, like a bearing press.
Sure you can beat bearings in and out but really ill-advised if you an help it.

Gasbike has unassembled 66cc engines for $99 a couple years back, I bought a couple just for spare parts but built one up.
What a pain in the butt.

Here is what is involved (turn your sound off unless you are a Rocky fan).



That video leaves out some really import parts like keyways and seals but overall what is involved.

Ive seen some new engines for what you said about 100 dollars and I alteady have the other stuff like chain..sprocket. .clutch and so on. And I certainly dont have the know how or the tools. Guess that answers my question. Thanks.

if you live near someone that builds, then he should be able to hand you a new motor for $100