Considering a 47mm 72cc kit. Reliability?

[thekisbeeman]

As the title says, I'm thinking about getting a 47mm 72cc kit for my 2016 Peugeot Kisbee. I'm just wondering about how reliable and how long lasting it would be and what extra parts you would recommend.

Thanks in advance!

[GrumpyUnk]

there is a section on site regarding different sized BBKs, how they last, etc. Seems the 72cc is a good match for reliability and output. The 60cc kits are often overlooked, but they also give a good boost, with likey a bit more life & reliability than the 72cc kits. You can do the install and not much more and get decent response. You may want to tune the jets or get a larger diameter carburetor, but they are not absolutely necessary.
I have tried from Dariver and aliexpress with decent results. Personally I like the fiber head gasket with the metal 'fire ring' that faces the combustion. Seems to me the stamped steel gaskets are thinner and will give a bit higher compression ratio, and they also like very flat and smooth surfaces to seal properly. The fiber gaskets allow a bit more non-uniformity of the surfaces and still seal well.
tom

[thekisbeeman]

Apr 24, 2023 16:23:52 GMT -5 GrumpyUnk said:

there is a section on site regarding different sized BBKs, how they last, etc. Seems the 72cc is a good match for reliability and output. The 60cc kits are often overlooked, but they also give a good boost, with likey a bit more life & reliability than the 72cc kits. You can do the install and not much more and get decent response. You may want to tune the jets or get a larger diameter carburetor, but they are not absolutely necessary.
I have tried from Dariver and aliexpress with decent results. Personally I like the fiber head gasket with the metal 'fire ring' that faces the combustion. Seems to me the stamped steel gaskets are thinner and will give a bit higher compression ratio, and they also like very flat and smooth surfaces to seal properly. The fiber gaskets allow a bit more non-uniformity of the surfaces and still seal well.
tom

What about how long the crankshaft will last, I've heard that even with the 72cc the crankshaft is prone to failure after short bit of usage. Do I need to replace the crank or will the stock one do for a few riding seasons.

[GrumpyUnk]

O cannot state for a fact, but highly suspect that 98% of all BBK installations keep the original crankshaft. I think(no proof) that the 49cc version is made to conform to USA state laws regarding low powered scooters, their operation, and who is allowed to operate them. In some states, 49cc is the max allowed for non-licensed, non-insured operation, with/without a motorcycle endorsement.
Given that, my take is that the crankshafts used are all the same in the original countries where the scooters are the main form of transport. If you have not, you should view a YT video on some countries where the whole family, dad, mom, kids and the things they are taking to market are all piled onto a scooter. In those areas, it is common to remove the cylinder, piston and rings, hone the cylinder to a .05mm larger diameter or whatever it takes to clean up, and fit new piston & rings. They do not throw away worn cylinders. So, makes me think the crankshafts are more indestructable than is thought in USA. But, they need good oil and some sort of limit to the rpms they are forced to endure. If you don't beat them too severly, they will last is the long & short.
tom

[thekisbeeman]

Apr 25, 2023 8:53:21 GMT -5 GrumpyUnk said:

O cannot state for a fact, but highly suspect that 98% of all BBK installations keep the original crankshaft. I think(no proof) that the 49cc version is made to conform to USA state laws regarding low powered scooters, their operation, and who is allowed to operate them. In some states, 49cc is the max allowed for non-licensed, non-insured operation, with/without a motorcycle endorsement.
Given that, my take is that the crankshafts used are all the same in the original countries where the scooters are the main form of transport. If you have not, you should view a YT video on some countries where the whole family, dad, mom, kids and the things they are taking to market are all piled onto a scooter. In those areas, it is common to remove the cylinder, piston and rings, hone the cylinder to a .05mm larger diameter or whatever it takes to clean up, and fit new piston & rings. They do not throw away worn cylinders. So, makes me think the crankshafts are more indestructable than is thought in USA. But, they need good oil and some sort of limit to the rpms they are forced to endure. If you don't beat them too severly, they will last is the long & short.
tom

Thanks for the info man, will post some more when I'm getting the 72cc installed.

[frankenscootdk]

Can i ask what fiber head gasket you meant?

[GrumpyUnk]

There are two styles I am aware of. Stamped sheet of steel, with nothing besides metal used to make the gasket. Requires, IMO, a very finely finished surface on the head and cylinder to seal properly.
Fiber with metal fire ring and sealant patterened onto the fiber(red, generally). The fiber type have a steel ring crimped onto the i.d. of the gasket where it will seal the head and cylinder. The ring protects the fiber from directly touching combusting hot gases. The fiber will allow for small imperfections in the surface and likely still seal well. I think as it is thicker than the stamped steel, it will lower the CR slightly.


Those shown on this page:
www.aliexpress.us/item/2251832667836908.html?spm=a2g0o.order_list.order_list_main.35.1f811802tC37xB&gatewayAdapt=glo2usa4itemAdapt
The color is different from previous ones I have used.
tom

[frankenscoot]

Nice. Thank you.

Had only seen them for 2t. Useful to know.

[muhovic]

May 8, 2023 6:50:11 GMT -5 frankenscoot said:

Nice. Thank you.

Had only seen them for 2t. Useful to know.

Is your peugeot fuel injected?
If it is how did you put a big bore kit because and how did you get more fuel?