40mm cylinder or 44mm cylinder for my 49cc bike motor

[SanTanfan]

Hello all. I am new to the craft, and these articles/posts have really been helpful. This is my first build using a cheap Chinese motor kit. When I finally got everything running well, my cylinder locked up. Turns out the cylinder rings broke apart and destroyed the bore and cylinder. Now I know I can just replace the 38mm cylinder and bore easily, however, I was wondering if this would be a good time to try to upgrade to a 44mm big bore kit.? Are there any issues that I should be on the lookout for? I figure as long as the parts fit there should be no problems, any thoughts?

 

[Chainlube]

There are a few determining factors to consider, rod length, piston hole height and stud spacing. Measure everything carefully before ordering. If you sit the piston on a flat surface and measure to the top of the wrist pin hole then that will tell if you have a high or low hole piston. High hole piston fits the longer rod.

 

[Chainlube]

After looking around at some sellers, looks like the 49cc only has one rod length.

 

[SanTanfan]

how do I know if i have a long rod or short?

 

[SanTanfan]

I found this which has every measurement correct, but now I am questioning if the piston will fit the rod.
This is what I found.

 

[Mossy]

how do I know if i have a long rod or short?

Take a picture of it... Measure your piston from the top to the hole

 

[SanTanfan]

so From the top of the hole to the top of the piston?
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[Mossy]

From 2011 might help shed some light

 

[Mossy]

View attachment 174238
so From the top of the hole to the top of the piston?
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Looks like a low hole

 

[SanTanfan]

Ok so I need a low hole piston. so as long as I can get the rest of the measurements right I can still get a larger cylinder to replace the smaller stock one?