What size is this piston?

[bioboi]

The one on the right. Its definitely smaller and cannot find it anywhere came off a 100 dollar kit from ebay. Can someone tell me the size or link me to a site where I can buy it with piston rings and clips?

 

[Bikeguy Joe]

Measure it across the widest point. It could be from an engine anywhere from 45cc to maybe 49cc.
I've built kits in the range from 45 to 68cc's.

 

[bioboi]

I updated the pic,
What im measuring across the top is 25 mm

 

[bioboi]

Measure it across the widest point. It could be from an engine anywhere from 45cc to maybe 49cc.
I've built kits in the range from 45 to 68cc's.

updated

 

[bioboi]

Please help!! I know the differences between model a and b it is a type a but this piston is all around smaller
width is 25mm length is 30mm it has a rounded top

 

[Bikeguy Joe]

Check with the various vendors, and see if they have you size.

 

[Larry Trotter]

I updated the pic,
What im measuring across the top is 25 mm

 

[Larry Trotter]

I don’t think it’s 25mm. 25mm is about an inch and yours looks like about an inch and a half.

 

[bioboi]

I don’t think it’s 25mm. 25mm is about an inch and yours looks like about an inch and a half.

I went out bought a ruler it says 38mm it this correct? just got my stimulus money yesterday and bought an engine but i still want to fix this one for backup!

 

[bioboi]

I don’t think it’s 25mm. 25mm is about an inch and yours looks like about an inch and a half.

I went out bought a ruler it says 38mm it this correct? just got my stimulus money yesterday and bought an engine but i still want to fix this one for backup!

 

[Larry Trotter]

Not saying this will fit but think it’s likely. For $30 not too much risk.
https://www.ebay.com/itm/Cylinder-H...rand=Unbranded&_trksid=p2332490.c100935.m2460

 

[bioboi]

Not saying this will fit but think it’s likely. For $30 not too much risk.
https://www.ebay.com/itm/Cylinder-Head-Piston-Kit-For-Regular-49cc-50cc-Motorized-Bike-High-Quality-New/123712984506?_trkparms=aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20190917065201&meid=a7eefde27de74b8784b72f280819c91c&pid=100935&rk=2&rkt=12&mehot=co&sd=283405046147&itm=123712984506&pmt=1&noa=0&pg=2332490&algv=SimplAMLv5PairwiseWeb&brand=Unbranded&_trksid=p2332490.c100935.m2460

just measured everything out it seems to be the right one! how did you find this one on ebay?
So I can go ahead and look some up myself?

 

[Bikeguy Joe]

I went out bought a ruler it says 38mm it this correct? just got my stimulus money yesterday and bought an engine but i still want to fix this one for backup!

That is 38mm.

 

[Larry Trotter]

It may be easier to replace both cylinder and piston if this set fits. There are many of these on eBay so look at a few.