GY6 engine Swap

Difference in rear drum brake size - 110mm vs 130 mm on a 12 to 13 inch wheel.

"I got a 1p57qmj long case gy6 150cc with the rear drum brake setup, I need to get a 12" or 13" rear rim for it, but what are the drum dimensions and drum depth I need for the rim? I know my short case I side drum diameter is 110mm but I'm not sure about my longcase. I tried using my 139qmb rear rim but drum hub diameter was just a touch to small." - JT Boatwright

"Iv'e got this wheel off a 150 long case . It's 13 inch . The drum inside diameter is 130mm and the depth is 30mm . Give or take a mill ? I only had an old faded Chinese made plastic ruler." - B. Bamforth

130 mm drum size on 13 inch wheel with splines for GY6 150cc.

Here is the build JT did. Looks good. Here the 150 cc is in place, looks like he got a 12 inch wheel, kymco Style. Fits nicely.

Comparing the short case 50cc with a long case 150. Bottom mount vs Top mount.

The new 150cc with top mounts are welded into place.

Thanks JT and Bamforth for the pictures!