new 50mm bbk help

[tydye00]

i just installed a new 50mm big bore kit on my taotao 50cc, everything has been installed correctly, and it was all buttoned up and ready to go. my kickstart is broken, so i only use the electric start. when i went to go crank it, the starter has a difficult time cranking it over, and the green ground wire gets smoking hot. i took apart the entire wiring harness, and no wires are crossed and its clean. im stumped, would anyone know what the issue?

also, is the piston supposed to be moving smoothly? cause it feels like theres a lot of resistance in the piston and cylinder.

[tortoise2]

Jul 3, 2020 14:59:14 GMT -5 tydye00 said:

installed a new 50mm big bore kit

Vendor link?  Was a replacement head with a larger combustion chamber included?

[tydye00]

Jul 3, 2020 15:25:39 GMT -5 tortoise2 said:

Jul 3, 2020 14:59:14 GMT -5 tydye00 said:

installed a new 50mm big bore kit

Vendor link?  Was a replacement head with a larger combustion chamber included?

www.amazon.com/dp/B07YBZFD75/ref=cm_sw_r_cp_apa_i_qx5.EbW17JY6J

this is the big bore kit i ordered. just something from Amazon. came with the entire top end with new cam, head, piston and cylinder.

[tydye00]

the starter motor works, but does not have a ground cable coming out of it. is it supposed to? i picked this up as a junker and am rebuilding it. i didn't touch the wiring harness pre-install and it was working just fine. (other than the plastic connectors) only started doing this after the bbk was installed.

[tydye00]

so i actually figured it out myself, and i feel kinda dumb for it turns out it was just a bad ground! added a couple extra wires from the valve cover to the frame, and problem solved! it at least cranks better now, and i can crank for a bit longer, however i still cant crank it for too long without risking melting and overheating one of the ground wires (not the wire harness ground this time, so at least its replaceable without buying a whole new harness). still didnt technically get it running yet, but its a step in the right direction.

[Petro]

One's you brake the engine in the starter will work better, mine too has some hick ups sometimes. I like that though, shows me that the kit still holds compression and doesn't wear down fastly.

[mikehailwood]

I too had hot wires from my starter when my scooter was stock. I removed the starter motor and disassembled it for inspection. The starter motor bearings were very worn and dry, causing the motor to drag. It felt awful when turning the shaft by hand. A cheap new starter corrected this issue and it works fine with the 72cc bbk too.