Problems with performance after 80cc bbk install

[sxottyk69]

I've recently installed a 80cc bbk on my 50cc gy6,and now am having issues I can't seem to figure out the scooter will start off great when cold,run good,plenty of speed,and then suddenly it will start to kind of hiccup,pull back a little,then want to surge forward a little this doesn't stop unless I get off of it,let it sit for an hour,and then start again.i have a 35 mm pilot jet and 95 main jet.it has an aftermarket exhaust,with 3 13 gram roller weights,and 3 5 gram roller weights in the variator.im at my wits end,so.eone please help thanks in advance.

[GrumpyUnk]

The explanation makes me wonder if it is running out of fuel. That can be caused by a petcock, clogged fuel line, clogged filter, or sticky needle valve/float.
Also see if you have crud in the fuel tank that is getting pulled to the outlet tube and slowing the flow. Grass, leaves, etc can slosh around and get moved to the outlet by fuel movement, and as it gathers it can slow fuel flow.
tom