Poor idling.

[Shingler4596]

From about 50°c up to about 80°c my cg13 runs a bit rough very shake and revs drop quite low. Also has a flat spot on when revving but only for a moment. Any idea what this would be? I've changed the plugs it's had a full service. Etc etc it has a fusion fabrications inlet and a pod filter. And a good flow exhaust. That's about all that's been done to it. Thanks