Your carb can look clean but is it? The small passages within the carb body are what matters. You need to ensure that the inside of carb is as clean or cleaner than the outside. Fuel delivery is critically important and needs to be verified working BEFORE looking elsewhere.

 

You need a #45 low speed jet and probably a little bigger high speed too. Straight pipes are not really recommended as they don't have enough back pressure to keep the air/fuel charge from escaping during valve overlap. (both valves open during compression stroke)
At least add anti reversion cones in the pipes.