Dr 177 kit on px 125 E problems

Recently added a dr 177cc kit with 24mm del orto carb, 22 tooth cosa 2 clutch, sip road 2 exhaust, the kit came with 3 main jets, 120, 125 and 128. Not sure which one to put in. I have the 120 in it at the minute. It ticks over 100% but when I take it out for a test run it suddenly cuts out after going up through the gears. I can feel it starting to bog down after a while and then it just dies suddenly.

Anyone got any ideas on what set up I should be using? Also going to be adding a new sip curley exhaust very soon so any input for the correct setup will be much appreciated. I have also got the kytronik spark magnifier and sip digital speedo installed but I can see this having an effect.







from everything i've read the DR kit isn't a very aggressive kit. i would try a smaller jet, listen for pinging and check your plug. boggy usually means your too rich.