Modern Vespa

Recently fitted a dr177 to my 2004 px. Just bolt on pnp. Because I'm running it in at low revs and low speed at the moment it's running a bit rough. 1st and 2nd gear seem to hit a wall quite quickly.like a misfire. 3rd is ok then seems to 4 stroke when holding 30mph around town 4th gear does the same at 40mph and feels spluttery. My current jetting is 48/140 idle. 140/be3/110 on a 20/20 carb . Sip road 2 exhaust and standard air filter. Just wondering if this is kind of normal while the kit is running in and will improve with time and miles or if I need to change the jetting somewhere. Ridden 175 km so far.
Any suggestions greatly appreciated.

Have you reached out to the shop that sold it to you? What was their recommendation?

Kit was ordered from sip. I know they give recommendations using 24/24 carb. I plan to keep the 20/20 I have . Pretty sure that main jet isn't really getting used that much at low throttle opening so thinking my idle jet maybe a bit off . Not sure 🤷‍♂️

The thing that stands out for me is the BE3 atomizer. I think that is too lean, which can cause the motor to bog at about 1/4-1/3 throttle as the idle jet hands off to the main stack. I would go back to the BE5.

Otherwise, and as already discussed, I think the AC140/MJ110 combo will end up too rich, but should be ok for running in.

The 48/140 idle jet should be fine.

Ok thanks . Will stick the be5 back in and give it a go. I'm guessing the kit will feel better as more miles are put on it and the rings bed in ?

You would have to have the world's most discerning butt dyno to feel that difference. Just run it in to the point you are comfortable operating at sustained wide open throttle. Then you will you be able to finalize your jetting. That will make it feel better.