Modern Vespa

Hello all, I've got a 78' P125X. I've been having some issues with it dropping speed when going uphill. I've read on some other topics that this issue can be solved with new exhaust and new jets in the carb. I've ordered a SIP Road 3.0 exhaust (only got the 3.0 because it was on sale for same price as 2.0). I'm curious if it is necessary to change the jets?

I've got a Dellorto SI-20/20 D carb. I'm not too knowledgeable on the jet information. I will list what is etched on each jet. My main jet has 96 on the bottom portion, BE3 on the middle portion and, 160 on the top portion. The idle jet has 50 etched in it. I greatly appreciate any information anyone can offer, thanks!!

Swap to a 100 (4-6 points above stock) and you'll be fine.

Thank you! Once the new jet is installed will I need to adjust the mix screw?

You shouldnt, but if you do, you want to find the spot where you have the cleanest acceleration from idle with the cleanest recovery back down to idle. Usually between 1.5-2 turns out from seated.

As MJ said, 4 pts over, if you get the unrestricted air filter (drilled or as factory made), +5 so 96 becomes 100, or 101 with the air filter.