Dude, the 1hp cylinder intake port has a restriction plug in it to make the intake port super small... Even if you take it out, it's not as large as the intake port on a stock 1.5 or 2hp, which means as much gas isn't getting sucked in... 20ish is about all a 1 hp will do stock... That is how they designed it. Take off your carb and intake and check it out... It's real easy to see what they did when looking at it up close. My first ped was a 1hp Puch Maxi Luxe... Here's what I did: Get a new or used 1.5 or 2hp top end, along with that 15mm carb and intake. You might have to do some airbox derestricting possibly... Of course figure out the correct jetting... I believe i was running a 66 or 68 main jet in my Puch Maxi with a biturbo 15mm carb and intake manifold and a stock airbox... I'm not posotive about that jet size though... Dan or Dave at 1977 Mopeds can hook you up with a brand new replacement cylinder for your puch that would work awesome... Ike from Ikes Bikes may also still have some NOS Puch cylinders... Also you should check ebay. Hope this helps.