It is a common question across the scooter world. What is the difference between the Piaggio Hi-PER-2 and the Hi-PER-1 engine?The engine used in almost all models including the Piaggio NRG, Gilera Runner, Piaggio TPH, Gilera Stalker, Piaggio Zip and so on. Answers are usually very brief and inaccurate. Therefore TuningMatters.com is giving you a proper review on the differences of these 2 engine blocks.
First things first
First of all I want to outline that additionally to the differences that I list here, there are some further things to consider. The new engines are also available as a disc brake version. Unless you replace the complete brake system it is not possible to swap your drum brake engine with a disk brake one.
The Hi-PER-2 block is sometimes also called Hyper2 and Hiper2 engine. The old Piaggio engine is sometimes also referred to as Hyper1, Hyper, or Hiper1 engine.
In this review I will only discuss the engine blocks for 2-stroke carburetor engines. The injection “purejet” models are currently still not a good basis for tuning and were therefore left out.
Also, there is a Hi-PER-2-Pro version. It is used in the latest Runner and NRG models. It is not true that this engine is the “purejet” injection model. However, the only difference we are aware of is the low-pressure connector next to the intake. If you know more about this model please let us know in the comments. It is not covered in this review.
On all pictures in this post the Hi-PER-2 engine is always the top one, whereas the old Piaggio engine is the bottom one. The pictured engines are in a used condition and especially the old model has seen some better days…
Can I replace my old engine with a Hi-PER-2 engine?
The most important thing to know is that both engines can be used interchangeably. The differences are minor and most of the parts like cylinders, reed valves, exhausts, manifolds, etc. can be simply fitted to the other engine. The variomatic in the new models has changed slightly and should therefore be replaced with the new one. The same is true for the torque driver and the primary gear.
It does not matter so much if you buy a LC or an AC model since they both are the same. To fit the original waterpump to an AC block tho, it is necessary to drill a little hole…
Where are the differences now that matter: Take a closer look at the picture (all pictures always show the Hi-PER-2 on top and the old Piaggio engine on the bottom). You’ll notice two screw holes on the old engine. these were used to replace the gear oil and were very annoying to all of us. With the new engine these screws have been replaced with a drilling on the side of the engine where an oil dipstick is now used. To me this is one of the biggest improvements of the new engines…
For the next difference we will need to turn the block around. The gear box has seen some additional changes. On the old models the primary gear used to have its own ball bearing inside of the block. On the new model this has been moved from the block to the transmission cover to improve stability. This also means that the primary gear is not interchangeable between these two engines!
A last notable difference can be found on the ignition side of the block. The newer models use a cable connector whereas the old blocks had the cabling going through the block. I believe this should be mentioned even though it should not be a problem for anyone to build a workaround if he runs into any problems with the cables.
Piaggio engine gallery
I have created a gallery with in detail, high resolution pictures of both engines for you to compare. Find this gallery below. The Hi-PER-2 engine is always the top one, whereas the old Piaggio engine is the bottom one.