The motor is failing on high rpm

I didnt knew that this problem could be solved...thanks norman, i will think if it's worthless or not...

today i take a ride, and the motor is really bad (but is a bit better than a few days ago).

In flat i cant run higher than 40km/h, and the aceleration (power, torque, whatever) is really poor :S

The fact is this motor has already 2200km, and that's not so bad for this motor, but i have to admite that i did some bad runs (high speed's down a street...things like that :S)

Are those new rings the same thickness as the old rings? If they are too thin for the piston grooves, that can't be good.

Plus, wouldn't new rings in an old cylinder take some wear-in time for max compression (and top end)?

In fact, the new piston rings are thinner that the stock old ones. can that be a problem?

I will change them, then

Thanks