I have a 2008 Apex MTX that I use for trail riding. I know this is not the ideal sled for this but its what I have. I would like to lower the engine rpms at cruising speed, say 40 - 50 Mph. it currently runs at around 7-9k rpm at this speed. I would like to lower it to 5-7K. It seems its revving pretty high for cruising speeds, probably because the OEM setup is for mountain riding. I don't want to spend much money on this, so I was wondering if changing out the rivets for heavier ones would accomplish this. This is my current setup, not sure what rivets these are, do they look like OEM? there doesn't seem to be a head on the rivets, they are pretty much flush with the weight. Any recommendation's for different rivets that will lower the cruising RPM? should I put a rivet in the empty slot?