So how many Bassholes are running Yamaha? I'm the proud owner of one even though it's a finnicky little diva sometimes. I'm the third owner of a powerhead that's a '96 and never been rebuilt. I've had one of the heads off and the pistons have a little bit of rock in them but compression is still over 100psi on all six and within 1-2 psi of each other. If I ever have to rebuild it I'm going to do everything it takes to get the highest compression possible to turn it into a real screamer.