An NSR that was here (no names mentioned) was running (RM125 I think) Wiseco pistons. It had a bit of an issue on first start up which was a crank seal. We replaced that, but I mentioned that the bore looked a little tight. Sure enough, half a lap of the pit and it nipped. Not a piston problem, just not enough clearance.
My CR250 had a buggered (std) piston when I first bought it. I replaced with a Pro-X, which cracked after about 100kms. Swapped this for a Wiseco and never had a problem again.
My CR500 ran all last year on the same Wiseco piston. I pulled it apart many times, but I only changed the rings once during the Supermoto season. It was a bit wobbly come the end of the year, but still worked fine.
Fitted Wiseco to various other crossers 125/250 with no reported problems.
I also had special one offs made that have won the 160cc 2 stroke drag race championship in Thailand two years running, and are leading the championship now. Fastest time and highest terminal. We tried various other types/makes and they've all flown apart.
Wiseco boiler pistons seem to be ok too. Heard scarey reports of hi-comp CRF450 pistons going pop, but not had one break that I've fitted.
We're also looking to make some specials boiler slugs for the 160cc 4 stroke drag racer here and it's Wiseco I'm in touch with. I'm very happy with their service and technical help.
I've never really given any other piston make a good enough chance to say which is the best, but I'm happy with the way that Wiseco have worked for me and with me. Let's just hope the pistons they made for my 300 stay together, or they'll be getting a phone call
