I used MMO and Sea-Foam in a couple of Shovelhead motors over the past year, one was an 89" Sidewinder with just a very few thousand miles, the other was a 74" that has so many miles on it you wouldn't believe me if I told you. Both ran strong and were not having any problems.
I just thought maybe with the bad gas these days this might help the motors.
Both motors suffered serious damage to the top end shortly thereafter from massive carbon build-up just above the top ring. Bad noise from the top end, cylinder scoring, piston damage, I mean bad. Upon disassembly nothing else was wrong. Just a lot of carbon and a lot of damage.
I'm not offering a post hoc ergo propter hoc argument, but I probably won't ever put that stuff in a Harley again, either.
I just thought maybe with the bad gas these days this might help the motors.
Both motors suffered serious damage to the top end shortly thereafter from massive carbon build-up just above the top ring. Bad noise from the top end, cylinder scoring, piston damage, I mean bad. Upon disassembly nothing else was wrong. Just a lot of carbon and a lot of damage.
I'm not offering a post hoc ergo propter hoc argument, but I probably won't ever put that stuff in a Harley again, either.