I have a few of the ASP 61,s Have a few that run on a MACs tuned pipe The only problem Ive had from NIB was some sealant partly blocking the inlet on the fuel inlet nipple.
The main bearings fail after a few flights after run in, Quality brngs and no more problems.. And the dreaded O ring leak on the HSN Tube over the needle fixes that..
Other than that I find it a bullit proof engine..