Lot's of posts mention the RATTLE in the Malossi, I personally do not have this, however I think it may be due to the light weight construction of their variator, and the fact that you can tap it w/ your finger or a screwdriver,ect.., and get the same tone, I think they call it a bell for a reason. My thought is all engines have different "balance" issues, so some may resonate different areas at different rpm's. I just try to stay out of the sour note ranges. Usually I just hit it and hang on. Just a thought on rattles.