Experimental category, maintenance, parts, and continuedairworthiness requirements

Thanks for helping to clarify this. My glider was imported prior to the issuance of the German TC. CFR part 43.1 (b) (1) is certainly very clear. I guess the operating limitations become the primary document concerning these issues.... JJ, I actually currently have another glider registered Experimental, with a recent set of operating limitations, and they do state that the glider must be operated and maintained in accordance with the manuals. Let me reassure you that I would never deviate from operating in accordance with the POH. My question really centered around whether I could legally undertake work on the engine myself, and whether I could make what I deem to be intelligent minor parts substitions, i.e., changing to iridium spark plugs, for instance. I also see that requirements in the maintenance manual such as changing seat belt webbing every twelve years has not been complied with, so wondered whether this rendered the glider non-airworthy from a legal perspective. I'm a bit of a gear-head and DIYer, so I'm happy to learn that I won't be breaking the law if I replace my own carburetor diaphrams....