We have over 30 years experience with all makes and models rebuilding 2 cycle engines used in the ultralight aircraft. All engine rebuilds include photos of the condition when shipped in. We record the serial number tag We photo the disassembly and all parts replaced with Rotax part numbers and we photo reassembly phases for your confidence.   You will also get documentation which will further aid you should you decide to sell your aircraft.  For the last 21 years we are the only ones in the repair business to do this. Here's what we do;   Photo engine before teardown Check compression before and document in writing and photo Remove and photo the drive system Remove and photo all housings and recoil assembly Plug all ports and Walnut shell blast casing and photo Disassemble the magneto side and photo Remove exhaust and intake, bead blast exhaust manifold and walnut shell Blast intake manifold Remove heads, cylinders and pistons Deglaze cylinders, cross hatch cylinders, check all tolerances Replace pistons (if needed), rings, wrist pin bearings-caged and wrist pins replaced Split the crankcase- we always replace both mag and pto outer bearings and seals Walnut blast the crankcases upper and lower and true the halves Clean and reassemble with a special non hardening silicone on all gaskets except exhaust(not auto store RTV) All gaskets replaced and tolerances rechecked on engine at reassembly and documented All nuts and bolts torqued to specs documented Flywheel key replaced Compression checked and documented Ignition timing checked to specs New O ring for gear case housing mount Documentation with photo packet recorded with document number and break-in data time sheet