I recommend that you Google Four Stroke Engine on the web. There are a lot of how things work pages that will get you well grounded in basic engine theory. Terminology is one of the biggest challenges when first starting out. Valves, cams, rockers, tappets, rings, wrist pins, big end and small end bearings, main bearings... and on and on.
All 4-strokes run from the same basic engine theory, so whether a flat head, overhead valve, single overhead cam or dual overhead cam, they all run based on the same principles and all have the same major parts for the most part.
You just don't go out and buy new oil rings and install them. You need to check the condition of the internal engine components, measure for wear, look for damage and perhaps modify to a new size to fix the problem or restore the integrity of the system you are working on. It's not like tires, which you simply replace when they wear out.
regards,
Rob
honda305.com Forum
Vintage Honda Owners, Restorers, Riders and Admirers
White smoke out of left muffler?
The oil ring is the lowest ring on the piston. It acts as a scraper removing excess oil from the cylinder wall as the piston is in it's intake or combustion stroke. If the oil rings wear out or break, the compression rings don't remove the oil and it stays on the walls and is burned off during the combustion stroke causing the smoke. Replacing these parts is not overly difficult, but if you're not mechanically minded, I would suggest getting some help if you decide to do it yourself. If you do decide to do it yourself, there are plenty of people on this forum who are willing to answer your questions, so just post if you're not sure.