Motorcycle Repair/Vintage Honda Motors
Hi, This is a general question about Honda Motorcycles. I had a 1983 CB550SC Honda Nighthawk (inline four with a shaft drive) and it it was the greatest bike but the engine started to burn oil and smoke badly at about 60,000+ miles so I sold it but I miss that bike. My question is if you buy a 80's (maybe 400-750cc)smaller engine vintage Honda don't all the old rubber engine parts and gaskets dry out? Kind of afraid to jump into a older bike as much as I would like one because I don't want to get into engine rebuilding. Right now I have a modern big engine cruiser and it really isn't as much fun as my smaller 80s Nighthawk. Would appreciate if you could tell me what to look for and expect in buying an older vintage bike and any suggestions in models to choose for reliability and durability. Thank you for your advice
Harry, in the big picture of vintage bikes, in general, all of the rubber parts (seals and gaskets) are going to deteriorate over time. At 60K miles on your little CB550SC, the rings were probably worn, plus the valve stem seals had hardened up allowing oil to get sucked past the valve stems.
You can't avoid age as a factor, but if you find a bike with really low miles (less than 10k) then there is a fair chance that it might hold up for a few years without major work. Most engines allow for seal replacements w/o tearing down the whole engine. Valve stem seals are not such an easy fix, however. The head has to come off, remove all the valve springs and replace stem seals, assuming that there is no excess wear in the guides.
The 1990s-2000s CB750SC is renowned for longevity, but they are out of production for a number of years now. The engine architecture is pretty much the same as the 550-650-700SC engines, so would be something that you would be comfortable with right away. Unfortunately, the 750s are chain drive instead of shaft drive, though.