The first thing I noticed was carbon inside the motor, everything I touched left my hands black.
Here's a little-known item about "black insides" in this engine that I experienced:
In 1980 when I tore mine down (had just got [re]married, desired a bit more power) for its first oversize, I found the entire inside of the engine was jet-black, everywhere. It was much worse in the crankcases, even inside the side covers of the engine. I'd never seen this before, but I had been using Hondaline oil for the previous riding season as Castrol XLR was unavailable here at the time. I needed the local Honda shop to pull out the very stuck countershaft bearing (so I could get the cases washed at a machine shop), so I made an appointment and went to see their "750 specialist" (huh...). Upon seeing the inside of the lower case he chided me, saying, "When was the last time you changed this oil?". I told him plainly, It is Hondaline oil, bought from this very store, for the last 6 months." He told he he didn't believe me.
Everything was coated as black as if someone had poured black graphite into the engine, from that oil. By the time I finished the rebuild I had located a case of the XLR and went back to using it after the rebuild. But, I have NEVER seen as black an inside of this engine as that was, and touching it made everything black like charcoal.
Exxon used to sell graphite oil back in the mid 70's. I used to use it until I saw that it did separate and coat the oil pan and came off in sheets like black paint. Thought that it couldn't be good for the gallies and top end. Never had a problem with the engine though. At that time Mobile started their Mobile 1 oil. It came in a metal can rather than the fibered oil can most company's sold. I used that in my car for a long time until I realized the reason Mobile 1 came in a metal can is because it caused engine oil leaks. It must have shrunk the oil seals in the engine. Cost me over $700 to get my car's oil seals replaced.
-P.
-P.
The black 'stuff' inside the engine would stick to my fingers readily, had to keep gasoline on hand to clean it off! It was slippery, too. But, zinc is grey like cement, so I don't think it was that. It didn't HURT anything, and the bearings were all 100% good everywhere, no seals leaked or anything like that. The Hondaline oil, though, just did not quiet the top end like Castrol's XLR always did (and Bel-Ray's EXL Mineral does now), and it felt somewhat listless at 80 MPH hiway speeds (hence the teardown, I thought maybe the engine was getting tired?). Maybe it really only needed some more Castrol? Well, too late after that, it grew to 1st oversize and got a port job over that winter.
However...a friend had a nice, new CBX then, and over that winter he added a turbocharger to it. He was using the Hondaline oil. About mid-next-summer (1981) it started weeping oil at several seals, and he blamed the Hondaline oil for it. After replacing the seals that Fall he switched back to Castrol XLR, too. He said it ran much cooler with the Castrol (and I'd say cleaner, inside!).
When I took mine down in 2006 after it sat from 2001 (following cancer and recovery) it had been using the Bel-Ray EXL, and I actually parked it with old oil in it (shame...). There was not a hint of corrosion nor rust nor crust anywhere inside, sweet and clean-looking, so I just replaced the primary chains (126k miles) and piston rings (bit of rust in one cylinder then) and put it back together. Those rings never quite seated 100%, which was what led to the 2013 top-end rebuild. That's not the oil's fault: re-ringing used bores in these engines NEVER makes for a good ring seal (even in the Honda singles or twins).
