Whoa- this CB1100 dropped a valve seat-

[the Ferret]

While that may feel good, I doubt it actually does much for the combustion chamber of your bike. Removing carbon deposits requires a lot of heat, and Honda worked hard at making sure our bikes don't run too hot with large air fins on the cylinders, an oil cooler and oil channels in the cylinder head around the spark plugs.

However engine components like pistons, rings, valves, cam chains etc are wear items, and only good for so many cycles. You can use those limited number of cycles up quickly or slowly.

Personally I think the "Italian Tune Up" is the placebo effect whereas if you believe you are doing something good for your engine, then you feel better about it, and imagine that your bike is running better, but I do believe the very smart engineers at Honda knew what they were doing when designing this bike and that running it anywhere in the rpm zone from 2,000 rpms to redline for as long as you want will not be detrimental to your engine.

[pekingduck]

That is an unusual failure, and I'm guessing heat was the cause, but can't guess on the oil in the combustion chamber. There is no apparent cracking between the valve seats, and there appears to be enough distance between valve seats.
On big displacement air-cooled fours, lack of heat dissipation is a limiting factor on power output. Honda put spark plug heat sinks on the CB1100 for that reason.

[PowerDubs_imp]

While that may feel good, I doubt it actually does much for the combustion chamber of your bike. Removing carbon deposits requires a lot of heat, and Honda worked hard at making sure our bikes don't run too hot with large air fins on the cylinders, an oil cooler and oil channels in the cylinder head around the spark plugs.

However engine components like pistons, rings, valves, cam chains etc are wear items, and only good for so many cycles. You can use those limited number of cycles up quickly or slowly.

Personally I think the "Italian Tune Up" is the placebo effect whereas if you believe you are doing something good for your engine, then you feel better about it, and imagine that your bike is running better, but I do believe the very smart engineers at Honda knew what they were doing when designing this bike and that running it anywhere in the rpm zone from 2,000 rpms to redline for as long as you want will not be detrimental to your engine.

You'd be amazed how quickly temps build when WOT all the way through a gear.

It's not uncommon for headers to glow on a dyno when doing a full power run. Spark plugs and exhaust valves get VERY hot.

I'd love to have one of those IR cameras- I could get some data points for you.


But as to the commentary of if this particular bike had been burning oil....here are 2 other CB1100 cyl heads on Ebay currently- also nasty gunked up chambers. One worse than the other...

https://www.ebay.com/itm/325754437342

https://www.ebay.com/itm/325754437318

[1973cb750]

that is the second one i have seen do that the other was a bike i bought parts from a while back got scrapped i think