Sounds like the valve adjustment was way too tight at some point. 20% of my 17,000 miles is cruising through town alternately at 3,500 rpm/ coasting with the clutch in, with no problems.
Sounds iffy. It seems our bikes have a tendency to coat the filter with oil (lightly) through time, due to the PCV and airbox design. If anything, this would restrict airflow and the bike should adjust.After fixing the burnt valve issues I had tech do a service. Upon taking out the air filter tech thinks he knows what may have caused the burnt valves. Air filter was covered in oil. He said the only way this could happen was if the bike spent a lot of time on its side....like it did after an accident that happened not long before this happened. He said the oil would fool the O2 sensor into thinking the bike was running rich (when it wasn't) and cause it to adjust it to run leaner when not needed. I'm hoping this was the cause and I can get back to enjoying my bike again without future issues. Thank you all who have replied to this thread.
Thats what I'm trying to determine. I had them replaced brand new after the exhaust side burnt from hubby lugging the engine...Toasted spark plug diagnosed that one. Then, 3000 miles later the intake side burnt. Tech says everything was in spec and was stumped as to the cause. He thought that The oil in the filter may cause the O2 sensor to think it is running rich causing the O2 sensor to adjust it to run leaner. He was grasping for whatever might have caused it but really had no solid answer that he could say this is definitely it. I really want to know if I should sell it now with the rebuild before it happens again..... He says Honda's are what he would buy over any other bike hands down based on a mechanics perspective (although he really hated working on my cbr because of all of the clips to get fairings off). He says they are virtually indestructible (accept mine apparently) so he is really thrown off by this.That may very well be the case, as running lean indeed burns valves. But it's not going to come from an oiled up filter. All that will do is reduce airflow, ENRICHING the mixture, not leaning it out. Just saying.
Burned valves can also come from too tight of valve clearances. 600 miles for the first valve adjustment on these bikes; if this service was not conducted, regardless to whether your clearances were correct at the time of measurement after valve failure, could be a more likely culprit.
If I had burned valves in my properly maintained motorcycle after 15k and the only explanation the tech could give me was it was caused by an oiled up filter, I'd laugh in his face. My gut, you may have just gotten unlucky and landed a CeeBee with defective valves.