Valve hitting piston? (81 gpz550)

I heard my valves getting noisy and figured I needed to check/adjust my valve clearances soon. Well, I didn't get to it soon enough and I started hearing a louder knocking coming from my top end. I took the valve cover off and checked my clearances and most were out of spec (I already figured that). Decided to take a deeper look so I removed the head. After removing the carbon build up on the valves and piston tops I noticed #3 piston had little dents where the exhaust valve comes down, and on the #3 exhaust valve, right in the center, there's what I initially thought was just really tough carbon build up but now I'm thinking could be little chunks of aluminum from the piston that have been squished on.

Does this look pretty bad? (See pics) will I have to get some valve work done? Or would I be able to just adjust the valves (already received the shims I need) and be good go?

Check your #3 choke flap. It could be missing, and it could be what you see on the valve.

They need to be checked periodically to make sure they are not breaking off.
s3.amazonaws.com/gpzweb/TK22mainPage/TK2...chokePlateFlaps.html

Have you check #3 spark plug if a piece of ceramic broke off? Have the cylinder surface scratches ?

Good suggestions. Fortunately cylinder is not scratched and spark plug is not busted.

I think loudhvx is on to something. My current set of carbs are all in tact but the ones that came on the bike when I bought it were in lousy shape. I think I vaguely remember a choke flap missing. I'll have to dig them out and verify. That would explain that extra material that is flatted on to the valve. I don't think that would be the source of the knocking sound however as that just recently developed and I switched out my carbs a while back, maybe like 1,000 miles ago. The sound could be that the valve clearances were just so out of spec perhaps.

I guess at this point I should just try and remove as much material as possible from that valve face, replace my valve shims as needed, get it all back together and see if the noise is gone.

That is baked on carbon. Have you synced the carbs?
Steve

SWest wrote: That is baked on carbon. Have you synced the carbs?
Steve

Hey Steve. The carbs were synced about 1k miles ago. I could be wrong but the reason I don't think it's carbon is because I had carbon build up on all cylinders and I was able to scrub all of the valves and piston heads clean with a wire brush and carb cleaner. It wasn't easy, it took a little time, but the rest look good except for that valve that looks like it has two bits of material flattened on it. Also the little dent marks on the piston head are weird.

If it is carbon baked on, how can I go about getting it removed? And would that suggest that cylinder 3 is running too rich compared to the other cylinders?

It's a sign of a healthy engine. I used a grinding bit in a drill to remove it. It does look like something was bouncing around in there.
Steve