Cam cap scoring

2005 6th gen with 55,xxx miles. Doing it’s first valve adjustment and went to put assembly lube on and noticed this scoring on the front head exhaust cam cap.

is this something to worry about?

The long line on the left looks like maybe dirt but the other looks like it was manufactured wrong. What do you guys think?

 

That's surprising to see.

So you're saying this in the first time you have been inside the cylinder head? Are you the original owner? Are you saying that you've owned the bike from new and now is the first time the bike has been opened up for a valve clearance check/adjustment?

Or, are you saying that the bike has had one (or more) prior owners before you, and if that is the case then it's most likely the bike has had at least one valve clearance check/adjustment done on it at some point?

Possible explanations for those odd-looking scorings:
1. If it's a prior-owner bike maybe somebody installed the Camshaft caps on the wrong camshaft (Intake 0n Exhaust or vice versa). Remember that Honda uses the "strike-through" method of identifying the correct orientation/placement of the camshaft caps, i.e. the cap for the Intake side camshaft will have the "EX" struck-through with 2 lines of dots, the cap for the Exhaust side camshaft will have the "IN" struck-through with 2 lines of dots.

2. If it's true that the engine has never been disassembled at all and the only camshaft item with scoring is this one particular camshaft cap, I'd be inclined to bet there was a slight mistake made by the technician who bored the camshaft journals. Or maybe, and I'd imagine this would be a low-percentage chance, a Honda factory technician miss-marked the camshaft caps, or maybe the camshaft caps were marked correctly but assembled improperly.

3. If it turns out that there are other camshaft caps that are similarly scored, I'd say it's possible the engine was allowed to run low on oil and this caused the scoring.

 

I’ve owned the bike since 14,500 miles. Although I am the fifth owner in five years. I bought it in 2010. The bike was wrecked, looked like it had been down on both sides. So obviously not treated very well. But with the low miles i doubt anyone has been inside the engine and I haven’t seen signs of anybody being in the engine before.
The cam caps were installed in there proper location when I disassembled them.
I didn’t see any scoring on the block side. I’ll look at the cam better tomorrow but didn’t notice anything when handling them.
I change oil every 5,000 miles using Honda oil

FYI: cyl 1 exhaust valve was at 0.30 mm spec is 0.35mm +- 0.03mm
Cyl 4 intake was at 10mm spec is 0.20 mm +- 0.03mm
Almost all of the other non vtec valves were right at there max in spec.

 

I'm surprised at your findings on the valve clearances. The bike has 55K miles, this is the first time you've checked clearances, and somehow all of the valves (except 2) are within tolerance? And not just within tolerances, but you're saying the valves (with the 2 exceptions) are closer to the higher end of the specification?

I've never seen an engine go that long without getting tight valves, not Honda, not Kawasaki, not Suzuki (I've never done valve work on a Yamaha so I can't say "not Yamaha").

If you can't find any more of this strange scoring anywhere else in the camshaft bearings I'd be willing to bet this is simply the result of a slight error during manufacturing, which means it (the scoring) has been there throughout the life of the bike (55K miles so far). If all this is true it hasn't caused any problems up till now, so I'd recommend you finish up your work, put the engine back together and don't worry about it.

Ride, enjoy, and keep on taking good care of it.

 

Got the rear head valve adjustment finished. There was some slight scoring on the exhaust cam cap also. Not sure what’s going on here but cost of repair is far to high to do anything about. I’ll ride it till the engine goes.

Here are my non vtec valve lash measurements after 55K miles. I was planning on doing the vtec valves but i’ve run out of time and I don’t think it’s necessary since the tolerance is a lot more and they don’t get used all that often. If it makes 100,000 miles I might check all of them then.

Spec is
intake 0.20 mm +- 0.03 mm
Exhaust 0.35 mm +- 0.03 mm

Cyl 1
Intake 0.20 mm
Exhaust 0.30 mm
Cyl 2
Intake 0.18 mm
Exhaust 0.33 mm
Cyl 3
Intake 0.18 mm
Exhaust 0.38 mm
Cyl 4
Intake 0.10 mm
Exhaust 0.33 mm