Mild cylinder scoring--is this an issue?

[BTraci]

On a 117" with ~7000 miles, had been in storage so tore in down to make sure everything's good--there are a few mild scratches on the front and rear of each cylinder--see photos.  Can't feel them with a fingernail, doesn't catch at all.  For 7000 miles of often high-temp riding, is this pretty normal or something to be concerned about?

[Helmwurst]

That looks more like a sharp edge on a ring that smoothed out after the initial start up. JM2C

[Don D]

My eyes go to the carbon build

[Norton Commando]

My eyes go to the carbon build

Mine, too.

And the clean metal around the perimeter suggests it's burning oil.  What has the oil consumption been?

Jason

[kd]

My eyes go to the carbon build

Exactly what happened to me.  I lost the interest in the scratches.  The cylinder bores look cherry to me.  Those so called scratches could be as a result of minor contamination on the piston skirt or the first break in revolutions doing heat cycles and should seal well.  Most of the marks stop at below the ring pack height indicating possible dirty skirts.  The ones that don't could still be contamination from the carbon blowing off the pistons or ring break-in but at this point look very very minimal.

I also would investigate oil consumption by inspecting signs of valve stem build up etc.. The carbon may be from too easy of a break in and the ring seal being poor.  If you slide the barrels off and see staining on the piston that is below the ring pack it almost certainly is poor ring seal.  Alternatively, it may only be carbon from running the head breathers into the breather.  I would check the rocker stands to see if the drain hole has been re-drilled and do so if not, then go to external venting if it is not already. 

To me, the cylinders look real good.  At twice that mileage I could read the casting and stamped numbers on my pistons with a bore scope.  I think if you have an issue at all it's related to what looks like carbon from possible oil consumption.  The clean perimeter surface on the pistons often indicates poor ring seal and oil getting by to burn and cause the carbon.  Measure your quench (squish) before slipping the barrels of to check the piston skirts and rings.  If you have a tight quench clearance like .030, that will also aid in keeping the piston deck clean around the perimeter (at least where the head surface and piston meet) and it would therefore probably be OK.  Amber staining below the rings however will be a sure indicator of poor ring seal but may be faint at 7000 miles.   

This is my opinion only and based on your very few pics.  Have an expert confirm it by real hands on inspection while you have the opportunity and the parts "in hand",

[BTraci]

Thanks all; a few years ago I went from external breather to running it through the intake.  Doesn't burn oil if I keep it at the low end of the dipstick, but way too much oil coming from the breathers into the intake.  Time to redo the external breathers

[Hillside Motorcycle]

We showed photos of an un-run piston/cylinder on our company Facebook a while back, that we had rolled the engine multiple times while checking valve to piston, and deck height, as an alert to those that suspect something out of the ordinary.
Looked about the same.

[guydoc77]

I have seen very similar vertical "scratches" each time I have bore scoped my 107". It is 11.3 static, does about 125 squared, give or take, and now has 38000 miles on it since it was built at 68000 miles on the bike. I recently was bored (winter) and took the AC off and stuck the bore scope through the TB and intake and the front intake valve has a lot or carbon on its back side. Maybe a guide is loose or a valve seal worn. I then bore scoped the cylinders and they once again looked pretty much the same as yours in the pics you posted. They have looked like that repeatedly over the last five years so I am not real concerned. This motor does use about a half quart in 5K miles using Mobil 1 synthetic. And I have the R&R Overflow AC with the external breathers. 

[RideWG03]

I've heard that the aluminum heads twist a bit when being torqued down and it causes this and no way to avoid it  The old iron heads didn't have this issue.  Just what I've been told, so who knows.

[Boe Cole]

I've always gone with the old 'if you can't feel it with your fingernail, it isn't there'.......

[MikeL]

Those marks are far from scoring.
Scoring would be a transfer of metal
Could the oil residue be from the likes of say a product like seafoam? It was in storage?


                                                                                                    MIKE

[Pete_Vit]

My eyes go to the carbon build

Mine, too.

And the clean metal around the perimeter suggests it's burning oil.  What has the oil consumption been?

Jason

[Hillside Motorcycle]

The clean perimeter would be the squish.

[kd]