KTM 300XC Cylinder Plating Ok ?

[Swappa]

My new-to-me 300XC has a weird dappled pattern in the cylinder plating. I can feel a slight ripple with my finger nail.

Anyone seen this before?

Ok to run?

There are no marks in the head. 

 

Edited April 30, 2020 by Swappa

[SmokeX]

I say send it in.  That doesn’t look to good imo brother. ?

[Chevy_97]

I would replate it. It could just be the pictures, but I can't see any cross hatch either. 

[Braap2smoke]

^^^^ all the above

[Jackrides]

Never seen a chamfer as large as the top of the exhaust port. Anyone know if that isnormal?

[Swappa]

16 minutes ago, Jackrides said:

Never seen a chamfer as large as the top of the exhaust port. Anyone know if that isnormal?

I think you're referring to the second pic? That's the powervalve flapper with spotty carbon deposits on it. 

I'll post up some more pictures after cleaning the cylinder wall and with better lighting. The cross hatching is most definitely still visible in this bore, for the most part. Thanks. 

[Jackrides]

I'm a total newbie on power valves. Thanks!

[Bron-Yr-Aur]

If those are indeed divots (in) and not bumps (out) I personally can’t see them affecting much, as the piston skirt is the only thing in that area. Nothing is sealing against the bore in that area.

If you don’t see any dull, hazy areas (raw aluminum) particularly around the exhaust port, no vertical scratches that you can feel with your fingernail, or a pronounced lip at the top of the bore (where the rings stop at TDC) I’d run it. Introducing scotchbrite soaked with wd40 you can make some of your own crosshatching if you want. But i don’t spend $200+ unless the plating is actually damaged. I honestly would have no problem running that cylinder.

JMO 

Edited May 1, 2020 by Bron-Yr-Aur

[Swappa]

[Swappa]

It's tricky to get the camera to focus on the right section of cross-hatching, but the hatching runs all the way down to the ports.

Nickasil is also a different color to the cast aluminum cylinder, and I can see that it's present across the entire bore. The top of the bore where the ring stops (ring landings?) are not perceptible by finger nail, even though they look quite pronounced in the pictures. Based on this bike having original brake pads, and the wear and tear on the rest of the bike, I'm going to run this cylinder for one more piston. 

Thanks everyone for your input. 

 

Edited May 1, 2020 by Swappa

[Chevy_97]

Yeah I can definitely see the cross hatch now. I would deglaze it with a scotchbrite pad and run it for sure! 

[Bron-Yr-Aur]

From your description, it sounds like there’s a lot of life left in that bore. Enjoy! ?

[Swappa]

I just wanted to update this thread and thank everyone for their feedback. Compression is strong and the bike is running well. 
Powervalves were a bear to clean, and I did catch a whif of Castor oil during run in, so I assume the previous owner gummed everything up with mineral oil. 

E-start is still a work in progress, as is the overall chassis balance. First ride was with only 90 mm of sag and a soft fork. Bike was pretty scary in deep sand whoops, as you can probably imagine and it was only after I got home that I started to figure out why the bike felt sketch and low in the front. 

Bike has 5 hours on it since putting it all back together. 

Edited May 21, 2020 by Swappa