Cylinder markings on wall any ideas??

[nambo-trev]

Anyone have an idea of what this marking could be from. It almost looks looked like a scrape mark but I think it feels raised? Can I get your guys advice??

 

[Jakobi]

Which jug is that Trev? Any markings/damage to the rings or piston? Have you tried cleaning it up at all with some carb cleaner and scotchbright? Intake side so maybe something thats been pulled through the intake? Reed valve?

 

[nambo-trev]

Sadly it's a ktm jug lol. I was just curious about ideas I thought maybe a chunk of carbon off the piston. I'm getting the boys at work to give it a quick hone so no biggie. Piston had markings to and bike ran like crap. I am trying to get it race ready for a buddy on Saturday. Should be all good but ill definetly have a peak at the reed block as well. Thanks bro!

 

[Jiikoo811]

Sadly it's a ktm jug lol. I was just curious about ideas I thought maybe a chunk of carbon off the piston. I'm getting the boys at work to give it a quick hone so no biggie. Piston had markings to and bike ran like crap. I am trying to get it race ready for a buddy on Saturday. Should be all good but ill definetly have a peak at the reed block as well. Thanks bro!

Seen very similar in KTM 300 2011 cylinder, 100hrs.. first piston change, but it was exhaust side of cyl.

 

[GMP]

If its actually raised from the nikasil surface, its likely deposited aluminum from the piston.

 

[nambo-trev]

How much can I hone it do you think before the nickasil will be to thin? I thought maybe half a thousand after looking at it

 

[GMP]

You can't actually hone away nikasil unless you have diamond hone. What they finish hone with after replating is a little different than your average flex hone that just deglazes. I'd start working it with some scotchbrite just in that area, you'll see results quick enough if its aluminum. Then just an even scotchbrite cleanup of the entire bore or a light hone deglaze. If nikasil is damaged then oh well you know what to do.

 

[nambo-trev]

Roger that Glenn ill give the scotch brite a try thx

 

[GMP]

Trevor,

You cant hurt anything that way, it will only remove what is soft.

 

[adv rider]

raised marking

You can remove deposited aluminum with acid. I have removed much worse, from melted down topends

 

[Wheelieman69]

What kind of acid are you using to clean with??


Wheelieman

 

[GMP]

I held off suggesting that, as you could do some damage. Hydrochloric or Sulfuric acid will work. A small amount on a brush applied carefully.

 

[Wheelieman69]

I think I'll stick with scotchbrite with my cylinder since I have never tried the acid I wouldn't want to mess it up at this point. But I do seem to have the same markings on the cylinder walls.

Wheelieman

 

[nambo-trev]

Are any of those marks raised or just coloured? The discoloured dullness is the nickasil flaking off isn't it??

 

[Wheelieman69]

They feel raised. Seems like I should be able to get them out but ?? To me does not seem that there is any flaking anywhere but I don't have a lot of prior experience on engine rebuilds either. When you run a fingernail across the marks you can't really feel too much and nothing your nail would grab either.


Wheelieman

 

[(F5)]

So its piston, the question is - why?

Check for airleaks, check for blocked jets & ask questions about if the jetting has ever been changed & consider a precautionary up jet.

 

[Wheelieman69]

Well I definitely need to rejet the bike once back together. It was really getting a lot of spooge out of the can after rides. Haven't gotten into the carb yet to see what's what with the jets etc.. I am waiting on a large part order from mark so I can start re-assembly. In the mean time I have been cleaning and going through the entire bike. Just started to pull clutch to look at plates and go further into pv linkage.


Wheelieman