scratched cylinder

[kx986]

I had the cylinder off my kx250 for a top end job this week and realized that there were 3 scratches on the front of the cylinder wall. They are hardly noticable by feel, but it's in a high friction area (plus i'm running a dual ring wiseco). How much life do I have left?
If I need a new sleeve, would it be easier/cheaper to get a new sleeve pressed in by a machine shop, have it bored, have it re-nickasealed, or just buy a new cylinder?

 

[Ron2stroke1]

well if you need to get it redone go with nikasil. It transfers heat better than a sleeve. I costs about $200 depending on where you get it done.

 

[gthoma23]

I had the cylinder off my kx250 for a top end job this week and realized that there were 3 scratches on the front of the cylinder wall. They are hardly noticable by feel, but it's in a high friction area (plus i'm running a dual ring wiseco). How much life do I have left?
If I need a new sleeve, would it be easier/cheaper to get a new sleeve pressed in by a machine shop, have it bored, have it re-nickasealed, or just buy a new cylinder?

depends on how bad it is. where were the scratches? the highest friction part in the exhaust bridge, just because of the amount of heat. i have some pics of my CR cylinder on here, either look at my threads or the 2 stroke section and look for CR engine pics. i was able to clean it up quit a bit by doin the muratic acid trick. if ya don't know what that is, it's basically a deluted form of hydrochloric acid. then i used a scotch brite pad with WD and scrubed the :p out of it. looks pretty good now, but they say it has to be serviced.

and i don't know what year ur KX is, but i'm almost postive it's plated, but it isn't nickel, it's electro fusion. but if u get it replated u can get nickel i think...which is way better. like the guy above, sleeves suck cause they hold head, and they wear alot faster, and after havin mechanic install, probably more.

i'm new to this, so most of this is info from other guys on this site or thumper. like i said, check my thread any u'll find everythin u need....with pretty pictures too :laugh:

 

[VISaki]

I'd say get it fixxed your just gona end up damage it more lil by lil..maybe if you switch up your fuel ratio it'll last but you want it to be nice and well lubricated....I'm about to do a top end rebuild aswell...and might do the sleeves to save me a damaged piston in the future.

 

[kx986]

it's a 1999 and yeah the scratches are up by the exhaust ports. It looks like I should just have it recoated. Of course I hear Kawi's are the most expensive to get done

 

[AV8R]

I would run it, unless the scratches are all the way through the nikasil plating. What's the worst that could happen? You end getting it replated later because the plating starts flaking off? I would keep an eye on it to see if that occurs but you'll probably know from a significant loss of compression.

I'm running one now in a YZ250 that is scratched and so far the only difference is that I have a 5% compression loss as compared to before it was scored, presumably from blowby.

 

[gthoma23]

I would run it, unless the scratches are all the way through the nikasil plating. What's the worst that could happen? You end getting it replated later because the plating starts flaking off?

that is one of the worst things that could happen, if that plating flaked off, it's so strong that it could completely destroy the bottom end. no1 can tell how bad they are, w/out at least pics, and then we still can't feel it. what i've been told by every1 on here and mechanics all say, if you can catch it with a finger nail it needs a re-plate. i could catch mine, but after deglazin it, i can't

Seriously, do what i said before u do anythin. the only thing u can loose is some time. muratic, scotch w/ WD-40, soapy water, blow water with compressed air. after that, u should know what ya need.

 

[VISaki]

Kawi's are expensive cause they never really get beat up and when they do its a hard process....if anything just get a new sleeve with the ports ingraved already might save you time and money just buying a new sleeve.