Yz125 is this cylinder reusable?

[farris243]

Fried this Sunday. Top end kit already here just trying to get some advice on the damage to this cylinder. Can't find much about it on the internet so what do y'all think?? Would you re use this? Or too dangerous? The walls are fine just the top of cylinder where it's chipped/pitted. It also did it to the head, you can see it if you zoom in on the pics. Crank is perfect and in spec. And would like to keep it that way. Don't want to burn another piston like this. You can see a crack on skirt that almost broke off. Super close call. Thanks and every bit of advice helps!

[dirt bike rider78]

Ok what you want to do is run your finger around the inside of the cylinder and if you can feel any scratches or anything like that you can't reuse it

[farris243]

Inside is super smooth it's just the chipping at the top

[farris243]

Ok what you want to do is run your finger around the inside of the cylinder and if you can feel any scratches or anything like that you can't reuse it

Inside is super smooth it's just the chipping at the top is only damage

[YZDOC]

Inside is super smooth it's just the chipping at the top is only damage

 

That chipping looks like it is on the outside of a steel sleeve. Does this jug have a steel sleeve? Lets have some photos of the bottom and focused on ports. 

[dirt bike rider78]

Then I would replace the head

[farris243]

That chipping looks like it is on the outside of a steel sleeve. Does this jug have a steel sleeve? Lets have some photos of the bottom and focused on ports.

That I don't know. It's all original oem. 2003 yz125 and already left the house I'll try to get those pics tomorrow

[YZDOC]

That I don't know. It's all original oem. 2003 yz125 and already left the house I'll try to get those pics tomorrow

 

I would believe you on the all original OEM if "you" are the original owner. And it that is a nikasil jug, you "will" need to have it re-plated. The head can be cleaned up by machine shop or send it out also. 

 

Post up when you can. 

[farris243]

I would believe you on the all original OEM if "you" are the original owner. And it that is a nikasil jug, you "will" need to have it re-plated. The head can be cleaned up by machine shop or send it out also.

Post up when you can.

Yeah 100% original. Sat in a shop for 13 years. Cleanest early 2000 yz I'd ever seen. I'll probably just buy a complete one rather than re plating if it is trash. Kinda thinking about a 144 anyway to see what all the talk is about.

[farris243]

Cow pasture hours* never touched a track

[YZDOC]

Run that jug the nikasile will flake off worse than Kellogs Corn. 

[Muffintop]

You've gotta have an air leak or something. holy smokes

[farris243]

You've gotta have an air leak or something. holy smokes

Well I thru fmf fatty and shorty with stock jetting. I've heard that can make super lean issues like this. And first couple rides with it was in deep sand. Figured that's what caused it. Hopefully not air leak somewhere!! Like a gasket air leak??

[01cr250.677]

Cow pasture hours* never touched a track

Those are the bikes I avoid. Wide open acrossed fields seems to be the usual on em. I've seen what trail riding does to bikes as well so I try to stick with track riden bikes from a guy that keeps his stiff 100% all the time.

[01cr250.677]

What's your plug look like? Could he detonation issues. But you could be drawing air from a boot or reeds I'd check those

[yz250474]

_{it don't look good to me... can someone explain the pitting at the top of the cylinder? looks like it needs a lot of work IMO.  the pic's of the head aren't clear at all.}

Edited January 13, 2017 by yz250474

[yz250474]

Those are the bikes I avoid. Wide open acrossed fields seems to be the usual on em. I've seen what trail riding does to bikes as well so I try to stick with track riden bikes from a guy that keeps his stiff 100% all the time.

Im the guy that run's across field's wide open cow $hit and all... if I got a problem, I fix it...   I try my best to keep my bike 100%,  but I don't try to sale my bike.

Edited January 13, 2017 by yz250474

[CaptDan]

Im the guy that run's across field's wide open cow $hit and all...

 

Braaap!

[bikedude987]

Definitely a lot of detonation going on.  IF the pitting is not in the swept area of the rings (doesn't look like it is) AND the O ring/mating surface of head gland is unpitted, I would say you can run it.  

 

You ABSOLUTELY need to either jet it properly or find and fix the air leak.  This is NOT NORMAL

[DezertMobber]

in my opinion i would say to file/grind down the chipped area to get all the lose particles that may fall off into the cylinder while riding. file them lightly just to remover the damaged area to a smooth finish (solid) 

DO NOT TAKE MUCH OUT.