How bad is this cylinder?

From my 1988 Cr250r.... advice?
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SRAD97750

Moderator
Staff member
If it was my bike, I would be sending the cylinder out for work and I would do some work to smooth out that cylinder head. Get some scotchbrite on those dark areas to see if the scoring is 'fingernail sensed.' Is that pitting in the cylinder walls at the intake port?
Something terrible happened in there at one point, but the current piston is certainly post cylinder head damage.
Hows the piston look? You can see the skirt through the intake and exhaust port. (if you don't want to disassemble yet)

I would do a top end and check bottom end specs. Shouldn't be too expensive, you caught this one before any real damage occurred. -BIG DAN:thumb:
 

SRAD97750

Moderator
Staff member
Is it just me or does that look like its been welded half way up and at the top of the bridge in the port???
This engine has seen something horrible. But looks like it could be cleaned up pretty easily with proper maintenance.
Just like adopting a dog someone else abused, all they need is consistent, proper love, and they will turn around. -BIG DAN:thumb:
 
it had a broken ring or skirt in the past Im guessing. This is from me seeing the head dings in my own bikes years ago, looked the same. The current piston does not have the matching damage. If the plating is worn thru on the exhaust bridge in the pic then you need to re-chrome that bore. But, if it cleans up then I would use it. The brown is from blow by of the rings being worn at the bridge area. Piston and rings replace are up to you.
 
It's magnetic. Sleeve? If so... re-sleeve? I know it's not as good as factory. At least I hear. I found a La-sleeve for $120 on eBay. That's about it


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It's magnetic. Sleeve? If so... re-sleeve? I know it's not as good as factory. At least I hear. I found a La-sleeve for $120 on eBay. That's about it


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Steel sleeve you can just hone or bore depending on how deep the gouges are. That one looks like you can hone. Wiseco piston may need to be drilled below the rings because of the exhaust bridge. That's possibly the reason why you see a burn streak there.
 
It's magnetic.

How magnetic is it? Does it barely stick, or nice firm grip? Some cyl have enough ferrous metals in the mix to draw a magnet but not completely stick. Doesn't look like a sleeve to me. Move the magnet around to different places it shoul grab hard everywhere you touch if it is.
 
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How magnetic is it? Does it barely stick, or nice firm grip? Some cyl have enough ferrous metals in the mix to draw a magnet but not completely stick. Doesn't look like a sleeve to me. Move the magnet around to different places it shoul grab hard everywhere you touch if it is.

True. Also, can you see the sleeve in the ports, and on the skirt of the jug? Additional photos would help the viewers determine this with you.
 

SRAD97750

Moderator
Staff member
The ports tell a story of nikasil.
I would be sending this one off to a plater or finding a usable one on eBay.
After a fresh cylinder job, if you change the piston/rings regularly, it should last a lifetime. -BIG DAN:thumb:
 
How magnetic is it? Does it barely stick, or nice firm grip? Some cyl have enough ferrous metals in the mix to draw a magnet but not completely stick. Doesn't look like a sleeve to me. Move the magnet around to different places it shoul grab hard everywhere you touch if it is.

It grabs all over, I don't have a very strong magnet though


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