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Discussion Starter · #1 ·
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Hi, I am trying to revive my CBR1000RR so I am rebuilding the engine.
what are your thoughts about these scratches? is a honing and new rings enough or would I need new pistons and re bore.
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Generally, on any engine, if you can run a fingernail over the scratch, and feel the bump it's too deep and needs to be corrected.
 

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Ace Tuner
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is a honing and new rings enough or would I need new pistons and re bore.
How many miles are on the engine?
Measuring the cylinder bore with a dial bore gauge and micrometer, then the pistons with a micrometer is the only way to know how much wear you have. (Piston to cylinder bore clearance).

S F
 

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So would you not be concerned with the vertical scoring on the cylinder walls?
Figure that will buff right out eh

I think I'd be selling it soon after that repair :unsure:
 

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That looks like nikasil treated aluminum cylinders but just from looking. An option is searching ebay for cylinders and pistons in better shape, a set from the same bike. FWIW. Best of luck.
 

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You're looking at $500 for nikasil replating plus a set of rings. On the bright side the rod journals looks good. This damage may be from running no air filter, I would expect scoring on the crankshaft if debris in the oil. You can lightly polish the skirts and run those pistons or even coat them at home with graphite coating that you apply with a brush or airbrush and bake in the oven, I have gone this route with success.

 

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Discussion Starter · #11 ·

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Discussion Starter · #12 ·
How many miles are on the engine?
Measuring the cylinder bore with a dial bore gauge and micrometer, then the pistons with a micrometer is the only way to know how much wear you have. (Piston to cylinder bore clearance).

S F
last time I checked it was around 50k KMs I think that is around 31k miles. I am measuring the pistons and cylinders now, so far they seem to be within the range
 

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Discussion Starter · #14 ·
You're looking at $500 for nikasil replating plus a set of rings. On the bright side the rod journals looks good. This damage may be from running no air filter, I would expect scoring on the crankshaft if debris in the oil. You can lightly polish the skirts and run those pistons or even coat them at home with graphite coating that you apply with a brush or airbrush and bake in the oven, I have gone this route with success.

thanks, I will search for the same version around here
 

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I would take the cylinder block and pistons to a machine shop that works on engines. They can figure out how much material needs to be removed, and if the piston to bore fit is acceptable. What about the crank bearings or bushings? UK
 

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Discussion Starter · #16 ·
I would take the cylinder block and pistons to a machine shop that works on engines. They can figure out how much material needs to be removed, and if the piston to bore fit is acceptable. What about the crank bearings or bushings? UK
makes sense. thank you!
 

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Discussion Starter · #17 ·
That looks like nikasil treated aluminum cylinders but just from looking. An option is searching ebay for cylinders and pistons in better shape, a set from the same bike. FWIW. Best of luck.
I have been searching and it seems it could also be "Alusil" ? do you know if there is any way to differentiate one from the other?
 

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thanks, it is a 2006 so I think the engine is different. as in, there is no block for cylinders only. what I am seeing is that half the engine is one single block.
Wow you're really short on options then with a one piece upper case and block. If all the bearings and crankshaft journals look good then having the cylinders repaired with new rings is one path, a complete used engine is another, and just parting the bike out and getting another is a third. Here is the piston skirt coating I mentioned. It's too thin to fill in the scratches but does reduce friction.


If you're not experienced in engine work swapping it out or buying another bike may be the way to go. Your choice though if you want to tackle it.
 

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Scratches on cylinder walls matter. A lot. Mild scratches on piston skirts alone don't matter so much. IMO and experience.
 

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You're not going to be able to just hone those scratches out, your oil had dirt in it.
I gave him advice Carny Gisada, I said he's not going to be able to hone out those scores in the cylinder wall.
And the post you read as me being sarcastic to the OP was not even directed to him, it was to this post:

How many miles are on the engine?
Measuring the cylinder bore with a dial bore gauge and micrometer, then the pistons with a micrometer is the only way to know how much wear you have. (Piston to cylinder bore clearance).

S F
Scores in the cylinder wall can not be measured with a dial bore gauge or micrometer.

... and ya, scores on the lower piston skirt don't matter much considering the skirt is never suppose to come in contact with the cylinder wall, the rings do. The scores are there because of chunks of dirt or metal that were greater in size then the piston skirt to cylinder wall clearance.
 
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