What do you think?

C

cr250dave

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Jun 25, 2005

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• Apr 16, 2006

• #1

Has about 20 hours on new piston. I was having what I think is piston slap so I tore it down and saw these marks. The jetting was almost spot on and the wiseco piston was properly broken in and always warmed up before ridden. What do you guys think I should do about this?? I also had a ton of blow by.

 

oldfrt613

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• Apr 16, 2006

• #2

Wiseco reccomends drilling 2 small holes where it rides over the exhaust port bridge, have you done this ?

 

C

cr250dave

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Jun 25, 2005

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• Apr 16, 2006

• Thread starter
• #3

oldfrt613 said:

Wiseco reccomends drilling 2 small holes where it rides over the exhaust port bridge, have you done this ?

Click to expand...

Sure did. It is scuffed around the whole cylinder. While I am still a nub this is my third top end and this is the first time i've seen this :coocoo: What do you recommend I do about the cylinder?

 

oldfrt613

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• Apr 16, 2006

• #4

Is this a stock bore or replated cylinder ?

 

oldfrt613

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• #5

If it has scuffed the whole cylinder, have you checked the ring gap ?

 

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cr250dave

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Jun 25, 2005

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• Apr 16, 2006

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• #6

Stock with a wiseco piston.

 

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cr250dave

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• Apr 16, 2006

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• #7

cr250dave said:

Stock with a wiseco piston.

Click to expand...

old ring gap is.356 mm

 

oldfrt613

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• Apr 16, 2006

• #8

If you can't "feel" any scratches, I'd deglaze it ( 320 grt ball hone ) and and use it. Be sure to check the ring gap. An unpleasant possibility is your lower rod bearing is going out, check it closely. I'd back off on the jetting to start to be on the safe side. You monitor what's going on with the piston without taking the cylinder off by removing the exhaust pipe and looking in the port.

 

oldfrt613

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• Apr 16, 2006

• #9

Wiseco recommends min gap .004"/in on the bore. Stock bore is 2.61" so you should be looking for a gap of .004 x 2.61 or .010" min ( I run my CR at .012" gap ).

 

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cr250dave

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Jun 25, 2005

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• Apr 16, 2006

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• #10

ok will do. thanks for your input

 

oldfrt613

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• Apr 16, 2006

• #11

Always ready to help a fellow red rider ;)