Is this normal? (piston)

J

Joe_148

Member

Mar 13, 2004

54

0

• May 17, 2004

• #1

This is the piston that just came out of my bike. You can very slightly feel the scratching ont he side of the piston. Its on the side of the exhaust manifold. To the eyes and to touch the cylinder wall, I could feel no scoring or scratches. Ihave the new piston and everything already installed in the bike and im just waiting for a power valve gasket to fire it up. Is this scratching normal? The last time I rode it was colder than usual, but the plug reading was still dark brown? Also is this burn pattern ok?

http://www.photodump.com/direct/Joe_148/piston1.jpg

http://www.photodump.com/direct/Joe_148/piston2.jpg

 

S

showtime586

Member

Mar 28, 2004

512

0

• May 17, 2004

• #2

I'm thinking that the only contact with the cylinder wall should have been with the piston ring, and not the piston.
You might try a flapper wheel to see if you can smooth out any burs you feel in the cylinder.

 

RM_guy

Moderator

Damn Yankees

LIFETIME SPONSOR

Nov 21, 2000

7,045

208

North East USA

• May 18, 2004

• #3

Looks like you had some seizing going on. As long as the cylinder wall wasn't damaged and you have new pistons and rings install you should be OK. DO NOT USE A FLAPPER WHEEL ON THE CYLINDER WALL.

I'd be concerned as to what it wore so bad. Do you let it warm up good enough before riding?

 

L

Layton

~SPONSOR~

Aug 2, 2000

896

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• May 18, 2004

• #4

That piston appears to have lightly seized(sp). Good thing you got a new one.

 

W

WillyM

Member

May 18, 2004

84

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• May 18, 2004

• #5

seized

Yes this piston almost seized, the piston was not evenly warmed when it hit higher rpm. and it scorched the skirt.
You almost locked it up.

 

W

WillyM

Member

May 18, 2004

84

0

• May 18, 2004

• #6

showtime586 said:

I'm thinking that the only contact with the cylinder wall should have been with the piston ring, and not the piston.
You might try a flapper wheel to see if you can smooth out any burs you feel in the cylinder.

Click to expand...

Never use a flapper wheel in a cylinder, use a hone longer than your cylinder.

 

J

Joe_148

Member

Mar 13, 2004

54

0

• May 18, 2004

• Thread starter
• #7

so should the new top end be ok? you think it was just worn out so much that some parts of the piston werent as warm as others?

 

K

kawdude

~SPONSOR~

May 20, 2003

189

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• May 18, 2004

• #8

I would say that it could be related to warm up but I would look to jetting and maybe a unmixed mix...

 

RM_guy

Moderator

Damn Yankees

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Nov 21, 2000

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208

North East USA

• May 19, 2004

• #9

Joe_148 said:

so should the new top end be ok?

Click to expand...

Yes

you think it was just worn out so much that some parts of the piston werent as warm as others?

Click to expand...

You have it backwards. The engine may not have been warmed up good enough and that caused the damage.