Drilling piston oil holes.
Drilling piston oil holes.
When drilling those oil holes in the piston, how far below the lower ring should the first hole be drilled, how many and the distance between them? Also what size should they be drilled out to?
Thanks.
Thanks.
Wiseco link below. Click on the "M-Series Piston Installation" link.
http://www.wiseco.com/InstallationManuals.aspx
http://www.wiseco.com/InstallationManuals.aspx
I like to drill 'em about .100 (2.5mm).AlisoBob wrote:The size and position of the holes isnt super critical.
Getting them centered on the bridge is...
Take you time.
Make sure you remove the burrs from the inside of the piston when finished.
Another thing that I like to do thats an old school procedure is take you some 320 grit paper , and lightly chamfer all the sharp edges on the piston skirt. Alot easier on the break in
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- iggys-amsoil
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- redrocket190
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Dude, if you think 90 thou is big, look at Glens pistons...iggys-amsoil wrote:I don't run the holes.
However the instructions say .300 from the bottom ring and holes to be .060-.090.
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2002 CR80
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2002 CR80
1999 Cr500
2003 CR250R
2005 CRF250R
2006 YZ450F
2005 CBR1000RR
1997 Banshee
Last edited by fastkart on September 10th, 2008, 9:04 pm, edited 1 time in total.
- iggys-amsoil
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I saw those, and considering the application I see why. I still think its over kill, but I'm not even going to question the man.M.F.D.B. wrote:Dude, if you think 90 thou is big, look at Glens pistons...iggys-amsoil wrote:I don't run the holes.
However the instructions say .300 from the bottom ring and holes to be .060-.090.
The small holes are for the same purpose as the one on the bridge. To get more oil to the cylinder wall.4Z wrote:Ok, I get the idea behind the holes for exh bridge, but in Brit's pics, what are the rest of them intended for, mainly the large one?
The big one, Glen told me, is basically an extra intake hole. I see it as a way to get more oil to the small end bearing. He told me if I didn't have that hole cut on a replacement top end, I'd lose some power.
- britincali
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