Drilling piston oil holes.

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Fletch 2
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Drilling piston oil holes.

Post by Fletch 2 »

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.
HrcRacing
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Post by HrcRacing »

Wiseco link below. Click on the "M-Series Piston Installation" link.

http://www.wiseco.com/InstallationManuals.aspx
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AlisoBob
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Post by AlisoBob »

The size and position of the holes isnt super critical.

Getting them centered on the bridge is...

Take you time.
bigpower
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Post by bigpower »

AlisoBob wrote:The size and position of the holes isnt super critical.

Getting them centered on the bridge is...

Take you time.
I like to drill 'em about .100 (2.5mm).

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
Kalkaska, the inbred capital of Michigan. ....a place you can walk into the greeting card aisle and find one that reads "Happy Birthday Uncle Dad"
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AlisoBob
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Post by AlisoBob »

Yup, listen to AJ....

:wink:
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iggys-amsoil
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Post by iggys-amsoil »

I don't run the holes.

However the instructions say .300 from the bottom ring and holes to be .060-.090. :shock:
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redrocket190
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Post by redrocket190 »

...then your exhaust port bridge is relieved. The holes lubricate the un-releived bridge, keep it cool and stop it pinching the piston. For all the wrong reasons I can confirm an unrelieved bridge plus no holes is worth about 1/2 lap of the Elsinore GP. :oops:
Michael Stiles
2007 Honda CR500R-AF
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M.F.D.B.
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Post by M.F.D.B. »

iggys-amsoil wrote:I don't run the holes.

However the instructions say .300 from the bottom ring and holes to be .060-.090. :shock:
Dude, if you think 90 thou is big, look at Glens pistons... :wink:
Faster then Speedy Gonzalez, slower then the Road Runner!!! MEEP MEEP

2002 CR80
1999 Cr500
2003 CR250R
2005 CRF250R
2006 YZ450F
2005 CBR1000RR
1997 Banshee
fastkart
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Post by fastkart »

Last edited by fastkart on September 10th, 2008, 9:04 pm, edited 1 time in total.
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M.F.D.B.
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Post by M.F.D.B. »

fastkart wrote:Yep... heres some pics

http://www.bannedcr500riders.com/board/ ... g&start=27
:wink:
Faster then Speedy Gonzalez, slower then the Road Runner!!! MEEP MEEP

2002 CR80
1999 Cr500
2003 CR250R
2005 CRF250R
2006 YZ450F
2005 CBR1000RR
1997 Banshee
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iggys-amsoil
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Post by iggys-amsoil »

M.F.D.B. wrote:
iggys-amsoil wrote:I don't run the holes.

However the instructions say .300 from the bottom ring and holes to be .060-.090. :shock:
Dude, if you think 90 thou is big, look at Glens pistons... :wink:
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.
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M.F.D.B.
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Post by M.F.D.B. »

iggys-amsoil wrote: I still think its over kill, but I'm not even going to question the man.
Better not!! :wink:
Faster then Speedy Gonzalez, slower then the Road Runner!!! MEEP MEEP

2002 CR80
1999 Cr500
2003 CR250R
2005 CRF250R
2006 YZ450F
2005 CBR1000RR
1997 Banshee
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4Z
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Post by 4Z »

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?
fastkart
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Post by fastkart »

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 small holes are for the same purpose as the one on the bridge. To get more oil to the cylinder wall.

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.
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lewisclan
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Post by lewisclan »

oil.......
Image"the game of life of is not so much in holding a good hand as playing a poor hand well"
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britincali
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Post by britincali »

Intake.
Coolness list by 90cr500guy

Bob's = 50/50
Cepek = cool
Solidbro = cool
Brit = loser
Stoffer = 1 up from Brit
MFDB = cool
Danny = ok
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