Howser

Member
Jun 1, 2010
10
0
i need to know if my 1993 yz 125 has a nikasil bore or not? just pretty much got the bike and its time for a piston. someone has put a wiseco in it that is believe is stock bore size at 56mm and id like to go 1 size over at 56.5mm(.020").
 
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RM_guy

Moderator
Damn Yankees
LIFETIME SPONSOR
Nov 21, 2000
7,045
208
North East USA
If it's stock then it's plated. If someone installed a sleeve then it's not plated. A magnet will stick to a sleeve but not to plating.
 

Howser

Member
Jun 1, 2010
10
0
can anyone tell me what the wiseco piston to cylinder clearance suppost to be? if i can get about with not replating/boring it id like to..
 

helio lucas

~SPONSOR~
Jun 20, 2007
1,020
0
one time i had asked a question like that. i got thins answer:
"the maker of the piston knows better than i and they already make the piston with the correct clearance. if you measure a piston you will note that for a 46mm bore the piston is some 0.05 mm smaller, so i just bore it to 46mm."

on the service manual you have the correct clearance. check out wiseco website on the link:
http://www.wiseco.com/FAQs.aspx

if you want to go bigger then the cylinder must be bored and/or replated.
 
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eagles22793

Member
May 25, 2008
146
0
the nikasil is a must i have a 2000 yz125 and wanted to do a big bore kit but it cost to much for the nikasil and wanted to leave it out but you cant the piston will melt to the side of the cylinder because the cylinder is not made of strong enough aluminum to handle the heat
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
To get the cylinder re-plated, or go for an over bore and re-plated, should be the same price. Except real big, that may need case mods also? Contact Forward Motion, and Eric Gorr, if you go that route.
 

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