OzVMX Forum

Marque Remarks => Yamaha => Topic started by: vandy010 on November 27, 2008, 02:22:59 pm

Title: YZ125c piston ring question
Post by: vandy010 on November 27, 2008, 02:22:59 pm

ok, so in the parts website, it shows a single ring piston for this model but the engine i'm playing with has a twin ring piston with both bore and piston being very servicable and on 3rd oversize.
my problem is, 
  new rings measure 1.00mm in thickness,  part#2K6-11601-30
      old rings measure 0.6mm in thickness,

inside the piston is cast, 2X301   &    0712     &     ART     &       1/4
with .75 stamped into the crown.
genuine yamaha twin ring piston with cutaway on inlet {i believe}

so what bike is this piston from? and what rings do i need to buy?

thanks in advance guys!

Title: Re: YZ125c piston ring question
Post by: caps 999 on November 27, 2008, 03:04:29 pm

it could be from a yz125 b-f but your prefix matches a yz125f so youll need to order 125f rings

Title: Re: YZ125c piston ring question
Post by: caps 999 on November 27, 2008, 03:06:10 pm

part number is 2x3-11601-30 for 3rd oversize

Title: Re: YZ125c piston ring question
Post by: caps 999 on November 27, 2008, 03:08:18 pm

according to wiseco you can run the same piston for a 76-82 yz125

Title: Re: YZ125c piston ring question
Post by: Nathan S on November 27, 2008, 09:31:18 pm

All of the above is correct.

Yamaha forked around with ring thickness, ring number, cutaway size/shape, etc which makes it harder to get rings off Ebay (or where-ever), but the pistons are all interchangeable (this includes the A and DT/IT125s as well [but remember the YZ-A needs chrome-bore-compatible rings]).
I've got a genuine YZ125N piston here, and I'm yet to find a reason why it wouldn't go into an earlier bike.

Title: Re: YZ125c piston ring question
Post by: caps 999 on November 27, 2008, 09:50:32 pm

i think its got to do with dome height nathan

Title: Re: YZ125c piston ring question
Post by: Nathan S on November 27, 2008, 09:56:08 pm

Yeah, plus the ring locating pins are in a different spot - but (without trying it) it looks as though it will all work fine in an earlier motor.

Title: Re: YZ125c piston ring question
Post by: caps 999 on November 27, 2008, 10:24:22 pm

yes the locating pins and protin may be an issue but you gotta love yamaha r&d change everything but the piston

Title: Re: YZ125c piston ring question
Post by: vandy010 on November 28, 2008, 03:12:04 am

yep! it's bloody confusing,
 cause i believe the #2K6 rings are from the "E" model,
                 while the 2X3 piston is from the "F" model,
 and when i go to the Yammie website,
http://www.yamaha-motor.com/sport/myyamaha/prompt/L3Nwb3J0L3BhcnRzL2hvbWUuYXNweA==/Parts%20Catalog/starthere.aspx
it aludes to the idea they are one and the same. :-\

Title: Re: YZ125c piston ring question
Post by: Nathan S on November 28, 2008, 08:04:05 am

You'll probably find that the E part number has been discontinued, and the F part is the replacement.

Title: Re: YZ125c piston ring question
Post by: caps 999 on November 28, 2008, 08:32:11 am

yes `vandy all the genuine pistons and rings will use differnt genuine part number but you can run any yz125 piston and ring kit in any yz125-76-82