Author Topic: YZ piston  (Read 2415 times)

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Offline Rossvickicampbell

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YZ piston
« on: August 01, 2016, 12:09:41 pm »
Gents - what piston do I have here please?  Sorry - computer problems with loading photos so cannot post direct.

ta

http://i950.photobucket.com/albums/ad349/rossvickicampbell/YZ%20piston_zpscrdknivm.jpg
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline pokey

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Re: YZ piston
« Reply #1 on: August 01, 2016, 04:56:31 pm »

Offline pokey

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Re: YZ piston
« Reply #2 on: August 01, 2016, 05:07:52 pm »
Its yamaha soo its a size. 61.958 i believe, what it fits apart from a 125cc is more than this yellow brain can work out.

Offline Rossvickicampbell

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Re: YZ piston
« Reply #3 on: August 01, 2016, 05:20:25 pm »
thanks for posting the pic Pokey - and sorry - should of mentioned - it is out of a YZ250A - but not sure on size or type ie is it DT, YZ or MX etc.
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline pokey

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Re: YZ piston
« Reply #4 on: August 01, 2016, 05:52:52 pm »
Sheesh now that dont make sense. the 185 uses a 64mm . most 125s are 61, i think even the honda 750-4 uses a 61 i think.
 why would you put those numbers on if it wasnt a size?
 im sure Ive read  someplace (wossner or wiseco) about the size being written that way in two parts.  Good luck and I will check on the answer as Im intrigued.

Offline Nathan S

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Re: YZ piston
« Reply #5 on: August 01, 2016, 06:16:36 pm »
Yamaha 125s were 56mm in ye olde dayes.
54mm for newer stuff (94+).

Ye olde 175s were 66mm.

Photos from the sides would help. From memory:
Anything with a dykes top ring is DT.
Anything with a cut-away intake skirt (as opposed to holes) is YZ.
Anything with little circular intake holes is DT.
« Last Edit: August 01, 2016, 06:20:54 pm by Nathan S »
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Offline micko

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Re: YZ piston
« Reply #6 on: August 01, 2016, 06:23:13 pm »
Rosco posted for me, (thanks mate) my plastic verniers say 70mm and its YZ250A.
Inside the skirt says 4310 also says ART and a dot two slashes and a 2 (maybe 2nd over)
RM370A RM250A RM125A RM125S YZ250A YZ125C XR75K4

Offline micko

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Re: YZ piston
« Reply #7 on: August 01, 2016, 06:24:25 pm »
yes has a cutaway nathan
RM370A RM250A RM125A RM125S YZ250A YZ125C XR75K4