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Piston identification

07 Jul 2020 04:14
EM ONE
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Piston identification #1
Ive looked all over but cannot find images of the piston i have,its Yamahas own as marked on the inside,and marked on the crown 7 and then a directional arrow then five 180degrees from this its marked 97,and inside its also marked 3 12UMI.Is this oversize as i want to buy some piston rings.Any info appreciated,cheers

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07 Jul 2020 04:38
Gr8uncleal
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Piston identification #2

EM ONE wrote: Ive looked all over but cannot find images of the piston i have,its Yamahas own as marked on the inside,and marked on the crown 7 and then a directional arrow then five 180degrees from this its marked 97,and inside its also marked 3 12UMI.Is this oversize as i want to buy some piston rings.Any info appreciated,cheers


A picture (or two or three!) is worth a thousand words. :likey

Post some and I'm sure that you'll get the info that you need.

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07 Jul 2020 06:53
RT325
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Piston identification #3
Whatever model it is--97 will be the std size.

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07 Jul 2020 11:25
EM ONE
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Piston identification #4
sorry,its an RT 360,73 i belive judging by the frame and engine numbers

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13 Jul 2020 15:29
EM ONE
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Piston identification #5
Just aqquired some standard piston rings,for my piston see image above,and the do not fit,not even nearly.The rings that came off the piston were of two different thicknesses,the ones bought are both two thick for the piston grooves.

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13 Jul 2020 20:04
RT325
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Piston identification #6
Yours is an RT2 or RT3 as i can see the holes in the skirt in the piston pic in your last post. Yamaha in their wisdom use RT1 engine numbers right through from "70 until "73 just to fool us. RT1 had quite thick rings & RT2 &3 have the L shaped 'dykes' top ring if it's a genuine original piston--which it appears to be in the pic. Sorry to tell ya all that. Rings could be a 308 part number but MarkT or someone will put me right on that. Cheers.
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14 Jul 2020 01:07
Swoop56
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Piston identification #7
As RT 325 was saying , the rings you have purchased are RT1 rings . RT2/3 rings are different .
There is a trap there too . There are two different types , which need to match to the piston being used.
The two ring sets are 308-11610-00-00 , and updated set 308-11610-01-00 .
As your bike was still on standard bore ( lucky you ) , the early set SHOULD be what you're looking for ,
as that is probably the original piston .
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14 Jul 2020 11:34
EM ONE
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Piston identification #8
Yes my Rt1 is a Rt3 1973 model,cheers for the info guys,appreciated.Let the build commence

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04 Aug 2020 09:50
EM ONE
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Piston identification #9
Ive been lookng for a while now,but i cannot get any of the piston rings 308-11610-00-00 for my bike here in the UK.I was wondering if an earlier standard piston would fit.as the rings and pistons seem to be more plentiful.Also will it be the same wrist pin/little end.Cheers in advance

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04 Aug 2020 15:15
RT325
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Piston identification #10
Everything in the 360's are pretty interchangable but so long as the earlier piston you're talking has the reed inlet holes in the skirt. gudgeon size & all that is the same, bearing etc. I thought all the reed 360's had the L shape top ring from "72 reed models but might be wrong. Actualy--don't tell anyone, but i've used an RT1 piston in one of mine "needs must" & i didn't have an RT2 piston kit. I just cut a hole high up in the shirt but would still have worked without holes if ya desperate but performance would be compromised. Piston port 360 gudgeon height & all that are the same. 250's change the gudgeon height from DT1 to DT2 & 3.

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