Hi All, I was planning on just doing a ring job but wanted to get collective wisdom of whether this piston looks okay to continue to use. Both rings and piston have 11k kilometers since top end job. My understanding is that theoretically pistons are supposed to be good for 20k of normal street riding (I'm an old fart who does not track the bike - ride moderately sporty at most, e.g., no redlining). So is this blowby pattern sufficiently bad that I should change the piston too. I was hoping to get maybe 8k more but won't wait if it really seems likely to fail. Don't have extra pistons on hand so would have to wait awhile to get back on road, which would be a drag, but will do it if necessary. Thanks for advice.

http://s1221.photobucket.com/user/duclad/media/2014-08-17122350.jpg.html?sort=3&o=0
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-Jim
'93 MC21

doesnt look too bad ,check your tolerances with the manual and if still within what it says just re ring it !
if you had done a compresion test before you had stripped it you would have a good idea if it was still healthy
but for 11000 km they dont look bad at all

That's a really subjective question! Looking at the photo, the piston (well, that side at least!) still looks in pretty good condition.

You want to be checking all around the skirt for any signs of wear, and the crown for any signs of detonation. Dress the ring grooves a little with a stone to prevent the new rings from sticking, and you should be good to go!

Ideally though, you should be measuring the piston(s), not relying on the "verni-eye" gauge/Mk1 eyeball!
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Andy.
NSR-WORLD.COM

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Thanks guys. The other areas of the piston actually look better, no detonation or real signs of wear or blowby, and within spec. The pic is of the only area that was a little bit of concern because of blowby pattern (wasn't sure if that was a function of rings being old or something more worrying), but it sounds like it is likely in good enough shape to continue.

Learning a lot doing this with Scott V.'s help! No shops around here have experience with NSRs so it has kind of forced my marginally mechanical hands to learn to do more. fingers crossed.
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-Jim
'93 MC21

As Andy said....

My biggest concern is asking for Scott V's help. That's a worry.

Matt@TYGA wrote:Scott V's help. That's a worry.

Just kidding

Matt@TYGA wrote:

Matt@TYGA wrote:Scott V's help. That's a worry.

Just kidding

Or are you?!
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Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

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Now, now, guys, go easy on Scott - he's saving my butt and he is willing to do it for beer and "future considerations" on NSR parts once I kick off, or start acting my age and give it up, whichever comes first...can't beat that!
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-Jim
'93 MC21

Matt@TYGA wrote:As Andy said....

My biggest concern is asking for Scott V's help. That's a worry.

And..... I was wondering when that was going to come up!

Was wondering how long it would be before you came along.

Jim, you are acting your age. All others your age are just trying to look mature.

Well, speaking for myself, it is true that I have never put much stock in acting mature. On the other hand, pushing 63 I think I am probably the oldest on the board (there I've confessed my dirty little secret, now no one will "talk" to me) and my aching wrists on the bike and my not quite as sharp mental capacities suggest I am indeed acting my age in some respects at least.
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-Jim
'93 MC21

I'm afraid you're not going to hold that crown! We have someone this side of the pond who pips you!

You should come to our next big Donington day, and the pair of you could tell all us young'uns about what it was like during the war!
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Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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Ha, and so it begins, the elderly jokes. I knew I shouldn't fess up....diminished impulse control, another telltale sign of my advanced age.
_________________
-Jim
'93 MC21

I've decided to stick to larking with those I know have a sense of humour, Jim, so be prepared for more of the same over the course of time!
_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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Thanks for the warning! Fortunately, my failing memory keeps me from holding any grudges, so no worries.
_________________
-Jim
'93 MC21