| | Weird stripes inside the cylinder |  |
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Maverock
Nombre de messages : 24
Localisation : Italy
Date d'inscription : 18/11/2013
| Sujet: Weird stripes inside the cylinder  Mer 28 Sep 2016 - 13:16 | |
| Hello, since here it's full of experts, I'd like to ask you what could have caused in your opinion these stripes (especially the horizonthal ones) in this cylinder: [Vous devez être inscrit et connecté pour voir cette image]The cylinder has about 500 hours, 100 hours from the last "clean up" (after which only the vertical stripes were present, the horizonthal ones are a new of now), it still has its full 180psi of pressure after 100 hours with the new piston and runs great. The dark stripes are NOT wet, like oil you can remove from your finger, and they can't be felt neither with the nail, i.e. it's smooth and dry. Thank you very much for your insights. With kind regards, Tony |
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Maverock
Nombre de messages : 24
Localisation : Italy
Date d'inscription : 18/11/2013
| | Sujet: Re: Weird stripes inside the cylinder Mer 28 Sep 2016 - 13:33 | |
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Dan42
Nombre de messages : 8648
Localisation : Margerie-Chantagret 42
Date d'inscription : 06/04/2014
| | Sujet: Re: Weird stripes inside the cylinder Mer 28 Sep 2016 - 13:52 | |
| The vertical ones are directly on the wall parts of the cylinder, between ports. Carbon deposit, coming whith oil mix?
Dan |
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Phytus
Nombre de messages : 646
Localisation : Monségur
Date d'inscription : 22/06/2012
| | Sujet: Re: Weird stripes inside the cylinder Mer 28 Sep 2016 - 14:19 | |
| Stripes mades by the machinihg before the nikasil treatment? Ring rebound?!  |
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marcolemotard
Nombre de messages : 439
Age : 37
Localisation : la Rochelle / Quebec
Date d'inscription : 08/12/2012
| | Sujet: Re: Weird stripes inside the cylinder Mer 28 Sep 2016 - 21:10 | |
| It looks helicoidal. I would say like Phytus: because of the machining.
It may be very low, less than one micron, but you still see it. |
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Maverock
Nombre de messages : 24
Localisation : Italy
Date d'inscription : 18/11/2013
| | Sujet: Re: Weird stripes inside the cylinder Jeu 29 Sep 2016 - 10:41 | |
| But they weren't visible before. Perhaps the latest treatment (100 hours ago) to polish the cylinder may have induced it?
Should I worry? It runs perfectly but, does it impede for example to the oil to adhere well to the cylinder wall?
PS: and what about the uppermost part of the cylinder, with that brown-copper discoloration, i.e. where the rings never come? What do you think? |
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lvs
Nombre de messages : 9
Age : 64
Localisation : nederland
Date d'inscription : 08/01/2011
| | Sujet: Re: Weird stripes inside the cylinder Lun 3 Oct 2016 - 13:52 | |
| it like that the nicasil is gone .
on top its white ... the color off the naked cilinder .
## |
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fullgazlolo
Nombre de messages : 1832
Localisation : GE-CH
Date d'inscription : 04/01/2016
| | Sujet: Re: Weird stripes inside the cylinder Lun 3 Oct 2016 - 15:00 | |
| 1) défaut de planéité de culasse/cylindre ou les 2
2) c'est usé à la moelle: y a plus aucune trace de rodage sur le cylindre
3) à part remesurer le cylindre pour voir ce qu'on peut en faire... |
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Mikey Antonakakis
Nombre de messages : 24
Localisation : Colorado Springs, CO, USA
Date d'inscription : 05/06/2014
| | Sujet: Re: Weird stripes inside the cylinder Jeu 23 Nov 2017 - 1:20 | |
| - lvs a écrit:
- it like that the nicasil is gone .
on top its white ... the color off the naked cilinder .
## I agree, I had a 50cc Polini cylinder where this happened, it looked exactly the same (but mine was much more worn! Engine still ran strong). I am only referring to the top section of the bore - the horizontal stripes look similar, but it's more difficult to say. |
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Invité
Invité
| | Sujet: Re: Weird stripes inside the cylinder Jeu 23 Nov 2017 - 11:11 | |
| strange I have never seen this  good luck  |
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