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Old 11-04-2010, 02:08 AM   #16
Padmei
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Quote:
Originally Posted by supershaft


The rings look like they have sealed real well from the looks of the piston crowns.
What would it look like if the rings hadn't sealed? Pitted?

I would only clean off the piled up and caked carbon.

What with? Green scouring pads?

IMO, the rings won't be worn but the top side of the top ring groove might be. Anything you can do about that? Is it a critical issue?


Sorry for the hijack Bikecat
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Old 11-04-2010, 09:43 AM   #17
supershaft
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Good sealing rings will have uniform, dry carbon on the piston crown all the way to the edge and all the way around. A lot of pretty good sealing pistons have a little oil wash on the bottom.

I use mostly chop sticks. I will very carefully use a wide bladed Exacto knife on a stubborn chunk. I don't use scouring pads. There is no need to remove the thin layer of carbon, just the cake.

The only way to deal with worn ring grooves is to get new pistons. It's critical if you want to fix it. Rings seal on the cylinder wall but they also seal on the piston. A lot of people forget this fact.
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Old 11-04-2010, 11:35 AM   #18
Padmei
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Thanks SS


Chop sticks? Let me guess - the closest thing you had lying around
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Old 11-04-2010, 12:22 PM   #19
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I've heard letting some Sea Foam soak into caked on carbon deposits will make removing them easier.
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Old 11-04-2010, 12:42 PM   #20
supershaft
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Quote:
Originally Posted by Padmei
Thanks SS


Chop sticks? Let me guess - the closest thing you had lying around
No. I actually buy them specifically for shop use. I get good ones and sharpen them into this or that shape for this or that use. Wood is softer than metal!
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Old 11-07-2010, 01:06 AM   #21
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Quote:
Originally Posted by Padmei
Sorry for the hijack Bikecat
No problem; we're all learning here, and I am grateful for the knowledge and information imparted.

Things took an interesting turn when I worked on the bike. I removed the valves with the help of a valve-spring compression tool:





The valves were not wearing evenly; any idea what would cause this?





Started cleaning the cylinders ...



I've learnt that it is important not to mix up the left / right sides; critical to label them properly. Take things slowly is important; almost like a zen approach. Next thing I did was to clean the pistons ......... that's where it got interesting .....

Cheers
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Old 11-07-2010, 04:28 AM   #22
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Originally Posted by bikecat
I've learnt that it is important not to mix up the left / right sides; critical to label them properly. Take things slowly is important; almost like a zen approach. Next thing I did was to clean the pistons ......... that's where it got interesting
Is it possible to mix them up? The spark plug hole would be on the wrong side.
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Old 11-07-2010, 09:31 AM   #23
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Originally Posted by Jasper ST4
Is it possible to mix them up? The spark plug hole would be on the wrong side.
Not likely that you'd get the heads confused but it's probably not a bad idea to mark the cylinders, etc. to keep parts together.
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Old 11-07-2010, 09:37 AM   #24
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Quote:
Originally Posted by fishkens
Not likely that you'd get the heads confused but it's probably not a bad idea to mark the cylinders, etc. to keep parts together.


It's actually impossible to mix them up.
The intakes and exhaust spigots are not concentric, they would point off in odd directions.
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Old 11-07-2010, 11:01 AM   #25
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It's actually impossible to mix them up.
The intakes and exhaust spigots are not concentric, they would point off in odd directions.
Exactly why it's not likely. That and the fact that the push rod holes would've gone all /2 on you ifn ya tried to point the intake/exhust in the right direction.
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Old 11-07-2010, 11:25 AM   #26
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It looks to me like that one valve wasn't closing. You can see carbon all over the face of the valve seat, which should never, ever be there. I assume you were having compression issues on that cylinder?

Your real task here is to figure out what's up with that valve. Was it left too tight during an adjustment?
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Old 11-07-2010, 04:49 PM   #27
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Thanks for the replies. This is the first time that I took apart the cylinders so I am careful not to mix up both sides (noob here); I am sure that with experience it will be easy to differentiate the two sides. I also read up and it seems that the rocker arms and valves are not interchangeable left/right sides. Great pointers from all.

The valves will be re-seated and I've sent them to a machinist to get that done.

Meanwhile, I did some work on the pistons. Kinda got carried away on the left one:



It seems that there is some markings of engine capacity / piston direction on the piston's surface. There's also something that looks like a "$" sign?



Right one:





The right one has an interesting pattern of wear, anything I should be concerned about?





When I was cleaning the right piston, I found this ....



So an order is out for a new set of rings. Looks like it's more than just pushrod seal replacement :)

Cheers
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Old 11-07-2010, 05:16 PM   #28
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Quote:
When I was cleaning the right piston, I found this ....
fantastic
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Old 11-07-2010, 05:26 PM   #29
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The arrows go forward obviously, the dollar signs are for if you eff it up. That wear is interesting, wonder if it's related to the busted ring?
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Old 11-07-2010, 05:41 PM   #30
supershaft
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I guess that busted ring didn't gouge the bore? I would be sure and check the ring groove. New rings don't help much with wallered out ring grooves and it's that top groove that often wears. It's always the top side of the groove. You can see the wear if you look closely. If you run a feeler gauge all the way to the bottom of the groove you won't measure any wear because the bottom of the groove doesn't wear. It only wears higher up where the ring is.

I have seen a lot of nasty looking and even hammered in exhaust seats still seal perfectly but they still needed attention. I wouldn't be surprised if those exhaust guides are looser than a goose.
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