01-23-2018, 09:32 PM | #31 |
Join Date: Apr 2017
Location: Omaha, NE
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The problem with checking the ends of the cylinder is that most oblong wear tends to happen more in the center of the bore. I knew the chance of it being out of round was minimal given the lack of miles on the motor, but the debris scuffing on the cylinder walls was pretty severe. I agree with Jerry about honing it a bit more until those vertical scratches are gone. They aren't very deep looking, so your piston clearances should still be ok. They are usually loose on an aircooled engine anyway.
As far as the piston, yes, that is a good way to check them for any taper wear. I would definitely take the time to clean the heck out of that cylinder. I usually clean with warm soapy water, and then wipe down with clean rags and WD-40 until I get nothing to wipe off on the rag anymore. Then coat the cylinders with a thin coat of assembly lube (it sticks better). This would be a good chance to try and flush out the crankcase and clear the centrifugal oil filter as well. Might as well start with as clean of an engine as you can.
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01-30-2018, 11:44 AM | #33 |
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Looks pretty good. But me being OCD I would do it a little more to get rid of that last bit of gasket ring mark.
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01-30-2018, 02:04 PM | #34 |
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X2. It shouldn't take much more to get rid of that last ring mark on the head surface.
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01-30-2018, 02:49 PM | #35 |
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Location: connecticut
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For my education, can you point out the residual gasket ring mark? TY.
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01-30-2018, 02:59 PM | #37 |
Join Date: Jan 2018
Posts: 43
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I went ahead and took care of that gasket residue. I just got the piston and rings in today as well. Went ahead to gap the rings and at both top and bottom I was getting a ring gap of .016 inch which from what I read about ring gap should be acceptable. Does that sound to be okay?
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01-30-2018, 03:53 PM | #38 |
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Looks good to me. The cg125-150 specs are.
First ring = .15 to .35mm Second ring = .15 to .30mm Oil rings = .20 to .50mm
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01-30-2018, 07:42 PM | #39 |
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So my first ring is .016in (.40mm) should be okay? It's .05mm out of spec
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01-30-2018, 08:08 PM | #40 |
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Basics: http://www.dansmc.com/pistons.htm
1 of the 67mm application (LY200 is a Yamaha clone / most CG250 also use same size rings http://www.anerda.com/html/ProList.a...=0,283,&Page=9) :
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Last edited by humanbeing; 04-12-2018 at 09:11 PM. |
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01-30-2018, 08:46 PM | #41 | |
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Quote:
As humanbeing stated, the other option is to use another 67mm bore aircooled engine as an analog.
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01-31-2018, 12:35 PM | #42 |
Join Date: Jan 2018
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Went ahead and cleaned the cylinder and head, installed the piston into the cylinder with assembly lube and was going to torque down the bolts and I wasn't sure how much to torque them down to? Found a service manual for the cg 125/150 and it says 21-25 nm
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01-31-2018, 01:13 PM | #43 | |
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Quote:
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01-31-2018, 01:35 PM | #44 |
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Again, this. Just make sure to stage it in at least 2 steps and tighten in a cross cross pattern like you would a 4 lug car wheel.
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01-31-2018, 03:10 PM | #45 |
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After I torqued all the bolts down im getting 200 psi compression. Could it be so high from the assembly lube?
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