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Cylinder transfer clean-up final go.

Spoon Carving With Tom

Spoon Carving With Tom

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id imagine I have spent over 2 & 1/2 hours sanding this cylinder of the aluminium transfer and damage. I started at 240 until everything was clean and worked up to 1200 grit.

Here is a video, watch it in HD



The cylinder is smooth without feeling any ridges or anything. In one of the pictures you can see what look like bad vertical lines, but they are perfectly smooth and aren’t ridges or valleys, you can’t feel anything with your fingers. I really don’t know, but what do you think?

I also used polishing compound and a felt wheel on a dremel to remove the carbon in the exhaust port (NOT THE CYLINDER) followed by 600 grit sandpaper to get the stubborn stuff. It took quite some time but came up nice!

Would you be happy putting this in your saw?

A4180D42-010F-4546-A0AC-1D5BE6119D74.jpeg 33832029-7AC7-4E1E-8C02-22C8BA38E56F.jpeg AC3B71C5-C9CB-424E-A8D0-D910557B6384.jpeg 9C35D6F4-5269-47F3-A285-DEBADED02115.jpeg
 

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holeycow

holeycow

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The purpose of cleaning the cylinder is to remove all aluminum transfer (melted piston material) and glazing from the original factory cross-hatching. The cross-hatching is the final cylinder finish which is put there to continuously retain oil on the cylinder wall, as well as break-in the ring.

This is how I understand it anyway.

It is hard to tell from the pictures if you have exposed and retained the cross-hatching or not. I fear you have actually polished the cylinder. The new ring may not seat effectively.

You could give it a go. If you try, and because the bottom end is already broke-in, don't dilly-dally on break-in. Run that thing like you stole it as soon as the motor is warmed up good. Bury the bar and work it hard! That may work.

I might be inclined to get a three-finger hone and hone that cylinder. This is usually not necessary, and normally required only on iron bores.

I've done lots of modern dirt-bike top-ends using only scotch-brite pads and wd40, followed by soap (like dish-soap that doesn't leave a film) and water and then just water.

There is an argument for breaking top-ends in dry, not oiled in order to ensure a good ring seal. That method might be tempting in your case.

Anyway, there will be other opinions to come..

I looked again, the crosshatching may be exposed in places. Good! Get some scotchbrite and wd40 and scrub the **** out of that puppy! Get rid of that polishing compound.
 
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Bob Hedgecutter

Bob Hedgecutter

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Almost looks to be too spit polished........ well a damn sight more than my usual near enough is good enough rebuilds. I would have been happy enough to put it back together with your last post on the same cylinder- as long as there were no fingernail catching nicks, ridges or gouges.
Computer photos are always hard to call though, much different to having the piece in hand and being able to tilt it to catch differing light.
I guess if the rings don't bed in, you could always use it for a shaving mirror? ;)
 
Spoon Carving With Tom

Spoon Carving With Tom

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The purpose of cleaning the cylinder is to remove all aluminum transfer (melted piston material) and glazing from the original factory cross-hatching. The cross-hatching is the final cylinder finish which is put there to continuously retain oil on the cylinder wall, as well as break-in the ring.

This is how I understand it anyway.

It is hard to tell from the pictures if you have exposed and retained the cross-hatching or not. I fear you have actually polished the cylinder. The new ring may not seat effectively.

You could give it a go. If you try, and because the bottom end is already broke-in, don't dilly-dally on break-in. Run that thing like you stole it as soon as the motor is warmed up good. Bury the bar and work it hard! That may work.

I might be inclined to get a three-finger hone and hone that cylinder. This is usually not necessary, and normally required only on iron bores.

I've done lots of modern dirt-bike top-ends using only scotch-brite pads and wd40, followed by soap (like dish-soap that doesn't leave a film) and water and then just water.

There is an argument for breaking top-ends in dry, not oiled in order to ensure a good ring seal. That method might be tempting in your case.

Anyway, there will be other opinions to come..

I looked again, the crosshatching may be exposed in places. Good! Get some scotchbrite and wd40 and scrub the **** out of that puppy! Get rid of that polishing compound.
Hey mate :) thanks for the post. Hmm, maybe o should have the shop check the jug. Just to reiterate there is no polishing compound in the cylinder! I just used it in the exhaust outlet to remove the carbon. Just abrasive paper inside this cylinder.
 
Spoon Carving With Tom

Spoon Carving With Tom

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Almost looks to be too spit polished........ well a damn sight more than my usual near enough is good enough rebuilds. I would have been happy enough to put it back together with your last post on the same cylinder- as long as there were no fingernail catching nicks, ridges or gouges.
Computer photos are always hard to call though, much different to having the piece in hand and being able to tilt it to catch differing light.
I guess if the rings don't bed in, you could always use it for a shaving mirror? ;)
Lol thanks Bob i’m Going to take a video for you guys!
 
holeycow

holeycow

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I'm dizzy! Hold still! Ha!

That looks good. I think. It's hard to tell for sure in pics. It will certainly work. Work optimally? That's hard to say without seeing it in person.

Make sure the glaze is gone everywhere and put'er together. Break it in hard after thorough warmup, like I said. And like jethro said.
 
Spoon Carving With Tom

Spoon Carving With Tom

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I'm dizzy! Hold still! Ha!

That looks good. I think. It's hard to tell for sure in pics. It will certainly work. Work optimally? That's hard to say without seeing it in person.

Make sure the glaze is gone everywhere and put'er together. Break it in hard after thorough warmup, like I said. And like jethro said.
Oh ha sorry mate and thanks for your advice, here is a still shot :)

As for the top end bearing, current one feels and looks solid. No wiggle or wear apparent, do you change them as a matter of caution regardless?
81098B5B-3596-4EB8-99CC-D6659E31F3AB.jpeg
 
holeycow

holeycow

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Ok. Pour some mix into the crank-case and roll the crank around with the rod. Gently at first a bunch of times. Feel for "catches". If you feel anything, don't force it through, reverse it and slowly try to work out the piece.

Slosh that around and around a bit to make sure the crankcase is clean and no grit is present. Dump and repeat until you are satisfied that what you are going to assemble is meticulously clean.

Put some drops of oil on both rod bearings. Start putting it together. Woohoo! You decide if you want to slip the piston into a dry cylinder or not. I oil lightly, but there is a solid argument for dry assembly (maximum ring seal). It will only be dry for a very short time..
 
Spoon Carving With Tom

Spoon Carving With Tom

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Ok. Pour some mix into the crank-case and roll the crank around with the rod. Gently at first a bunch of times. Feel for "catches". If you feel anything, don't force it through, reverse it and slowly try to work out the piece.

Slosh that around and around a bit to make sure the crankcase is clean and no grit is present. Dump and repeat until you are satisfied that what you are going to assemble is meticulously clean.

Put some drops of oil on both rod bearings. Start putting it together. Woohoo! You decide if you want to slip the piston into a dry cylinder or not. I oil lightly, but there is a solid argument for dry assembly (maximum ring seal). It will only be dry for a very short time..
Thanks so much for writing all that mate :) this saw is actually currently in bits, I took it all apart to bring from the Uk to australi. Every part has been cleaned, degreased and dried and then bearings, chain etc have had a light coat of oil. I’m waiting for a bunch of new things including fuel ines/ oil hoses, o-rings etc to arrive this coming week and my metor piston too :)
The saw is my fathers, about 20 years old (ms 260 pro) but he only used it once or twice a year max for about 2-5 hours each time and only had a 16” bar so it’s not been pushed to its max, so although it’s old, for a pro saw it’s had next to no hard use, hence the question of the bearing replacement even if it feels good?

68FBDCB4-0DCC-47CD-85BB-1E25EF2AB1F1.jpeg
 
holeycow

holeycow

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Wrist pin bearings are cheap. I change them. Just like I change circlips.

Put your circlip opening to the top or the bottom. Be careful not to get one in the eye when it springs out! Be patient with the little buggers. On a bad day they can be the toughest part of the whole rebuild. Put one in the piston before assembly. Whichever side suits you. The clips have to be seated perfectly in the groove. Check that by rotating them with a small screwdriver (to orient the opening top or bottom). If they won't spin, they aren't in.
 
holeycow

holeycow

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I've been following along with your story. Good story!

look at that bearing with a high power magnifying glass in good light. Look for any loss of plating on the cage, any scratches on the needles, any hairline cracks in the cage (usually stress cracks found at the ends of the needles in the cage at the corners). If you get a bearing, buy oem from the saw shop.

I replace them anyway. Every 20 hours in small bore dirt bikes in the day. I was too cheap to do top ends every 10 hours in 125's, but that would be ideal. I don't know why those wrist pin bearings don't come in the kits.
 
Spoon Carving With Tom

Spoon Carving With Tom

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Wrist pin bearings are cheap. I change them. Just like I change circlips.

Put your circlip opening to the top or the bottom. Be careful not to get one in the eye when it springs out! Be patient with the little buggers. On a bad day they can be the toughest part of the whole rebuild. Put one in the piston before assembly. Whichever side suits you. The clips have to be seated perfectly in the groove. Check that by rotating them with a small screwdriver (to orient the opening top or bottom). If they won't spin, they aren't in.
Excellent advice mate, thanks!

Yes I have heard about the problems c-clips can cause and to orientate them correctly!! I have ordered OEM ones, I know my metor piston comes with them but they have ears and I was warned about them and how they can spring open!

I was also told of a great way to put them in but will have to re-read the post if I can find it!

Thanks for sharing the info you have :)
 
Spoon Carving With Tom

Spoon Carving With Tom

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I've been following along with your story. Good story!

look at that bearing with a high power magnifying glass in good light. Look for any loss off plating on the cage, any scratches on the needles, any hairline cracks in the cage (usually stress cracks found at the ends of the needles in the cage at the corners). If you get a bearing, buy oem from the saw shop.

I replace them anyway. Every 20 hours in small bore dirt bikes in the day. I was too cheap to do top ends every 10 hours in 125's, but that would be ideal. I don't know why those wrist pin bearings don't come in the kits.
Awesome stuff, i’ll Use a hand lense I have, it’s only 10x but it should work!? I use to race my Cr 250, i’ll Get a pic :) the sound of those screaming two strokes is unbeatable right!!

1A4C4880-3D49-4133-8A79-BF5D0CC840CF.jpeg
 
holeycow

holeycow

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Oh, and you might want to make a "fork" out of wood to hold the rod steady. "Mad professor" posted a pic not too long ago..

And cover the crankcase with a clean rag while you are installing the circlips. Well, during the whole operation. You don't want anything to fall in there.
 
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