028 Super P/C Advice

[DanAyo]

Just got the saw running good, opened the muffler and now removed the cylinder. Both the cylinder and piston show no signs of damage what so ever. But the cold compression reads 130-133 after many pulls. The squeeze with gasket removed and both surfaces cleaned is .024.
Will replacing the rings and lightly sanding the cylinder bring back the compression?

Another option -
There is a Black Friday sale on a 46mm Hyway top end for $70.

I can go either way. I considered the top. That way I can test the waters on porting. Never done that before. Could get the top end and another set of rings for the OEM.

Looking for advice and ideas…

 

[Wood Doctor]

The Beatles: "Let it be, let it be, let it be, let be." Not sure why you removed the cylinder and piston.

 

[Binthewoods]

I would put back together with a new set of Caber rings.

 

[DanAyo]

WoodDoc, I think a lot of forum users would agree with you. It seems the Beatles might. But there is a certain group of people that like to tinker. They are inquisitive and always eager to learn. Good enough is never really good enough. I am proud to be associated with the later gang. My 028 has been with me for over 30 years. I have another chainsaw, so this one is my dedicated hobby. At 70yo I need all the hobbies I can find.

My family (AND WIFE) would definitely agree with you. But it’s in my DNA. I’m wired that way

Danny

 

[Chevboy0167]

I second just scuff the OEM cylinder and new rings. Remember to check ring end gap first. Also, pressure test the bottom end for crank seal leaks just because.....

Get a second saw for playin.

 

[DanAyo]

Thanks, all.
I ordered a set of Caber rings. It seems, (from the opinions on this forum) that nothing beats OEM. I hope the base gasket delete along with scuffing the cylinder and new rings will raise the compression. (Presently 130-133)

A few related question -

1. What is the proper way to scuff the cylinder
2. With the gasket removed and the surfaces cleaned the squish is .024. Is it possible to lap the bottom of the jug using wet sand paper and a smooth granite surface? I understand .020 is the desired squish clearance.
3. I recently opened up the muffler baffle and brazed a 5/8” pipe in place of the exhaust slots. I have never ported before. Can you suggest some basics for porting the OEM cylinder to get me started? I am mechanically inclined and like to learn. Maybe I should get a Degree Wheel and determine the port timing. Are 028 Supers very standard in this regard? Original squish was .037.

Thanks for any help,
Danny

 

[Maintenance supervisor]

Thanks, all.
I ordered a set of Caber rings. It seems, (from the opinions on this forum) that nothing beats OEM. I hope the base gasket delete along with scuffing the cylinder and new rings will raise the compression. (Presently 130-133)

A few related question -

1. What is the proper way to scuff the cylinder
2. With the gasket removed and the surfaces cleaned the squish is .024. Is it possible to lap the bottom of the jug using wet sand paper and a smooth granite surface? I understand .020 is the desired squish clearance.
3. I recently opened up the muffler baffle and brazed a 5/8” pipe in place of the exhaust slots. I have never ported before. Can you suggest some basics for porting the OEM cylinder to get me started? I am mechanically inclined and like to learn. Maybe I should get a Degree Wheel and determine the port timing. Are 028 Supers very standard in this regard? Original squish was .037.

Thanks for any help,
Danny

You can sand the bottom of a flat cylinder with glass or a granite surface and sand paper. A figure 8 or cross pattern of sanding is my preferred method.
As far as porting goes , I defer to the professionals . Some have posted pictures of their work and general numbers of what to look for . There's lots of snake oil salesmen out there though so don't believe everything you see, lol obviously.
Green scotch brite pads form the hardware store are my preferred method of resurfacing the cylinder. I'll split a wooden dowel with a hacksaw and slide a pad in it then chuck it up in a variable speed drill and soak it down with WD40 or whatevers is on hand.