Stihl 038 AVS Farm Boss (late ‘80s) worth saving?

[spudulike]

Just now, Ratman said:

 

Be a peach if it is a genuine cylinder that will clean up! What makes you think it is Spud? I can make out the ‘A’ etched on the top but didnt really associate it to anything, and the plug looks like an ebay special. Were the 038 cylinders finished differently? As in they were a plated bore as opposed to a nikasil coated, sure i’ve read it somewhere

 

The markings on that flat plate are EXACTLY the same as Stihl use on their pistons and some of their cylinders. Aftermarket cylinders very rarely mark their cylinders A or B.

The plating may be chrome, more liable to chip but still strong. 80s bikes were Chrome bores hence this view.

[spudulike]

The "A" means it is slightly smaller in bore size, "B" means slightly bigger and was from the days cylinders and pistons were matched.

[Ratman]

The markings on that flat plate are EXACTLY the same as Stihl use on their pistons and some of their cylinders. Aftermarket cylinders very rarely mark their cylinders A or B.
The plating may be chrome, more liable to chip but still strong. 80s bikes were Chrome bores hence this view.

Yeah with ya! Mate had a yam tzr with plated bores, piston broke up and destroyed the bore, hence the coming to know about the bores being plated, cost to do up saw the rest of the bike stripped for bits.

[Ratman]

The "A" means it is slightly smaller in bore size, "B" means slightly bigger and was from the days cylinders and pistons were matched.

You are a font of knowledge sir! Every day is a school day! 🤠[emoji106]

[Just_Alex]

3 minutes ago, spudulike said:

I am sure we can give it a go.

Legendary status...I just do my thing, I am not on Facebook so probably miss most of it but just sort out issues and get saws working as they should or better....people are happy...all good!

Just take the compliment @spudulike 😄

 

what tools would I need? I downloaded a manual for the 038 but that’s as far as I got, I don’t think it’s even the service manual yet. Sat through a video on YouTube of someone taking apart a magnum to get at the crank and it looked like an ordeal, with some kind of specialised c-clamps thing that seemed to exert force to pry apart the casing… how far do I need to got to not mess it up beyond repair?
 

Thank you and everyone for your kind welcome and helpful responses, I feel chuffed to bits that there’s hope for this old machine (good thing is I am not in a rush on this one as I will make alternative arrangements just soon can get going actually “milling” something. 😊)

038_Manual.pdf

[Just_Alex]

This is the thing I mentioned. Some kind of bearing press? Would I need one to get the case apart to change the seals?

[adw]

Looks typical Mahle cylinder, Husqvarna cylinders and pistons were graded a b c and even d, it all depended on the final hone of the cylinder, I guess today the manufacturing is so much more accurate, 

[adw]

4 minutes ago, Just_Alex said:

This is the thing I mentioned. Some kind of bearing press? Would I need one to get the case apart to change the seals?

As you are only doing one it’s not worth shelling out on the tool, nice to have though, small blow torch, heat up to expand the alloy crankcase and TAP with copper or hide mallet, you could borrow the tool if you do not fancy heating it up.

[Ratman]

This is the thing I mentioned. Some kind of bearing press? Would I need one to get the case apart to change the seals?

I’ve never used one, i just tend to pry in places that dont cause harm and use the aid of a vice along with a small copper hammer, but i’m just rough! 🤠 (sure Spud’s gona go all fury on me and call me a wanker for doing so [emoji16]) but i just take my time and use a bit of patience. You can buy the chinese splitting tool for peanuts but never seen one in action or felt one so can’t comment. Just do what you feel comfortable with, and if your unsure then do what your doing now and just ask away, someone will have an idea or answer for ya.

[spudulike]

I would really avoid splitting the cases. It is worth checking there is no play in the crankshaft but if there is, throw the towel in.

For simplicity, take the impulse line and carb boot off and check them out carefully. TO fully check them, you need to seal off all the crank openings and check with vacuum and pressure with a Mityvac or similar but they are £60-80 hence my comment. 

look for damage or splits/holes and replace if found to be faulty. 

Start with this and as far as the cylinder goes, use acid or strong alkali to shift it....battery acid, brick cleaner or caustic soda/strong oven cleaner can work well! Apply, let is stop fizzing, rub with wet and dry and start again.