MS 170 Tear-down

[roostersgt]

Glad to see you got the saw running. If you want you can install a carb from an 026 in there. You will need to mod a few parts as the carb is bigger but it allows for H and L adjustment. You will also need to drill a hole or two to allow a screwdriver in the to adjust it. I remember seeing this done here but I don't remember who did it. PM BSNELLING. It might have been him.

When you put the piston in, did you put some 2 stroke oil on the cylinder wall? This usually bumps up the compression a bit and protects the piston on itintial startup.

No, I used some TriFlo oil inside the cylinder. My dealer squirted fresh 2 stroke oil in the exhaust port to assist with the added compression. Like your suggestion regarding using 026 carb. That factory carb is definitely the weak link here.Any idea which make and model might work?

 

[K5krawler]

no, i used some triflo oil inside the cylinder. My dealer squirted fresh 2 stroke oil in the exhaust port to assist with the added compression. Like your suggestion regarding using 026 carb. That factory carb is definitely the weak link here.any idea which make and model might work?

wt-215

 

[Rookie1]

I was pokin around and found this thread. Maybe it will help. http://www.arboristsite.com/chainsaw/150605.htm

 

[belgian]

I'm digging this thread up again as I am repairing a MS170 for a good friend of mine. Thing had lost compression so I had to reorder new rings, bearings and seals for it.

Does anyone have a good trick on reinstalling that piston with the rings mounted. Darn clamshell design makes it real difficult to get the piston back without breaking the rings.....as you can imagine, already broke one....grrrr.

thanks

 

[sefh3]

I'm digging this thread up again as I am repairing a MS170 for a good friend of mine. Thing had lost compression so I had to reorder new rings, bearings and seals for it.

Does anyone have a good trick on reinstalling that piston with the rings mounted. Darn clamshell design makes it real difficult to get the piston back without breaking the rings.....as you can imagine, already broke one....grrrr.

thanks

Same design as the 1127 series but smaller. I take a carb adjusting screwdriver and grind an angle on it. Install the piston with rings on the crank. Mount the cylinder in a vise. Use the screwdriver and gently push the rings into the cylinder slow and steady. It takes some time but it works the best for me. I have heard people using a can and cutting it down to make a sleeve. I have never tried that though.

 

[Chris-PA]

On my Poulan clamshells, I've found it works well to use a small wooden stick inserted in the transfer runner to push the rings in towards the piston while pushing the piston into the cylinder. The rings are exposed from the sides there. However, those are dual transfers not quads, so they are wider.

 

[Fish]

The bottom of the cylinder has a slight bevel which allows working up with a small screwdriver pushing the rings in and working the piston up.

Not easily done with a bad hangover, butnot too hard for the patient.....

 

[belgian]

Same design as the 1127 series but smaller. I take a carb adjusting screwdriver and grind an angle on it. Install the piston with rings on the crank. Mount the cylinder in a vise. Use the screwdriver and gently push the rings into the cylinder slow and steady. It takes some time but it works the best for me. I have heard people using a can and cutting it down to make a sleeve. I have never tried that though.

The bottom of the cylinder has a slight bevel which allows working up with a small screwdriver pushing the rings in and working the piston up.

Not easily done with a bad hangover, butnot too hard for the patient.....

That's how I did it but still broke a ring (no hangover, Fish...). Visibility is quite bad on the lower ring when you insert the piston (with cylinder in vise). Keeping the rings centered around the pin is not easy working the piston down. I have a new set of rings coming, so will try again. thanks

 

[Fish]

I have heard a plastic zip tie works good, but have not tried it.

 

[belgian]

I have heard a plastic zip tie works good, but have not tried it.

Honestly, I think a zip tie is too thick to work well. I cut the ears of one my plastic ring clamping tools, but it appeared to thick as well. I may try the tin can idea though...

 

[old-cat]

I've only done one of those clam shell motors. I think the problem is the taper that squeezes the rings in is too rough. I think it would work better if you smooth out the taper with file or sand paper. If the edge of the ring is sharp, you can put a tiny bevel on it.

 

[Chris-PA]

Make sure you oil the tapered area, not just the bore.