395xp, piston stop or air ratchet?

[B_Turner]

On my 395 to change the sprocket or lube the rollerbearings it has a nut on the outboard clutch.

What is the "preferred" method for removing it?

Plastic piston stop?

Air impact wrench set to very low power running on a regulator set very low?
And very very gently bumping the nut until it lets loose (without the piston stop of course)?

I won't say which way I have been using to avoid ridicule.

Just wondering. Bill

I did a bit of searching and didn't find a thread on this, but sorry if I missed it.

 

[rahtreelimbs]

As far as the clutch bearing lube goes most Husky's that I have seen have a hole in the end of the crankshaft that allows you to grease the bearing.


For clutch removal I just use an impact gun and let the saws compression apply the necessary opposing force needed. I am not a big fan of piston stops!

 

[aquan8tor]

stihl's plastic piston stop has no chance of damaging the piston, unless you wedge something else in there too. HDPE is pretty soft compared to nikelsil or chrome coated steel or aluminum alloy. I wish I had an impact wrench, and I'd use it if I had one, but $3.95 is a cheap, safe alternative until I've got a bigger workshop.

 

[Chopwood]

I ahve taken the clutch off all of my saws many times with an impact gun. This includes my race 3120 huskys, valued at about three grand a piece (three of them). The only time I used a piston stop, I could not bring myself to reef on the clutch that hard. It felt like I would break the rod or piston if I put enough torque on it. My $.02.

 

[Four Paws]

Lots of us use a piece of nylon rope, stuffed into the spark plug hole as a piston stop.

 

[Justsaws]

Air wrench against compression. No problems. Piston stops a few problems. Rope, only did it a couple of times. Air wrench seems to be the best on the big saws as long as they got compression.

Feather the trigger so as not to spin the clutch out of it's springs.

 

[046]

I've used the rope method with a hand wrench with no problems.

seems enough folks have done both piston stop and impact method without damage.

 

[manual]

Just don't let the rope slip into one of the ports.

 

[Lakeside53]

rope... and no air... Then you can't damage it. Sure air works, and I use it more often that I should, but...

 

[GPH85]

I use the claw hammer method Seriously, and have never had any problems with anything breaking. Tried the rope, but never could get enough in to do any good.

By claw hammer I'm referring to using the claws on the back of the hammer to put into flywheel cooling fins, then the hammer will either catch on the work table or handle on the saw. No problem removing any nuts or bolts on the crank with this method...

 

[Lakeside53]

I have a good collection of flywheels missing fins from guys using methods like that..

 

[GPH85]

Sorry for even mentioning it then... I've done this hundreds of times and never once had a fin break or even crack, but I guess there are always the saws out there that use a thinner cheaper fin setup that will break easier. The saws I do this to are Homelites and Husky's. Never tried it on a Stihl. Don't know how it would work out on them? I have seen fins break from people using screw drivers to stick through the fins. Screw drivers don't wrap around the fins like the claws on the hammer and creates a twisting motion on the fins, so I could understand something like that breaking them.

If completely eliminating this method, then I would use the air ratchet method, but watch the hammering of the ratchet closely due to the internal effects it has on the engine. It's just like having preignition to the bearings and everything, but a lot of saws out there today are built too cheaply to use the dead stop. Seen some pretty bad looking pistons from that one.

 

[Lakeside53]

I can see how the right shaped claw hammer may well work.. I just stay away from jambing the flywheel with anything.

Later saws may also have the keys cast as part of the flywheel - they spin off easily with air use... another reason to be careful with air impact wrenches.

 

[cbfarmall]

Tried the rope, but never could get enough in to do any good.

If you haven't already, you'll probably need to knot the rope. I've got a length about 1" between knots. When I used it on my 090, I had to put the knots in knots I guess because the combustion chamber was so big. What a pain that was.

Anyhoo, I use rope or an impact but certainly not at the same time. Somebody once tried to tell me there was no problem with sticking a screwdriver in the exhaust port to lock the piston. I still haven't figured out if he was joking.:bang:

Chris B.

 

[oldsaw]

I'm a rope guy.

Mark

 

[PES+]

You will ruin alot of starters that way

If you do not use a stop or rope and pull out the starter rope BEFORE you lock the piston you will hammer all the recoil parts to a premature death. I have replaced scores of Husky and Jonsered pulleys and lots of springs and pawls on lots of Stihls due to others not taking this step.
But I have had some customers insist that it is a waste of time so.....
The customer is always right

 

[jomoco]

I sure hope no amateurs read this thread

While I understand what you guys are all talking about, what about the true amateur or home owner that reads this thread, decides to try and take the clutch off his saw using any of the many techniques described, not realising that all clutch threads are reversed, and busts his saw.

Just remember these threads are read by many different folks, and not all of them have alot or any real experience in these matters that most of us take for granted,

jomoco

 

[PES+]

Good point

I failed to mention the destruction occurs putting the clutch hack ON due to the left hand thread.
I'm tired

 

[GPH85]

I guess when you summerize everything up here. There is NO one great method to use...

If you use the jamming flywheel method, you run the risk of busting flywheel fins. I'm assuming if you use some sort of screwdriver jamming method. Have seen some bust with that, but never any using the claw hammer and gentle turning of the wrenches "no beating on with a hammer"...

If you use the obvious jamming through the exhaust port, you distort the cylinder and depending on your machining capabilities of grinding the hump in the cylinder back down, you may wind up replacing both cylinder and piston using this method...

If you use the air wrench or air hammer method, you run the risk of tearing up starter pawls and other starter parts not to mention the rare chance of stripping threads on cranks, busting washers or even ruining internal engine parts from the quick back and forth slapping that takes place inside an engine when using air hammers...

If you use the jamming piston with rope method, you run the risk of busting your piston "depending on how cheaply made it is and just how well the rope is spread out in the combustion chamber" and worse maybe even bending a connecting rod "I say worse because you wouldn't really know it until you went to running your saw and realized the timing was all wrong and it has no power = could ruin something else"...

SO now you have to ask yourself, of these negatives which would be easier, less time consuming and less exspensive to fix? I choose the jamming flywheel with claws of hammer method. You can either have someone weld the fin back on and grind it back down to original shaping or buy a new flywheel, which most of the time can be found on ebay, or possibly a scrap heap of saws of which you have at your house or one you may know of in general... Yes I'm sure a new flywheel with todays price's would be about the same as the price of a piston, but I'de still rather replace a flywheel over an internal engine component... PLUS, I've never had a flywheel fin break or even crack from using the claws of the hammer, but that's not to say it wouldn't happen on one model of saw compared to another...

Don't know, what's your thoughts?
Greg

 

[B_Turner]

If you do not use a stop or rope and pull out the starter rope BEFORE you lock the piston you will hammer all the recoil parts to a premature death.:

I am not sure I follow the wording here. Are you saying that if you do use a stop of some kind you must pull out the starter rope first?

Not trying to be a wise guy, just trying to make sure I get exactly what you are laying down. My confusion is the word "not" which I bolded in the quote.