Dull chains...does it really kill saws....how?

[T.Roller]

Is it possible that some saws die because they are ran dull causing bar/chain friction, and impact/vibration, as the dull tooth hits wood, that destroys the pto bearing. Then a leaky seal causes burn down, either from the loose bearing, or the seal fries and the bearing goes loose. The order doesn't really seem that important. The result is the same. AND

Is it possible that some saws die because they are ran dull until the fines build up in the filter until it goes lean on oil. As fuel/air is reduced by clogged filters until the amount of oil per rpm if you will shall be reduced whether your at 50/1 40/1 or 30/1. The engine will run hotter with less fuel going in the cylinder weather the mixture is correct at the carb or not. These are air cooled and perhaps more accurately, fuel cooled engines. Then lesser volume of oil has to work harder at a higher temp. Perhaps then you would see a fried exhaust side piston.

Less air, and less fuel, and less oil, even if it sounds rich as the air fuel ratio is now a lower ratio with less air velocity. Sure when the mixture hits the cylinder theirs more fuel than air, but how much total charge is getting in with less velocity at the transfers. This would be worse on a compensating machine, not better, ie compensating carb's and at/mt. As you have less over all flow per combustion event and less power and much less cooling.

And why not both sometimes. Sometimes stupid brakes in more than one way. It is more likely than not, not a single path to destruction. But several converging paths of poor decision. 50/1, clogged filters, ham handedness, dull chains. Just plain stupid

What can be agreed is running a dull chain is stupid, your likely to burn your piston, and maybe a cylinder. You can guess about the link, or you can tell the short truth. Running dull chain is bad mm kay. So is riding a bike on a flat tire. Maintenance is its own reward. Like they say. If you got 6 hours to axe down a tree spend 4 sharpening the axe.

This is all my opinion. Please tell me how i'm wrong. I'm just trying to learn like everybody else. As my final thought, doesn't rpm tend to kill the flywheel bearing first, not the pto. I'd be inclined to believe that heat soak, impact of dull teeth on wood, and higher rpm, work together to toast the pto bearing. Not just one lone terrorist, but a cell if you will.

Agreed

 

[Lone Wolf]

A dull chain in, and of itself doesn't necessarily "load" a saw more, but the dumb$hit dawging the saw in, and levering up on the handle certainly does "load" said saw.

Yup!

 

[Philbert]

Is it possible that some saws die because they are ran dull . . . This is all my opinion. Please tell me how i'm wrong.

This is your best post yet!

(Welcome to the site).

Philbert

 

[jmssaws]

I get to see lots of people's saws and have seen some things that you couldn't believe on saws that still run.

There incredibly tough but regardless of what kind if it's used enough it will eventually break,no way around it but you can postpone it by having common sense and respect for yours and your employer's equipment.

 

[rogue60]

I don't think anyone is saying a dull chain is a good thing we all know that its not.
For any of these failures to happen bearing/piston melt down in a saw with no air leaks (seals still good) something needs to happen 1st and that's oil film breakdown is it not? would the same saws still have sezed did bearings in running some of that synthetic racing bike oil designed for extremes many run here? I doubt myself. Just my 2c

 

[jmssaws]

This 084 was 100% killed by a dull chain
Poor old girl had it ruff but she's all better and ported and going to a good home with sharp chains.

 

[Iron.and.bark]

I kinda agree on that one people seem to accept melted piston smeared up and down the bore is normal if a saw is pushed hard and nothing to do with the lack of oil in the mix. I've pushed 066's to the point of on fire in 40+ celsius heat with no let up for hr's a day in summer and the pistons and bore are fine doing that for years, but that's not running what Stihl recommend for the oil mix.
You see it a lot in the biggers saws like the 880's only had a few tanks through them and already showing transfer on the exhaust side running 50:1 as the Stihl shop said that's the best mix to run lol.

Yep, completely agree about the ratio. All my saws live with 25:1.

My 3120 milled well over 1000 slabs, piston and bore had essentially no transfer at all after this use. Piston and cylinder was perfect until crank eventually died and spat some big end bearing parts up through the transfers.

On a humorous side note. No idea if this story is true, but was told by an old dealer.

He went out cutting a load of firewood for the local lions club (charity organization) with another bloke. He went to one log, and the other guy headed over to another log abit further away.

Starts up cutting, looks up between cuts and see's this smoke billow up from where the other guy was. Turns out guy was using an 090 with the chain on backward, got a fair few inches in and set the log on fire.

True or not I like the story.

 

[Al Smith]

There's three things you will do at least once.Cut dirt,put a chain on back asswards and put oil in the gas tank.

 

[Mattyo]

This 084 was 100% killed by a dull chain
Poor old girl had it ruff but she's all better and ported and going to a good home with sharp chains.View attachment 51783 View attachment 51784

Did the pto side seal get killed by the heat and then the saw sucked air?



btw, i like the idea of running a corded electric saw sharp, then dulling it against some dirt, and running it again and measuring the load.

 

[jmssaws]

Did the pto side seal get killed by the heat and then the saw sucked air?



btw, i like the idea of running a corded electric saw sharp, then dulling it against some dirt, and running it again and measuring the load.

Nope just heat got it.
The clutch and drum is blue like I've never seen.
Not a single problem with the saw just burnt up

 

[jmssaws]

Make some cuts with a sharp chain then stick it in the ground and make the same cut again with the same amount of pressure as the sharp chain and see which loads the saw most.

You don't have to pry on a dull chain to kill the saw,leave it tuned the same and let it self feed with a dull chain and see how long it lives.
Especially a strong saw

Probably kill it faster not applying pressure than prying on it.

 

[MustangMike]

put oil in the gas tank

Never done that ... but I have put Fuel in the oil tank!

 

[jmssaws]

There's three things you will do at least once.Cut dirt,put a chain on back asswards and put oil in the gas tank.

I turned my sugi over the other day for the first time in a year and ran it some,pulled the bar and chain and put it in a different saw and made it to the mule to go cut before I noticed that the chain was backwards.
I put my bar on right side up.

 

[Philbert]

Anyone who says that they never put a chain on backwards at least once . . . hasn't mounted many chains.

Philbert

 

[Dub11]

Anyone who says that they never put a chain on backwards at least once . . . hasn't mounted many chains.

Philbert

What about inside out ???????????

 

[Al Smith]

Once upon a time a long time ago an online poster who went by the handle of "romeo" had a bike engine saw with opposite rotation and a left side mounted bar .He had to put the chain on backwards . I think he said he was in New Mexico,funny to read about .I have no idea where he drifted off to .

 

[danimal]

Anyone who says that they never put a chain on backwards at least once . . . hasn't mounted many chains.

Philbert

yep.

 

[Dub11]

Anyone who says that they never put a chain on backwards at least once . . . hasn't mounted many chains.

Philbert

Or just sharpen both side of the tooth???

 

[CR888]

="Al Smith, post: 291755, member: 537abo7e upon a time a long time ago an online poster who went by the handle of "romeo" had a bike engine saw with opposite rotation and a left side mounted bar .He had to put the chain on backwards . I think he said he was in New Mexico,funny to read about .I have no idea where he drifted off to .

I remember Romeo....he knew a thing or two about fast saws, chains, pipes & badass bikesaws.

 

[ABarrick]

Holding one wfo tuning it makes my hair stand up.
I don't do it but just a second.
I see guys hold one wfo forever,no load rpm is bad for things.

I wish I could double like that post. My local Stihl dealer thinks saws can just rev wfo forever. He'll fuel a new saw, and as soon as the thing fires it's wfo for about 10 seconds... Makes me cringe. I take mine home in the box now.