Dolmar throwing chains

[Fatherwheels]

How is the clutch drum and bearing? try running it with the cover off and watch for wobble? something is going out of alignment...could even be a bent crank or bad crank bearing.

I just noticed this is the same poster who was putting a new seal on his Dolmar 421, he bought a new EA4300
too use as he worked on the Dolmar. Maybe the seal / bearing got overloaded and this is happening to the new
saw too, there could be an issue we are not aware of yet.

 

[Fatherwheels]

@redhawk23 , how old is your Dolmar, just noticed you are the same guy who was putting in a new
case seal into your Dolmar, have you it back up and running, was it throwing chains before you tore
it down. Seems strange two practically similar saws are doing this.

 

[peak98]

keep the chain tight...it is really as simple as that.

3/8lp is only rated for 3hp and the 421/4300 is 2.9 so there is quite a bit of stretch running those chains and with the tiny lp bars it doesnt take much and you throw the chain.

fordf150, please pm me a good number for you, I’m ready to order a bar and a couple loops. Sent ya a pm but don’t know if you received it or not. Thanks.
peak98

 

[Fatherwheels]

@fordf150 , @peak98 is looking for your number as above, and below
"
fordf150, please pm me a good number for you, I’m ready to order a bar and a couple loops. Sent ya a pm but don’t know if you received it or not. Thanks.
peak98
"

 

[redhawk23]

I used the saw today but didn’t pinch it at all. I tightened the chain to the point it stops rather quickly when the throttle is released. I think it’s too tight but we’ll see if it stops throwing chains.

 

[sean donato]

I used the saw today but didn’t pinch it at all. I tightened the chain to the point it stops rather quickly when the throttle is released. I think it’s too tight but we’ll see if it stops throwing chains.

I can run mine pretty floppy loose and not toss them, but generally pull them up just so they touch the bottom of the bar. Like just barely kisses the bar.

 

[redhawk23]

@redhawk23 , how old is your Dolmar, just noticed you are the same guy who was putting in a new
case seal into your Dolmar, have you it back up and running, was it throwing chains before you tore
it down. Seems strange two practically similar saws are doing this.

They’re identical saws. Maybe this saw requires the chain to be tightened more than any other saw I’ve used.

 

[redhawk23]

I can run mine pretty floppy loose and not toss them, but generally pull them up just so they touch the bottom of the bar. Like just barely kisses the bar.

You have a 421/4300?

 

[sean donato]

You have a 421/4300?

No, I'm speaking in general. A bar is a bar and a chain is a chain, unless something is wrong with one or the other.

 

[redhawk23]

No, I'm speaking in general. A bar is a bar and a chain is a chain, unless something is wrong with one or the other.

Yeah, I regularly use 3 other saws and rarely throw a chain.

 

[HarleyT]

Put up a pic of that sprocket!

 

[HarleyT]

Having to remove links is a clue.
Show us that sprocket.

 

[redhawk23]

Here’s a couple pics

 

[sean donato]

Doesn't look bad imo.

 

[Fatherwheels]

If those two bar studs are the same length, something is up, there is 1/8 of an inch
shoulder showing above the bar on the back bar stud, the front stud shows a smaller
shoulder above the bar, the bar should be point heavy and actually causing the opposite
to happen, lifting the tail of the bar up and reducing the visible shoulder, there also looks
to be dirt under the bar plate at the back, which again should cause less bar stud shoulder
to be visible, yet this is not the case.
Did you check the bars to see they are straight on both plains, not like propellers.
Have you turned the bar over during use.

 

[Fatherwheels]

My old Dolmar 421 threw chains and my brand new Makita 4300 is doing it as well so it has nothing to do with worn parts. It happens frequently and involves a minor pinch usually while limbing a downed tree. The chains are not loose, I’ve tightened more than I should and it still throws chains.

I had a chain or two shortened by a link but between using different saws I lost track of determining if that solved the problem, though I think it did and there’s really nothing left to try.

it seems like a design defect in the saw if I can’t use chains off the shelf.

thoughts?

OK reading this again, you removed a link from some chains to see if it helped, I never took a link off my chains
and they are 15 inch, and you say it happens when you get the bar pinched, that tells me the solution is to not get
your bar pinched, which stretches the chain when the engine snaps against it as it stops, that leads to a stretched chain,
which you have when you needed to remove a link, don't get the bar caught.
Catching the bar as often as you seem to do, you said it happens frequently, and then tightening too much to prevent
the chain coming off stretches the chain and grinds the clutch bearing and the shaft bearing out of the saw, that oil
seal you had to replace was no doubt related to over tightening too.
The picture I see is operator error, on a large scale, all the small things are being overlooked and are adding
up to what you would expect, trouble.
How did you get the bar slot behind the bar stud nearest the clutch full of dirt, the bar is clamped and nothing
should get in there, there is no pattern on that bar showing it was cleanly clamped like there should be.
When the bar plate is clean, the bar is clean and the side cover is clean, none of the above would be seen on your saw.

 

[HarleyT]

Was this a chain that was run on another saw?

 

[redhawk23]

OK reading this again, you removed a link from some chains to see if it helped, I never took a link off my chains
and they are 15 inch, and you say it happens when you get the bar pinched, that tells me the solution is to not get
your bar pinched, which stretches the chain when the engine snaps against it as it stops, that leads to a stretched chain,
which you have when you needed to remove a link, don't get the bar caught.
Catching the bar as often as you seem to do, you said it happens frequently, and then tightening too much to prevent
the chain coming off stretches the chain and grinds the clutch bearing and the shaft bearing out of the saw, that oil
seal you had to replace was no doubt related to over tightening too.
The picture I see is operator error on a large scale, all the small things are being overlooked and are adding
up to what you would expect, troubl

 

[Bubster]

One simple thing to check ,(and you probably have already),would be to check if the backing nut on the chain adjuster has came loose.If you have forward to backward slide on the adjuster,tighten the nut.

 

[cookies]

I see a worn out chain with rounded drive links and irregularly worn straps where they ride on the rail. I would suggest running a brand new chain and cleaning the bar groove really well... Clean and inspect the bar very closely with and without the chain installed.
it only takes grounding a chain once to get rocks or sand impacted in the groove under the chain that then will move around under the chain when the sawdust starts flowing.
I have the most difficult time throwing out chains...part of my brain prevents it with excuses of i'll use it to stump or it has another sharpening in it but the truth is the damn thing is two laps past its finish line

I just went through a similar problem, the saw felt like it was just struggling or working too hard in cuts..the chain was sharp and the saw was oiling but I could rock the chain too much in the rail side to side. It was allowing trash in and ended up pushing the tip apart allowing the roller tip to wobble and required tightening the chaintoo often. The bar went into the trash and a new one solved the issue.