Dolmar throwing chains

[redhawk23]

To answer a few questions:
1. what wear there is on the drive links is due to throwing it. The first chain I threw on the saw was when everything was brand new. I am confident wear on any part is not the cause (at least was not the cause).
2. I haven’t stretched the chains over tightening them because until yesterday I didn’t over tighten them because I know what proper tension is.
3. I flip the bar regularly
4. no screws are loose and nothing is bent
5. I’m confident cleanliness has nothing to do with it. If it does, this is one finicky saw. If it had dirt where there shouldn’t be any I’m confident I’ve cleaned the saw up before and still threw chains. For instance, I just sharpened the chain, flipped the bar and cleaned out dust and oil.

Since I don’t foresee never pinching the chain again I think I’ll get a new chain shortened and see if that solves the problem. (I’ll try to keep track of this chain somehow). I’m cleaning up a property after an F4 tornado so it should get plenty of use.

Hopefully, I’ll have something to report soon.

thanks for all the input

 

[Franny K]

The pictures provided in post 33 looks like close to new. No apparent damage from thrown chains on the plate between the bar and saw body or elsewhere. Like noted elsewhere no marking on the bar to indicate that it has been tightned well. These have a plastic clutch cover with inserts at the bar nuts that usually make a mark...... Would not most agree? Quarter inch pitch will be much worse. One can get into a rim drive and play .325 which will have somewhat larger drive links somewhat closer. Probabyl the .325NK would be the choice. How banged up is the clutch cover where it acts like a chain catcher? These things probably are not ideal to throw chains on a lot since there is no chain catcher and many folks are afraid of parts going nla, I have one spare new clutch cover.

I think the bar is against the powerhead in the picture, look at the adjuster it looks about right to me, the lowest threads of the rear stud are full of tree parts.

 

[HarleyT]

Show us a pic of the label on the bar.

 

[Fatherwheels]

I agree with the poster who said there is no signs of chain throwing on that saw in the picture,
which is good, for they can leave things quite scored up. I think the bar is pointing to the right
looking from the users perspective, because of dirt under the bar, that would result in a fair
angle difference between the drive sprocket and the bar, I would not want to see that on any saw
running near me, a whole bunch of small things catch my eye and they do add up to unwanted trouble.

 

[redhawk23]

As I said, the saw is not normally this dirty and on this day I didn’t throw a chain. I don’t think throwing chains is correlated with the times I’ve maybe flipped the bar and not cleaned it well.
I would be pleasantly surprised if dirt had anything to do with it. And if dirt has anything to do with it, it’s specific to this saw because I don’t treat the other saws I use differently and I rarely throw chains.

I

 

[J D]

You seam pretty confident the saws are as they should be & that (at least initially) chain & bar wear were not the cause either... That just leaves operator & environment (ie, these are the saws you use for limbing).
Are you sure you haven't developed a habit of twisting or flicking the saw/bar as you limb? I've seen people do this subconsciously & it would make sense that you would use those 2 very similar saws the same way but not necessarily others.
It won't help that each time you throw the chain it gets easier to do it again.

 

[Philbert]

Even on properly tensioned chains it is possible to ‘throw’ a chain. The loops are spinning at 50 - 60 MPH, and centrifugal force pulls the chain away from the bar. We have also all seen the images of each cutter rocking backwards when biting into the wood (sometimes referred to as ‘porpoising’).

Not so much an issue when cutting large pieces of wood, but when limbing in brushy conditions, a small twig can get underneath a tie strap, and lift it off of the bar just like a tire lever.

Clear way small brush, and avoid sharp or sudden twists of your wrists, to reduce the risk.

Philbert

 

[Fatherwheels]

Chains, especially smaller gauge ones can stretch a lot from you put them on,
they are not a fit and forget item, they need constant monitoring and tightening,
they also need loosening as when they cool down they will shrink and pull tightly
against the bearing in the saw, that destroys the bearing, it can flat spot it and causing
it to slide instead of roll, that wont go on for long until you are in trouble.

Also, use a good brand of chain, I think Stihl make a chain that will fit that saw, so do Husqvarna.
I turn my bar over every three tanks, I carry a tooth brush small enough to slide in above the chain
and pull / push the sawdust and dirt out, then I work from the bottom and back to clean the area all out,
then I loosen the nuts, remove the cover and clean it before removing the bar and cleaning it / the mating surfaces,
again the tooth brush does all this with a couple of swipes, then a few pulls down the bar rails from nose to tail with
a small piece of wire I bend onto the tooth brush by drilling a hole in the brush, this takes all takes a minute or so to do.

Bars need turned, and chains need rotated in use too, the second time / after six tanks I will use a new different chain,
on that bar, I will not use the chain off my identical saw, I keep them apart so I know when something goes wrong its
related to a particular saw, setup, unless I damage a chain and have no choice.
As mentioned already, cutting style can be a cause of throwing chains especially in certain cutting environments,
small twigs will get in and send your chin off, this too puts incredible strain on your saws bearings.
A bigger saw with longer bar can soak up some of the stress but a smaller one will stretch the chain and pull badly
against the bearings in the process.

With the info posted in this thread, you will be better able to spot the danger signs in regard to derailing
chains, when it all comes together the light will come on, you will see things you did not before,
like riding a bicycle, its hard to forget.

 

[tomalophicon]

I had a Makita EA3201s that kept throwing chains from new - no matter what I did it threw the chain almost every time I used it.
I went to the dealer who showed me that the company had redesigned the drum to have a rim above the sprocket that stops the chain coming off. A have snipped a pic of the IPL below. Maybe you source a similar sprocket from the dealer.
Your sprocket looks like the older one I had.
Never had a problem after installing the new drum.

Tom.

 

[Fatherwheels]

I had a Makita EA3201s that kept throwing chains from new - no matter what I did it threw the chain almost every time I used it.
I went to the dealer who showed me that the company had redesigned the drum to have a rim above the sprocket that stops the chain coming off. A have snipped a pic of the IPL below. Maybe you source a similar sprocket from the dealer.
Your sprocket looks like the older one I had.
Never had a problem after installing the new drum.
View attachment 926823
Tom.

What gauge chain did the Makita EA3201 have.

 

[tomalophicon]

What gauge chain did the Makita EA3201 have.

3/8 lp

 

[Fatherwheels]

To the OP, did you tune the saw, do you have a video of it running.
What am wondering here is, I can tune mine to send the bar
oil flying off the chain with way too much fuel on the low jet,
this could also impact chain stability especially if cutting branches
or twigs just too big for a hedge trimmer, the sudden take off of the
engine coupled with a light chain could be helping the chain ride up on the sprocket, just don't know if this is a possibility.

 

[Fatherwheels]

3/8 lp

@tomalophicon does the EA3201 have a rim drive or just a regular sprocket.
I use .325 narrow kerf on both my EA4300 saws with the regular sprocket, no chain trouble, and I have not heard of others having trouble with the 3/8 lp, puzzling to have two saws the same doing it like in the Op 's situation.
@redhawk23 check your bar to see if it is a 3/8 pitch, and not .325.

 

[tomalophicon]

@tomalophicon does the EA3201 have a rim drive or just a regular sprocket.
I use .325 narrow kerf on both my EA4300 saws with the regular sprocket, no chain trouble, and I have not heard of others having trouble with the 3/8 lp, puzzling to have two saws the same doing it like in the Op 's situation.

It's a rim sprocket on the drum as pictured above.
The issues could definitely be unrelated but the manufacturer must have redesigned the sprocket for a reason
Tom.

 

[Fatherwheels]

It's a rim sprocket on the drum as pictured above.
The issues could definitely be unrelated but the manufacturer must have redesigned the sprocket for a reason
Tom.

How is the redesigned one different.

 

[Franny K]

It's a rim sprocket on the drum as pictured above.

This is a spur sprocket, there is no rim to speak of.

 

[Fatherwheels]

View attachment 926879
This is a spur sprocket, there is no rim to speak of.

I taut I taw dat too, no rim in sight, taut I was loosing it.

 

[HarleyT]

I taut I taw dat too, no rim in sight, taut I was loosing it.

You guys beat me to it!!


I am not familiar with Makita Dolmars.
Could he have a bar for the full 3/8 on his 3/8 l.p. saw? That is why I wanted to see the label on his bar.

The sprocket he has looks bad, but not bad enough to give him the trouble he is having.

 

[redhawk23]

3/8, it’s the original bar and chain the saw came with

 

[redhawk23]

I had a Makita EA3201s that kept throwing chains from new - no matter what I did it threw the chain almost every time I used it.
I went to the dealer who showed me that the company had redesigned the drum to have a rim above the sprocket that stops the chain coming off. A have snipped a pic of the IPL below. Maybe you source a similar sprocket from the dealer.
Your sprocket looks like the older one I had.
Never had a problem after installing the new drum.
View attachment 926823
Tom.

That’s interesting. I wonder why they made that change. If it was due to chains coming off I wonder what was causing it.