Dolmar PS-7900 Air Filter Question...

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The particle size that is getting through my filter certainly wouldn't be big enough to cause visible scoring in the bore. Mine hasn't got the pre filter though its a September 06 model.

you have to be kidding.... Even the finest GRIT will take out aluminum...
 
you have to be kidding.... Even the finest GRIT will take out aluminum...
Cylinder walls are plated and the rings are steel. Seems like it ought to with stand some dust. Just look at the old SuperXL's. The filters just kept out the big pieces. Plenty of dirt and dust got by those poor excuses for filters and those saws still run after many years.
 
i've never gotten ANY particles (that i know of)thru the filter of my makita dcs 6401, but the saw has maybe three hours total use on it . . . makes me want to go double check that filter ASAP
 
Cylinder walls are plated and the rings are steel. Seems like it ought to with stand some dust. Just look at the old SuperXL's. The filters just kept out the big pieces. Plenty of dirt and dust got by those poor excuses for filters and those saws still run after many years.




I agree... wood dust seems to have little effect, but harder stuff does.

It's the piston skirt that wears - aluminum.... and eventually the nikersil/chrone will be gone -check out some concrete cut-off saw P&C...

Oh.... around here when Mt St. Helens popped off... saws lasted a day or two, to maybe a week... any brand.
 
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you have to be kidding.... Even the finest GRIT will take out aluminum...

I'm not an idiot but there is a difference between "wearing out" and visible scoring. The dust inside the filter looks like wood dust (but its fair to assume there would be a "dirt" component) and mixed with the oil residue is actually more like a "non gritty" paste. I suppose though it could form lumps out of sight in the intake tract and drop something bigger in that could cause some sort of noticable damage.
I've probably cut for around 12 hours with the 7900 since new. 90% of the wood has been dead, dry, relatively clean wood compared to some I've cut in the past with other saws, but even then you'll always get some wood dust form or some dirt dust from the bark (I am in Australia after all in an area with less than 10" average annual rainfall - there is always some dust around :) ), no matter how sharp your chain is. I've got more than enough new or dealer sharpened chains to not have to use blunt ones.
Good link above too re: Stihl MS361. Thanks.
 
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Well, compairing the filter to the huskys the dolmar plain sucks PERIOD. For a saw of that size the filter is way too small. I have sawed some timber that was fire burnt and rotton with my 372 and the in side of the filter is spotless, I ran the saw for more than 90 hrs in these cutting conditions (a month worth of sawing)
Also the stihls I've owned never got dirt past the filter as long as I greased the rubber seal on the filter (044, 046, 066, 084).
The dolmars are all awsome saws but the filter just needs a lot of help in redesigning it:givebeer:
 
The dolmars are all awsome saws but the filter just needs a lot of help in redesigning it:givebeer:

I absolutely love my 7900, but my first thought after seeing the air filter was "hmmmm, this isn't good." I hope any redesign on new models is backwards compatible because I'm not impressed with the current design... Other than than, awesome saw.
 
Do you guys get supplied with both filters?
I got a fleece one and a mesh one with mine and i havnt noticed any crap past the fleece one yet but i havent cut anything dirty with it yet.
 
Mine came with a fleece filter standard. If they do release any new filter system I hope it fits the older saws - I'll buy one in a flash.
 
My 7900 came with the nylon mesh stock filter. I bought the vlies.
I was complaining about this a few mos ago.


I tell you the saws are designed fairly well but any chains only as strong as its weakest link.. and the stock filtration on 7900's is a joke.
 
Just checked mine, and sure enough, there's enough crap inside the fleece filter to be a concern.......all trapped by the reversion oil. Looks like Aussie Ironbark and White Box is pretty clever at beating German Fleece.

I slotted in the spare filter and greased around the lip (that should be a soft seal Makita/Dolmar....) so we'll see what happens.

Cleaned out the old filter (first time I've washed it, just tapped out previously ) and it helps to read the manual to discover that the filter splits in half for easy cleaning :monkey:

FWIW, air filters become more efficient as they load (ie. they trap a greater amount of finer contaminants) up until the point that they impact performance.

and to all those blokes that stated they make chips not dust... :rolleyes:
 
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Odd

Dull chains throwing a lot of fine dust can cause this. So can cutting very very hard wood, i.e. locust/hickory etc... I'm the first one to admit I'm not a huge fan of the filters on the dolmars. On same hand, I've got a 510, 5100, and 7900 I cut probably 100 cord with last year and haven't had a single problem like everyone has said yet. My 7900 has been cutting for 2 yrs now w/out a hitch. I've seen a small amount of dust on the inside, nothing to complain about I don't think compared to the old screens that are on ALL the older saws. Yet for some strange reason they just chugged along w/out a hitch. I even drilled holes in the top of my 5100 for more air flow, VERY small holes and probably about 20 of them, and don't seem to have a huge problem with the dust inside the filter. I'd say try a pair of nylons with a rubber band. Around the base I've always used a small amount of silicone where the filter meets the Carb housing. I've done that on every saw I've ever run anyways, and I clean the silicone off and use new every few months...

:popcorn: :cheers: eh?

I blow out my filters about 2x's a week depending on how much I cut, which as of late is about 3 to 4 days a week for 6 or 7 hrs...
 
My 361 lets in just as much fine dust as my 7900 or 5100. I really think as long as the partials are small and soft (wood not sand), it's a non issue.

http://www.arboristsite.com/showthread.php?t=75377&page=7


We don't have a 7900, but I agree on the 5100 and 361 - I consider it a non-issue until proven wrong!

Btw, the Dolmar has US type filter ("flocked"?), while the Stihl has a mesh one.

All my Huskys have mesh, but still stay cleaner on the inside of the filter, as well as on the outside.
 
Which is the case here. From the numbers I've seen, our hardwoods, (and it's pretty much all we have) and their densities make your hardwoods look soft. ;)

http://www.arboristsite.com/showthread.php?t=73645

Indeed :)

I've been using nothing but Oregon LGX in my 7900 in 20" and 32" bars and that rips into dead aussie hardwood pretty well. Seems to hold its sharpness for quite a while too. The 32" bar makes the old Dolmar work pretty hard though when buried in dead red Gum. I've also got some new full chisel Windsor chain too but will try to save that for a special occasion. Not sure what that will be though...
 
I have to say I have had No trouble with the filter on my 7900 too the point I think I wasted money on a spare lol. I read this post last night Just got back from cutting some very dry pine mind you only ran two tanks through it but it is spotless. The out side of the saw is very dusty yes very sharp chain was making big chips but you still get lots of dust. The air box is even clean, dare I say Jred/Husky Clean.
I also did my good deed for the day by helping out another firewood cutter. Cutting on public land in the forestry on a Well Head road had another cutter pull up and say ah you got the good spot I told him tons of trees and the Dog would like some company as he had his Lab with him. He had a brand new MS 290 on it's Maiden Run. He forgot his Scrench and having a brand new truck no tools with him to adjust the new chain.So I lent him one of mine, after we cut are loads of wood he saw me pop of my top cover and have a look he asked what I was doing I told him so we had a Look at the Stihl and guess what No dust got by the filter either. Then I told him about AS, so next time we cross paths he will probably have a new MS460:clap:
P.S I told him don't get a fat ass 441 I also steered him to the Jred dealer too.:)
 
I have to say I have had No trouble with the filter on my 7900 too the point I think I wasted money on a spare lol. I read this post last night Just got back from cutting some very dry pine mind you only ran two tanks through it but it is spotless. The out side of the saw is very dusty yes very sharp chain was making big chips but you still get lots of dust. The air box is even clean, dare I say Jred/Husky Clean.
I also did my good deed for the day by helping out another firewood cutter. Cutting on public land in the forestry on a Well Head road had another cutter pull up and say ah you got the good spot I told him tons of trees and the Dog would like some company as he had his Lab with him. He had a brand new MS 290 on it's Maiden Run. He forgot his Scrench and having a brand new truck no tools with him to adjust the new chain.So I lent him one of mine, after we cut are loads of wood he saw me pop of my top cover and have a look he asked what I was doing I told him so we had a Look at the Stihl and guess what No dust got by the filter either. Then I told him about AS, so next time we cross paths he will probably have a new MS460:clap:
P.S I told him don't get a fat ass 441 I also steered him to the Jred dealer too.:)

Did you scare him with the Troll from Norway?

:biggrinbounce2: :laugh: :laugh:
 

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