dolmar PS-421 mods

[fordf150]

Could you please tell me the Model number on that bar? i don't see a 16" .325 Oregon bar that has the oiler holes that fit the Dolmar 421.
Thanks in advance.

here is the instructions for modifying K095 laminate bars to fit but if you want direct fit with no mods your looking for K041 mount bars

This saw didn't get it but I took a couple pictures just to show what is needed for installing a .325 bar and chain on these saws. A clutch drum and bar from a 5105 plus a 10x16x.2 mm shim is needed. This is probably a worthwhile modification just to have rim sprockets instead of spur. The bar needs slight modification to allow it to oil. We drill 2 holes in the groove down through into the adjuster holes. Black lines show where to drill. That is how I run mine and have set a few up to run it. Haven't ran anything but a 16" .325 on these but sticking with 3/8LP an 18" bar is pretty common. View attachment 358476 View attachment 358477 View attachment 358478

 

[Chris-PA]

If you need to modify a bar hole a bit a chainsaw file will remove material faster than you might think.

 

[CoreyB]

If you need to modify a bar hole a bit a chainsaw file will remove material faster than you might think.

I don't think a file will work for that mod.

 

[Chris-PA]

I don't think a file will work for that mod.

I've done similar mod in this way:


Basically the goal was to open the adjuster hole to the bar groove.

 

[CoreyB]

I've done similar mod in this way:
View attachment 508538

Basically the goal was to open the adjuster hole to the bar groove.

Ahhhh. Cool

 

[MountainHigh]

thanks guys .... I've got a couple of K095 bars for my 346 - might hack one to fit.

Any suggestions for 16" K041 bar?

Looks like this is the one to get - not sure about the low kick back chain?:
part number 105711
Chain: 20BPX saw chain ; .325" pitch; .050" gauge; 66 drive link
Bar: 160GLGK041 Pro Lite® ; K041 mount

http://www.oregonproducts.com/pro/products/combos/combo_105711.htm

 

[fordf150]

thanks guys .... I've got a couple of K095 bars for my 346 - might hack one to fit.

Any suggestions for 16" K041 bar?

Looks like this is the one to get - not sure about the low kick back chain?:
part number 105711
Chain: 20BPX saw chain ; .325" pitch; .050" gauge; 66 drive link
Bar: 160GLGK041 Pro Lite® ; K041 mount

http://www.oregonproducts.com/pro/products/combos/combo_105711.htm

thats the bar you want. nothing wrong with the BPX chain...it doesnt have the offensive drags or any of that nonsense.

 

[Chris-PA]

thats the bar you want. nothing wrong with the BPX chain...it doesnt have the offensive drags or any of that nonsense.

I really like 20BPX chain, but I'm not sure about using it on a 42cc saw - maybe with a 16" bar it would be OK. BPX in not a lo profile or narrow kerf chain, it's got tall cutters and take a good bite and will put more load on the saw.

I have a ported 46cc Poulan with the typical 20" 78DL bar. It was the first saw I ported and I went maybe just a bit too long on the intake duration - it's pretty impressive for 46cc but lately I'm realizing that the 20BPX is sometimes too much. It really depends on the wood, and if it can keep the rpm up it hauls butt with the BPX. But with other wood it's just a bit too much and it pulls the rpm down. So basically if the saw has the stones to pull it BPX will work great, but if not it may be a disappointment.

I would not want to put BPX on my fastest ported 42cc, it's much happier with 3/8 lo pro.

 

[blsnelling]

IMHO, the best chain for a 421 or MS241 would be Stihl 63PS. It's the only full chisel Picco chain on the market.

 

[Andyshine77]

I agree, 63PS all the way.





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[CoreyB]

Ok quick question why not just remove the middle piece with the cat and just use the 2 pieces vs 3?
@fordf150

 

[KenJax Tree]

Ok quick question why not just remove the middle piece with the cat and just use the 2 pieces vs 3?
@fordf150

Thats what you do. The plate the CAT in on is tack welded into the cover. Drill the tack welds and the plate falls right out and put the cover back on. You can grind out the gills on the outlet too if want.

This is a 350 but the 421 is the same.
http://www.arboristsite.com/community/threads/dolmar-350-muffler-mod.248809/

 

[CoreyB]

Thats what you do. The plate the CAT in on is tack welded into the cover. Drill the tack welds and the plate falls right out and put the cover back on. You can grind out the gills on the outlet too if want.

This is a 350 but the 421 is the same.
http://www.arboristsite.com/community/threads/dolmar-350-muffler-mod.248809/

Ya but it still looks like there are 3 pieces. Just wondering if you could just eliminate the middle or outside plate all together

 

[backhoelover]

I don't know about the true gains. Never took the time to video and time cuts on one before and after. Even without any performance gains the reduction in heat is well worth it. This saw took an extra 1/4 turn on the high side to get 13000 for break in. Don't know how it was tuned before hand though. DD tool is find a willing dealer to supply you one or ebay. There is spline, D and DD plus the pac man screw driver.

what do you do about the epoxy covered adjustment screws
plus these carbs tools lol

i got it real bad

 

[KenJax Tree]

Ya but it still looks like there are 3 pieces. Just wondering if you could just eliminate the middle or outside plate all together

Technically it is 3 pieces but when you pull the cover off its only 2, the spot welds hold the whole plate with the CAT into the cover so the only way to eliminate the CAT it to get rid of the middle plate. I don't think you could just take the CAT off and leave the plate beacause when you drill the welds the whole plate comes out of the cover.

You can't eliminate the outside because its the cover you have to get the middle plate with the CAT out that is welded into the cover.

If you took it apart you'd see exactly what im saying.

 

[CoreyB]

Technically it is 3 pieces but when you pull the cover off its only 2, the spot welds hold the whole plate with the CAT into the cover so the only way to eliminate the CAT it to get rid of the middle plate. I don't think you could just take the CAT off and leave the plate beacause when you drill the welds the whole plate comes out of the cover.

You can't eliminate the outside because its the cover you have to get the middle plate with the CAT out that is welded into the cover.

If you took it apart you'd see exactly what im saying.

Yep guess I am going to have to get one to take apart. Thanks for the explanation though. I am a bit slow sometimes.

 

[7sleeper]

subscribed!

 

[damifino]

Technically it is 3 pieces but when you pull the cover off its only 2, the spot welds hold the whole plate with the CAT into the cover so the only way to eliminate the CAT it to get rid of the middle plate. I don't think you could just take the CAT off and leave the plate beacause when you drill the welds the whole plate comes out of the cover.

You can't eliminate the outside because its the cover you have to get the middle plate with the CAT out that is welded into the cover.

If you took it apart you'd see exactly what im saying.[/QUO

The cat is attached to the middle plate. I want to drill spot welds on middle plate to remove cat and throw cat away.
Now I have original outer plate, middle plate(that cat was attached to) and inner plate.
Why can't I discard the original outer plate and make the middle plate(without cat) the new outer plate. The middle plate really is the outer chamber for the exhaust anyway and the screen is attached to the middle plate. What is the real purpose of the original outer plate anyway....no exhaust touches it.

 

[damifino]

Sorry I will try again.
The cat is attached to the middle plate. I want to drill spot welds on middle plate to remove cat and throw cat away.
Now I have original outer plate, middle plate(that cat was attached to) and inner plate.
Why can't I discard the original outer plate and make the middle plate(without cat) the new outer plate. The middle plate really is the outer chamber for the exhaust anyway and the spark screen is attached to the middle plate.
What is the real purpose of the original outer plate any way...no exhaust touches it.

 

[KenJax Tree]

Sorry I will try again.
The cat is attached to the middle plate. I want to drill spot welds on middle plate to remove cat and throw cat away.
Now I have original outer plate, middle plate(that cat was attached to) and inner plate.
Why can't I discard the original outer plate and make the middle plate(without cat) the new outer plate. The middle plate really is the outer chamber for the exhaust anyway and the spark screen is attached to the middle plate.
What is the real purpose of the original outer plate any way...no exhaust touches it.

The exhaust DOES touch it the exhaust port is on the outter cover after you pull the middle plate and CAT the exhaust goes directly out the cover through the exhaust port instead of through the CAT and then out the exhaust port.

When you pull the middle plate the CAT is attached to its gonna be all bent from prying it out.

Basically all you're doing is gutting the internal part of the outside cover so all it is is a cover with the exhaust port.