# PS-7900 vs PS-7910



## cuttinscott (Jun 21, 2012)

Well the NEW PS-7910 are selling, and anyone that has bought them or tried them has been HAPPY. As far as NET Weight for Power Head Only as comes in the box here are the results...........

Stock Dry New PS-7900 per our digital UPS Legal scales 14.8 pounds
Stock Dry New PS-7910 per our digital UPS Legal scales 14.8 pounds


Hmmmm same weight, brattier exhaust note, NO CAT, Adjustable Carburator, 15% better on fuel, cleaner running to keep the EPA happy whats not to like??
as far as gross horsepower well I dont have a dyno But in side by side comparison cutting real Logs burring a 24" bar in hardwood 7900 vs 7910 the power and torque are very close!
The EPA Legal saw is still VERY EASY to Service, and do repairs to no major redesign to the saw..., it does have a SLR Muffler, new Cylinder with top side deco, the new lightweight piston same as late model PS-7900's New crank, new coil and a different flywheel. The carb has adjustment screws and a vent hose off the metering pump cover. So again Whats not to Like I ask?????

Both above models are less weight than the CAT equipped PS-6400 



Scott


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## nmurph (Jun 21, 2012)

You better not let Niko read that the 7910 doesn't weigh more. He was just waving that around in another thread moments ago.

Is there any chance the new coil is unlimited??? Nahh, I didn't think so...that would be too easy!


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## tdi-rick (Jun 21, 2012)

Curious what the crank differences are Scott ?

Maybe full circle or at least stuffers ?


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## Rudolf73 (Jun 21, 2012)

Thanks for the write up Scott, it's nice to finally see some 'real life' numbers.



P.S. Rick I think you should order a 7910


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## benp (Jun 21, 2012)

Thank you!!!

That's great!!


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## FATGUY (Jun 21, 2012)

cuttinscott said:


> Well the NEW PS-7910 are selling, and anyone that has bought them or tried them has been HAPPY. As far as NET Weight for Power Head Only as comes in the box here are the results...........
> 
> Stock Dry New PS-7900 per our digital UPS Legal scales 14.8 pounds
> Stock Dry New PS-7910 per our digital UPS Legal scales 14.8 pounds
> ...



limited or unlimited?


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## FATGUY (Jun 21, 2012)

tdi-rick said:


> Curious what the crank differences are Scott ?
> 
> Maybe full circle or at least stuffers ?



I'm a little confused, isn't the crank case too small already? wouldn't full circle or stuffers reduce that volume even more?


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## cuttinscott (Jun 21, 2012)

the PS-7910 coil is Limited to 12,800 in lew of the 13,500 on the PS-7900 But like I said side by side stock to stock they are VERY CLOSE I need to test with a broken in saw seeing when we tested them it was a year old 7900 vs out of box 7910. The crank is the same design I believe the timing changed and was told the crank also has been strengthened..



Scott


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## Logger4Life (Jun 21, 2012)

your killing me here what are the coil and crank differences?


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## FATGUY (Jun 21, 2012)

cuttinscott said:


> *the PS-7910 coil is Limited *to 12,800 in lew of the 13,500 on the PS-7900 But like I said side by side stock to stock they are VERY CLOSE I need to test with a broken in saw seeing when we tested them it was a year old 7900 vs out of box 7910. The crank is the same design I believe the timing changed and was told the crank also has been strengthened..
> 
> 
> 
> Scott



:mad2::mad2:

the 7900 IMHO is the greatest saw ever built. I'm glad that the 7910 has not lessened the legend, I just wish they put a coil on it that doesn't require 2 people and a big log to tune the carb...


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## benp (Jun 21, 2012)

FATGUY said:


> :mad2::mad2:
> 
> the 7900 IMHO is the greatest saw ever built. I'm glad that the 7910 has not lessened the legend, I just wish they put a coil on it that doesn't require 2 people and a big log to tune the carb...



That would make life much easier for us who struggle with tuning by ear.


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## Rudolf73 (Jun 21, 2012)

Dolmar should just install a factory tach/hr meter or a 'red light'. That would make everyone happy :msp_thumbup:


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## tallguys (Jun 21, 2012)

Just curious, is Dolmar still using a Zama carb on the 7910 or is that adjustable carb a Walbro?


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## tdi-rick (Jun 21, 2012)

FATGUY said:


> I'm a little confused, isn't the crank case too small already? wouldn't full circle or stuffers reduce that volume even more?



Who said it's too small Nik ?


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## tdi-rick (Jun 21, 2012)

tallguys said:


> Just curious, is Dolmar still using a Zama carb on the 7910 or is that adjustable carb a Walbro?



Nothing wrong with the C3M Zama on a stock saw IMO.


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## blsnelling (Jun 21, 2012)

FATGUY said:


> :mad2::mad2:
> 
> the 7900 IMHO is the greatest saw ever built. I'm glad that the 7910 has not lessened the legend, I just wish they put a coil on it that doesn't require 2 people and a big log to tune the carb...



Baaaah Humbug!!!!!!!!!!!! That limited coil in and of itself is enough to ruin that claim.


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## FATGUY (Jun 21, 2012)

tdi-rick said:


> Who said it's too small Nik ?



perhaps I have it backwards Rick, wouldn't be the first time. Remember, I only do the machine work, Brad and Andre take care of the porting...


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## tdi-rick (Jun 21, 2012)

blsnelling said:


> Baaaah Humbug!!!!!!!!!!!! That limited coil in and of itself is enough to ruin that claim.



Nothing wrong with rev limited coils if you have a decent piece of wood handy.
I have an 064 here ATM and I tuned it just like a rev limited Dolmak.

BTW, I agree with Nik, best saw evah !


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## blsnelling (Jun 21, 2012)

Hi Nik! 
























Pacer lover!


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## FATGUY (Jun 21, 2012)

Hi Brad, turn your yahoo IM on.


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## FATGUY (Jun 21, 2012)

blsnelling said:


> Hi Nik!
> 
> 
> 
> ...





blsnelling said:


> Baaaah Humbug!!!!!!!!!!!! That limited coil in and of itself is enough to ruin that claim.



you just have no taste, never have...


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## blsnelling (Jun 21, 2012)

FATGUY said:


> you just have no taste, never have...



You're right. I have no taste for Pacer chainsaws:msp_biggrin:


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## FATGUY (Jun 21, 2012)

blsnelling said:


> You're right. I have no taste for Pacer chainsaws:msp_biggrin:



but you do have an affinity for riding on the back of Harley's? :jester:


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## 166 (Jun 21, 2012)

I dug out a NOS PS-7300 Orange Top that I had new in a box for a comparison of the three color schemes for this saw.





Late Model PS-7900




The New PS-7910




PS-7910 Carburetor




PS-7910 SLR Muffler


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## Rudolf73 (Jun 21, 2012)

166 said:


> I dug out a NOS PS-7300 Orange Top that I had new in a box for a comparison of the three color schemes for this saw.
> 
> The New PS-7910



Ooooo it's got a matte black finish! :msp_wub:


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## blsnelling (Jun 22, 2012)

What is SLR?


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## benp (Jun 22, 2012)

blsnelling said:


> What is SLR?




Scavenging Losses Rejection. 

This is from the flyer that E & E posted a while back about the 2012 models.


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## SkippyKtm (Jun 22, 2012)

Seems like there would be some loss of power with the SLR system due to an overly restrictive exhaust, No?:msp_confused:


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## Miles86 (Jun 22, 2012)

Hi-

OK, so if I am understanding this right, the SLR chamber in the muffler is acting as a sonic resonator, or like an expansion chamber on a 2 stroke motocross bike?

Is this savenging loss stopped by sonic wave tuning or by physical backpressure? Thanks for the great photos.


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## tdi-rick (Jun 22, 2012)

My understanding of the new muffler is that it's a controlled bleed.

It's using backpressure from the inner chamber to reduce the scavenging losses. This then bleeds into the main body of the muffler.

It'll be interesting to see what differences there are in port timing and port sizing between the new and old jugs too.


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## SkippyKtm (Jun 22, 2012)

tdi-rick said:


> *My understanding of the new muffler is that it's a controlled bleed.*
> 
> It's using backpressure from the inner chamber to reduce the scavenging losses. This then bleeds into the main body of the muffler.
> 
> It'll be interesting to see what differences there are in port timing and port sizing between the new and old jugs too.



That's my take on it too, it reminds me of a Husky 266 I bought on CL with a plugged exhaust where the muffler itself was behaving somewhat like a primitive Dolmar chamber, except with less bleed. It would start just fine then run for about 5 seconds and quit. Then you could restart it right away once the pressure bled off and repeat the same process. I'm not saying the 7910 would run exactly that way, but I'm guessing that there is something lost there.
I hope I'm wrong, but time will tell if there is some loss in power -there's no free lunch so to speak.:msp_mellow:


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## w8ye (Jun 22, 2012)

As far as the so called bleed rates or the tuning of the muffler chamber goes, I could see it being more effective, EPA wise, at certain rpm's?


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## SawTroll (Jun 22, 2012)

nmurph said:


> You better not let Niko read that the 7910 doesn't weigh more. He was just waving that around in another thread moments ago.
> 
> Is there any chance the new coil is unlimited??? Nahh, I didn't think so...that would be too easy!



That is specs, and according to those the 7910 *is* heavier, and has .3 kW less power - but specs are specs....:msp_sneaky:

The 7910 specs are 14.7 lbs/6.7 kg and 4.3 kW/5.9 hp - the 7900 specs were about a pound less (6.3 kg) and 4.6 kW/6.3 hp.

It was well known that the weight spec of the 7900 was "optimistic", but it hardly was known that it weighted as much as Scott found.....:msp_confused:

A rev limiter at 12,800 sound really scary, what's the reason for that? :msp_scared:

Btw, my brother is very happy with his 7900 (a new Euro one) so far, except that the potential for porting is somewhat limited.....


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## Tim Carroll (Jun 22, 2012)

cuttinscott said:


> Well the NEW PS-7910 are selling, and anyone that has bought them or tried them has been HAPPY. As far as NET Weight for Power Head Only as comes in the box here are the results...........
> 
> Stock Dry New PS-7900 per our digital UPS Legal scales 14.8 pounds
> Stock Dry New PS-7910 per our digital UPS Legal scales 14.8 pounds
> ...



Thanks for posting your findings Scott, I was curious about how the new saws compared myself. I am glad Dolmar has a viable replacement for the 7300 and 7900. I was worried they would not get it figured out.


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## 166 (Jun 22, 2012)

SawTroll said:


> That is specs, and according to those the 7910 *is* heavier, and has .3 kW less power - but specs are specs....:msp_sneaky:
> 
> The 7910 specs are 14.7 lbs/6.7 kg and 4.3 kW/5.9 hp - the 7900 specs were about a pound less (6.3 kg) and 4.6 kW/6.3 hp.
> 
> ...



13.6 Pounds Original PS-7900 with Euro Small Spike Bar and no clutch cover
13.8 Pounds Original PS-7900 with large US Spike Bar and no clutch cover
14.6 Pounds Original PS-7900 with US Spike bars and clutch cover
14.8 Pounds Late model PS-7900 with US Spikes and clutch cover with minor changes and upgrades in the saw
14.8 Pounds New PS-7910 with US Spikes and clutch cover

So in real world numbers this saw has gained .2 lbs in the last 10 years.


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## Hedgerow (Jun 22, 2012)

blsnelling said:


> Baaaah Humbug!!!!!!!!!!!! That limited coil in and of itself is enough to ruin that claim.



Where's that blasted DISLIKE button!!???


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## SawTroll (Jun 22, 2012)

166 said:


> 13.6 Pounds Original PS-7900 with Euro Small Spike Bar and no clutch cover
> 13.8 Pounds Original PS-7900 with large US Spike Bar and no clutch cover
> 14.6 Pounds Original PS-7900 with US Spike bars and clutch cover
> 14.8 Pounds Late model PS-7900 with US Spikes and clutch cover with minor changes and upgrades in the saw
> ...



So the 7900 specs were without the clutch cover - that's quite disturbing.......:msp_confused:


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## redoakneck (Jun 22, 2012)

SawTroll said:


> So the 7900 specs were without the clutch cover - that's quite disturbing.......:msp_confused:




Yes, Yes it is. It is a real challenge to keep the chain tight on these dollys as the tensioner is in the cover, and when the cover isn't on I have to hold the bar out and tight when I cut, and I am running out of fingers!!! Even my friends won't hold the bar when I cut, ya just can't find good help these daze.


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## SawTroll (Jun 22, 2012)

redoakneck said:


> Yes, Yes it is. It is a real challenge to keep the chain tight on these dollys as the tensioner is in the cover, and when the cover isn't on I have to hold the bar out and tight when I cut, and I am running out of fingers!!! Even my friends won't hold the bar when I cut, ya just can't find good help these daze.


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## tdi-rick (Jun 22, 2012)

SawTroll said:


> So the 7900 specs were without the clutch cover - that's quite disturbing.......:msp_confused:



I thought I'd read on here quite a while ago (and I thought you might have mentioned it) that's how some of the manufacturers presented their 'weights' in the past ?


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## SawTroll (Jun 22, 2012)

tdi-rick said:


> I thought I'd read on here quite a while ago (and I thought you might have mentioned it) that's how some of the manufacturers presented their 'weights' in the past ?



All I remember about that is that someone claimed that Husky did it, but that wasn't true. They have made at least one mistake with not adjusting the specs when beefing up crankcases though, and no brand I know of has a perfect record regarding weight specs.....:msp_sneaky:


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## SawTroll (Jun 22, 2012)

Hedgerow said:


> Where's that blasted DISLIKE button!!???



I would have got a lot of those I guess, if that button existed!


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## 166 (Jun 23, 2012)

SawTroll said:


> So the 7900 specs were without the clutch cover - that's quite disturbing.......:msp_confused:



I explained the weight of these saws back in a thread from 2004. But that was before you were here but we had _glens_ to pick apart the specs on the 7900 back then.

http://www.arboristsite.com/chainsaw/15667-5.htm


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## 166 (Jun 23, 2012)

[video=youtube_share;TMK0jE4X9rE]http://youtu.be/TMK0jE4X9rE[/video]


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## benp (Jun 23, 2012)

166 said:


> [video=youtube_share;TMK0jE4X9rE]http://youtu.be/TMK0jE4X9rE[/video]



That'll do. :msp_thumbup:

Quite the sassy tone on that. I like it.


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## 166 (Jun 23, 2012)

benp said:


> That'll do. :msp_thumbup:
> 
> Quite the sassy tone on that. I like it.



It's quite a bit louder and has a different sound than a 7900. This saw came back from a demo today and they bought a pair of the 7910's.


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## FATGUY (Jun 24, 2012)

silly question but are there new HD filter setups that match the new matte finish covers?


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## Hedgerow (Jun 24, 2012)

166 said:


> It's quite a bit louder and has a different sound than a 7900. This saw came back from a demo today and they bought a pair of the 7910's.



What about the big saw offering???
Replacement for the 9010???


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## Andyshine77 (Jun 24, 2012)

Hedgerow said:


> What about the big saw offering???
> Replacement for the 9010???



Hum, I wonder why they beefed up the bottom end on them new 7910's?:msp_smile:


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## tdi-rick (Jun 24, 2012)

Hedgerow said:


> What about the big saw offering???
> Replacement for the 9010???





Andyshine77 said:


> Hum, I wonder why they beefed up the bottom end on them new 7910's?:msp_smile:



55mm bore with the current stroke will give 88cc, 56mm bore = 91cc..........


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## SawTroll (Jun 24, 2012)

166 said:


> I explained the weight of these saws back in a thread from 2004. But that was before you were here but we had _glens_ to pick apart the specs on the 7900 back then.
> 
> http://www.arboristsite.com/chainsaw/15667-5.htm



Yep, I remember_ glens_ wery well, and I did read on here back then! :msp_wink:


.....btw, looks like glens corrected your statement about the clutch cover back then, and the 7900 didn't weight as much as 14.8 lbs then, more like 14.4. Did the 7900 you weighted for this thread have a HD filter kit on it?

Regardess of this, the 7900 still is an interesting model, and I have surely would have had one, if I had any use for it! :msp_wink:


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## Hedgerow (Jun 24, 2012)

Andyshine77 said:


> Hum, I wonder why they beefed up the bottom end on them new 7910's?:msp_smile:



You and Rick may be on to something... But I hope it's a well thought out offering akin to the 6400/7900 jug upgrade... Not the 7900 / big bore downgrade...


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## tdi-rick (Jun 24, 2012)

Hedgerow said:


> You and Rick may be on to something... But I hope it's a well thought out offering akin to the 6400/7900 jug upgrade... Not the 7900 / big bore downgrade...




_If_ that's what is happening, you would think with the factory doing it, it will be right.

All that appeared to happen with the 54mm bore kits is that the aftermarket manufacturers took a pattern of a 52mm Mahle jug and punched it out to the bigger bore, restricting transfer volume/size at the same time.


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## benp (Jun 24, 2012)

Andyshine77 said:


> Hum, I wonder why they beefed up the bottom end on them new 7910's?:msp_smile:





tdi-rick said:


> 55mm bore with the current stroke will give 88cc, 56mm bore = 91cc..........





Hedgerow said:


> You and Rick may be on to something... But I hope it's a well thought out offering akin to the 6400/7900 jug upgrade... Not the 7900 / big bore downgrade...





tdi-rick said:


> _If_ that's what is happening, you would think with the factory doing it, it will be right.
> 
> All that appeared to happen with the 54mm bore kits is that the aftermarket manufacturers took a pattern of a 52mm Mahle jug and punched it out to the bigger bore, restricting transfer volume/size at the same time.



Forgive my ignorance, but are you guys saying that the bottom end on the 7910 is overbuilt for it's current application?

If so I have seen this before...in snowmobiles. 

When Arctic Cat came out with it's ZR800 twin, the bottom end was bullet proof. It didn't make sense that that kind of upgrade would be made for that motor unless........something bigger was coming down the line. 

Sure enough, a little later, the ZR900 emerged on the same bottom end. Aaaaand that same bottom end was used for some ridiculous big bore motors. 

Anyways, I digress, very intredasting though. Would be fun to have a 90cc saw in the size of the 64/73/79xx series saw.


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## tdi-rick (Jun 24, 2012)

benp said:


> Forgive my ignorance, but are you guys saying that the bottom end on the 7910 is overbuilt for it's current application?
> 
> If so I have seen this before...in snowmobiles.
> 
> ...




Ben, the Dolmar dealers on here have been saying that a new 90+cc saw is coming to replace the PS9010, so we are just indulging in a little speculation


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## benp (Jun 24, 2012)

tdi-rick said:


> Ben, the Dolmar dealers on here have been saying that a new 90+cc saw is coming to replace the PS9010, so we are just indulging in a little speculation



LOL - I just giggled like a school girl when I read that. 

That would be really really cool. 

I better start saving now, everyone needs a backup 90+, especially if Dolmar is able to successfully pull it off in that chassis.


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## SawTroll (Jun 24, 2012)

Hedgerow said:


> You and Rick may be on to something... But I hope it's a well thought out offering akin to the 6400/7900 jug upgrade... Not the 7900 / big bore downgrade...



I (really my brother) agree that the 84cc BB kits are a major downgrade on the 7900, unless they are extensively modded - and they can't be ported anywhere close to ideal anyway, too little material in important places. Stock (OEM) 7900 is much better, but still has some limitations, regarding porting.


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## Hedgerow (Jun 24, 2012)

benp said:


> LOL - I just giggled like a school girl when I read that.
> 
> That would be really really cool.
> 
> I better start saving now, everyone needs a backup 90+, especially if Dolmar is able to successfully pull it off in that chassis.



I may make it up to Specter's gtg in northern WI this August... I got a dandy 9010 for ya to run... Built like a tank and power to spare... VERY sexy saw...:msp_sneaky:


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## angelo c (Jun 24, 2012)

tdi-rick said:


> Who said it's too small Nik ?



ummm errrr ummmm don't do it...don't say it....


My self control classes are working so well lately.....i was so close but managed to not say it...


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## Andyshine77 (Jun 24, 2012)

tdi-rick said:


> Who said it's too small Nik ?



I think Nik misspoke when he said too small, he meant the case is smaller than most saws of that size. I personally haven't measured the case volume of the Dolmar, I'm just going by what others that I trust have said.


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## parrisw (Jun 25, 2012)

That new saw sounds really good.


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## spike60 (Jun 25, 2012)

Sounds like this new 7910 might be a good excuse for another GTG up at The Cutting Edge, eh?


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## 166 (Jun 25, 2012)

spike60 said:


> Sounds like this new 7910 might be a good excuse for another GTG up at The Cutting Edge, eh?



Have you tried out the demo 7910 that Bob has?


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## spike60 (Jun 25, 2012)

166 said:


> Have you tried out the demo 7910 that Bob has?



Not yet. Haven't seen him since he got it. He's happy with though. Good power right out of the box, and compared well with a broken in 7900. A little time on the 7910 and I'd say they'll be neck and neck.

I like how Dolmar came up with an innovative solution to make a great chassis compliant, rather than have to do a clean sheet strato design. Is there a chance that they could use this controlled bleed muffler idea to replace the cat on saws like the 5105? The heat from those things is not good for any saw.


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## 166 (Jun 25, 2012)

spike60 said:


> Not yet. Haven't seen him since he got it. He's happy with though. Good power right out of the box, and compared well with a broken in 7900. A little time on the 7910 and I'd say they'll be neck and neck.
> 
> I like how Dolmar came up with an innovative solution to make a great chassis compliant, rather than have to do a clean sheet strato design. Is there a chance that they could use this controlled bleed muffler idea to replace the cat on saws like the 5105? The heat from those things is not good for any saw.



They came out with the SLR cylinder/muffler on the cut off saws first. I'm sure they are working on this design on other models. But they do have strato model chainsaws in the works. It is nice to share the majority of parts with the 7900. Especially on a saw that gets beat up and crashed a lot.

We have had Zero issues with the cat mufflers on the 350/351/420/421/510/5105/6400/7335 (Cut Off) other than burning off the foil insulation on the cylinder cover.


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## 166 (Jun 25, 2012)

spike60 said:


> Sounds like this new 7910 might be a good excuse for another GTG up at The Cutting Edge, eh?



Maybe a mini GTG at Boonville?


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## thechainsawguy (Jul 26, 2012)

*Opening the muffler*

So what would opening up the muffler do? Or replacing it with an earlier 7900 muffler? I guess it would need to be richened on the jets.

Has anyone done this? I guess its basically the same as the original 7900?

Thanks Dave.


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## Hedgerow (Jul 26, 2012)

thechainsawguy said:


> So what would opening up the muffler do? Or replacing it with an earlier 7900 muffler? I guess it would need to be richened on the jets.
> 
> Has anyone done this? I guess its basically the same as the original 7900?
> 
> Thanks Dave.



That sir, is a good question...
I'm hoping to find out some info in a couple weeks...


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## thechainsawguy (Jul 26, 2012)

Hedgerow said:


> That sir, is a good question...
> I'm hoping to find out some info in a couple weeks...




I have a customers saw here that wants the extra muffler port, so I want to find out if I would be upsetting anything by messing with the new system. 

Dave


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## Hedgerow (Jul 27, 2012)

thechainsawguy said:


> I have a customers saw here that wants the extra muffler port, so I want to find out if I would be upsetting anything by messing with the new system.
> 
> Dave



You got a test log? If so, run it through... Give it an extra port, and compare... Then let us know... Worst case scenario, you gotta order another muffler...
Best case, it improves performance...
Something tells me there's not much to be gained there... But I could be wrong...


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## thechainsawguy (Jul 27, 2012)

Hedgerow said:


> You got a test log? If so, run it through... Give it an extra port, and compare... Then let us know... Worst case scenario, you gotta order another muffler...
> Best case, it improves performance...
> Something tells me there's not much to be gained there... But I could be wrong...




I will try that, I happen to have dual port 7900 muffler here right now, so I will just swap it out and see, Dave


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## Hedgerow (Jul 27, 2012)

thechainsawguy said:


> I will try that, I happen to have dual port 7900 muffler here right now, so I will just swap it out and see, Dave



Please let us know.... I hope I'm wrong about my theory... Since I would like a new 7910. The existing 7900 will be going under the grinder soon...


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## thechainsawguy (Jul 27, 2012)

Hedgerow said:


> Please let us know.... I hope I'm wrong about my theory... Since I would like a new 7910. The existing 7900 will be going under the grinder soon...




Will do, but whats your theory.....

Dave.


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## Hedgerow (Jul 27, 2012)

thechainsawguy said:


> Will do, but whats your theory.....
> 
> Dave.



That The engineers at Dolmar have figured out how to make a small expansion chamber inside the muffler of their saw... Reducing emissions while not hindering performance of the saw...
If so, you'll get a net gain of zero... Possibly a decrease in performance...


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## thechainsawguy (Jul 31, 2012)

*Dolmar 7910 Carb*

So I went to look at the 7910's new carb before I put the 7900 dual port muffler on to test. I see the highspeed is not adjustable with a screwdriver. I call up Dolmar and ask for the special tool needed to richen the carb and they tell me that we are not allowed by epa to have them.......


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## Andyshine77 (Jul 31, 2012)

You should be able to get the tool from a dealer.


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## thechainsawguy (Jul 31, 2012)

Andyshine77 said:


> You should be able to get the tool from a dealer.



I AM a dealer....lol. This is what my distributer just told me.


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## Hedgerow (Jul 31, 2012)

These?
carb adjusting tools | eBay


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## Rudolf73 (Jul 31, 2012)

Rats! the EPA are at it again :bang:


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## Hedgerow (Jul 31, 2012)

Or these?
Craftsman Walbro Zama 530035560 carb adjustment tool | eBay


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## Hedgerow (Jul 31, 2012)

Rudolf73 said:


> Rats! the EPA are at it again :bang:



They're not as smart as they think...
:canny:


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## thechainsawguy (Jul 31, 2012)

Hedgerow said:


> These?
> carb adjusting tools | eBay



It could be, I have never had anything in the shop that needed one before.

Dave.


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## Andyshine77 (Jul 31, 2012)

thechainsawguy said:


> I AM a dealer....lol. This is what my distributer just told me.



I was wondering about that Are the needle heads Splined, Double D, Single D? Chainsaw / Weedeater Carburetor Adjustment Tool Set


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## Hedgerow (Jul 31, 2012)

thechainsawguy said:


> It could be, I have never had anything in the shop that needed one before.
> 
> Dave.



You may want to get a set... Sure beats taking them all the way out and cutting a groove in em' with a hacksaw...

Don't ask...
:msp_rolleyes:


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## Andyshine77 (Jul 31, 2012)

Hedgerow said:


> You may want to get a set... Sure beats taking them all the way out and cutting a groove in em' with a hacksaw...
> 
> Don't ask...
> :msp_rolleyes:



I did just that on my $20 WT.:msp_biggrin:


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## thechainsawguy (Jul 31, 2012)

Andyshine77 said:


> I was wondering about that Are the needle heads Splined, Double D, Single D? Chainsaw / Weedeater Carburetor Adjustment Tool Set



It just looks like a bare stud sticking out, but I can't see it well, it may be splined. Will have to pull the carb off for a better look.

Dave.


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## Hedgerow (Jul 31, 2012)

thechainsawguy said:


> It just looks like a bare stud sticking out, but I can't see it well, it may be splined. Will have to pull the carb off for a better look.
> 
> Dave.



Should be a Zama right? 
Splined I'll bet...
The beauty of those is, once set, put the limiters back on, and the EPA dorks are none the wiser...
Think of it as "civil dis-obedience"...:msp_wink:


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## 166 (Jul 31, 2012)

Andyshine77 said:


> I was wondering about that Are the needle heads Splined, Double D, Single D? Chainsaw / Weedeater Carburetor Adjustment Tool Set



They have a Double D on the HS Needle. Regular Screwdriver for the LS needle.



Hedgerow said:


> Should be a Zama right?
> Splined I'll bet...
> The beauty of those is, once set, put the limiters back on, and the EPA dorks are none the wiser...
> Think of it as "civil dis-obedience"...:msp_wink:



No limiter caps at all on these saws.


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## Hedgerow (Jul 31, 2012)

166 said:


> They have a Double D on the HS Needle. Regular Screwdriver for the LS needle.
> 
> 
> 
> No limiter caps at all on these saws.



Cool!!! This is why they pay you the big bucks...


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## WoodChuck'r (Jul 31, 2012)

Interesting read on this thread for sure.


The new 79'er sounds bada$$. Definitely gotta put one on my list. 


I'm down to only 6 saws now, eventually I gotta get some more pigs in the pen.


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## Hedgerow (Jul 31, 2012)

WoodChuck'r said:


> Interesting read on this thread for sure.
> 
> 
> The new 79'er sounds bada$$. Definitely gotta put one on my list.
> ...



Mods???


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## wendell (Jul 31, 2012)

WoodChuck'r said:


> I gotta get some more pigs in the pen.



Bacon


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## nstueve (Aug 1, 2012)

Andyshine77 said:


> Hum, I wonder why they beefed up the bottom end on them new 7910's?:msp_smile:


if they did beef up the bottom I wonder how long it takes for them to come out with the 90cc version... Then how long will it take for someone to put the 90cc P&C on a non-beefed older bottom end and blow it up???



Hedgerow said:


> I may make it up to Specter's gtg in northern WI this August... I got a dandy 9010 for ya to run... Built like a tank and power to spare... VERY sexy saw...:msp_sneaky:


:arg:
ooooh ooooh!!! pretty blue or dolmar red/orange??? What mods did you do? I'm about to put my 9010 back together when I get some free time...



thechainsawguy said:


> So I went to look at the 7910's new carb before I put the 7900 dual port muffler on to test. I see the highspeed is not adjustable with a screwdriver. I call up Dolmar and ask for the special tool needed to richen the carb and they tell me that we are not allowed by epa to have them.......



interested to hear what the results are on the muff swap...


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## Hedgerow (Aug 1, 2012)

:arg:
ooooh ooooh!!! pretty blue or dolmar red/orange??? What mods did you do? I'm about to put my 9010 back together when I get some free time...



Dolmar orange and black... The work that has been done to it is a mystery... It does have a nice dual port cover...:msp_sneaky:


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## Chris J. (Aug 1, 2012)

thechainsawguy said:


> I will try that, I happen to have dual port 7900 muffler here right now, so I will just swap it out and see, Dave



I'm about to look like a complete idiot (not for the first or last time), but here goes:

Since the 7910 has the new SLR muffler, wouldn't you need to mod the SLR muffler to test how it responds to mods, instead of using a non-SLR 7900 muffler?

Or are you just wanting to see how the 7910 responds in general with a more opened muffler?

I'm probably misunderstanding something, and not being clear with my post .


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## thechainsawguy (Aug 1, 2012)

I think the SLR system is all in the muffler, but I will need the screwdriver to richen up the high speed if I am going do the muffler swap. I have ordered the 4 tools to do this. I never needed them until now. I am going to borrow one locally so I can try it sooner. I have no idea why Dolmar Canada said you can't have the tool. They made it seem only the factory has them. I would have to be able to richen this saw up if I lived near the 4000 foot level.

Dave.


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## Hedgerow (Aug 1, 2012)

thechainsawguy said:


> I think the SLR system is all in the muffler, but I will need the screwdriver to richen up the high speed if I am going do the muffler swap. I have ordered the 4 tools to do this. I never needed them until now. I am going to borrow one locally so I can try it sooner. I have no idea why Dolmar Canada said you can't have the tool. They made it seem only the factory has them. I would have to be able to richen this saw up if I lived near the 4000 foot level.
> 
> Dave.



Does this 7910 have the rev limited coil?


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## WoodChuck'r (Aug 15, 2012)

Hedgerow said:


> Mods???




Meh, prolly not.....


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## Hedgerow (Aug 15, 2012)

WoodChuck'r said:


> Meh, prolly not.....



I ran one in WI last week... Brand new though and not broke in... Nice saw, but less power than the 7900. I'm sure folks will find a way around that...


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## WoodChuck'r (Aug 15, 2012)

Hedgerow said:


> I ran one in WI last week... Brand new though and not broke in... Nice saw, but less power than the 7900. I'm sure folks will find a way around that...




I'm sure they're nice. Less power....? Yeah that's more than likely too. I'm sure it's a powerhouse though. I have less of a desire to have everything ported anyways - with a ported XPW and my 039 I'm happy as could be and I'd prolly be just as happy with a stock 7910'er in the pen....


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## Hedgerow (Aug 15, 2012)

WoodChuck'r said:


> I'm sure they're nice. Less power....? Yeah that's more than likely too. I'm sure it's a powerhouse though. I have less of a desire to have everything ported anyways - with a ported XPW and my 039 I'm happy as could be and I'd prolly be just as happy with a stock 7910'er in the pen....



I understand that...
I ran your 371 in sconnie last week...
It's pretty snotty...
:msp_sneaky:


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## SawTroll (Aug 15, 2012)

Hedgerow said:


> I ran one in WI last week... Brand new though and not broke in... Nice saw, but less power than the 7900. I'm sure folks will find a way around that...



That's consistent with the specs, so no surprice. :msp_wink:


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## WoodChuck'r (Aug 15, 2012)

Hedgerow said:


> I understand that...
> I ran your 371 in sconnie last week...
> It's pretty snotty...
> :msp_sneaky:





That's what I hear. :msp_thumbsup:


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## Hedgerow (Aug 15, 2012)

SawTroll said:


> That's consistent with the specs, so no surprice. :msp_wink:



But the sideways balance of it was superb...
:msp_biggrin:


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## Eccentric (Sep 5, 2012)

So........has anyone ran a 7910 with a 'modified' SLR muffler yet? It's been a few weeks since this was last discussed in this thread.opcorn:


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## SawTroll (Sep 5, 2012)

Eccentric said:


> So........has anyone ran a 7910 with a 'modified' SLR muffler yet? It's been a few weeks since this was last discussed in this thread.opcorn:



The only thing I know about that, is that the power spec is down by .3 kW/.4 hp, which is consistent with the obviously added "blowback" from a muffler like that - and now is lower than for the MS460 and 461, rather than higher.


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## B Harrison (Apr 19, 2013)

SO was this ever settled?

Is a MM 7910 an improvement, does the chamber take much power to give economy?
I am wondering, is a second port the way to go on mm for 7910, obviously easier than opening up the first if not removing the inserted round pipe.

If so who has dual ported there 7910 muff?


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## retoocs555 (Apr 19, 2013)

Can't speak to the muffler mod question, we haven't seen much room for improvement with the stock SLR muffler.

I can say, that we have had these 7910s for almost a year now, and have near 50 of them out being professionally used in this area now.

The 7910 is in for repairs much less often than the 7900s were. I LOVE the new carbs. Easy to set and they tend to stay that way once we dial them in.

For use limbing and cutting smaller softwood the 7900 was/is faster than a 7910.

In a big block of maple the 7910 will out lug the stock 7900 and is faster by a whisker. Faster than stock MS460 and 390xp too, but I'm not here to get into that discussion.


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## tdi-rick (Apr 19, 2013)

What model Zama is the new carby ?

I'm too lazy to download an IPL


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## Hedgerow (Apr 19, 2013)

retoocs555 said:


> Can't speak to the muffler mod question, we haven't seen much room for improvement with the stock SLR muffler.
> 
> I can say, that we have had these 7910s for almost a year now, and have near 50 of them out being professionally used in this area now.
> 
> ...



That's actually good info...
Thank you....


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## nstueve (Apr 19, 2013)

I'm hearing whispers in the wind that there will be a brand new 7910 at the Iowa GTG and will be going to Shaun Carr's shop for "improvements." I might poke him and see if he won't make a thread or post here the results he got. I'd like to see 4 stages in timed cuts. 

1.) Stock
2.) muffler mod and carb adjustment
3.) traditional intake and exhaust port (no timing change but set squish at .019-.021)
4.) full blown squish band cut and porting of the whole saw... (shaun's "INFINITY" porting)


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## B Harrison (Apr 20, 2013)

Good deal, the retainer that holds the clutch and rim sprocket on broke on mine (muddy stumps, termites and dirt) and I want to mod the oiler for more flow with a 36" bar, but strong saw.


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