My Dolmar 7900 and Solo 681.
- Thread starter WoodChuck'r
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You guys need to play around with an 8 pin, that should help tell you which was has more grunt.
BTW great videos. Both saws sound, and look strong.
BTW great videos. Both saws sound, and look strong.
Yeah in the videos the 681 definitely seems like it's the stronger saw. But it really depends on what one would consider strong.
It could mean speed, or torque - high gear or low gear. Remember Brad talking about the perception of sound. That Solo sounds much throatier than the Dolmar. But you can't push on the 681 like you can the 7900.
Most people like speed so they would more than likely conclude that the 681 is the stronger (or "better") saw.
But it's like I said, and you basically repeated - you'd have to run them to know what kind of animal you're dealing with.
Any idea what compression is on the 7900? Not to put words in Jasha's mouth, but last I knew, he put a popup in all/most of the saws he does. The Solo does not. Matter of fact, the exhaust port was raised on that saw, also explaining the higher RPMs. Before raising the exhaust, the Solo had 190 PSI. I believe it was at 175 PSI when I shipped it. I'd be happy with that much compression in other saws with a popup and a stock exhaust port, lol. But these Solos and Dolmars seem to have a lot more compression than many others. So bottom line, I'd have to agree, that both saws are probably built for the use you intend them for. Pretty cool how it worked out that way!
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Yeah my huskys are way louder than the 7900. The 7900 is really close to cut times with the 390 though. I can lean on the 390 a little bit more than the 7900 before it starts slowing the chain speed. My 7900 has 170 lbs of compression. I would think one with a popup would be around 200.
Brad, I checked the compression on the 681 after the GTG on Sunday with Dan. I didn't check it at the best time - the saw sat for about 20 minutes, so it was still warm; but it was reading a solid 150 psi.
I don't have a compression tester, I'll use Dan's this week and check both saws when cold.
This was quoted from Jasha in my 681 thread:
BAM!! Exactly what I wanted!! :biggrinbounce2:
And yeah Brad, I'm really happy with how the saws fit right into the application I intended them for. It all worked out really nice.
I don't have a compression tester, I'll use Dan's this week and check both saws when cold.
This was quoted from Jasha in my 681 thread:
Tree Sling'r said:
BAM!! Exactly what I wanted!! :biggrinbounce2:
And yeah Brad, I'm really happy with how the saws fit right into the application I intended them for. It all worked out really nice.
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wi50
ArboristSite Operative
that's interesting, the compression numbers that is.
I ported an early Stihl 066 cylinder and made a .040" popup piston a while agoe but finally tried it out last week. Intentions are for a work saw or slipping it on one an 064 at some time. I was a little dissapointed at the compression numbers, they match my good stock parts and my new saw. But running it it's way stronger, torque is verry good. Timeing some cuts it's roughly 30-35% faster than my other 066 and 660 saws that are stock but tuned well with modded dual port mufflers, with all other things being equill.
I ported an early Stihl 066 cylinder and made a .040" popup piston a while agoe but finally tried it out last week. Intentions are for a work saw or slipping it on one an 064 at some time. I was a little dissapointed at the compression numbers, they match my good stock parts and my new saw. But running it it's way stronger, torque is verry good. Timeing some cuts it's roughly 30-35% faster than my other 066 and 660 saws that are stock but tuned well with modded dual port mufflers, with all other things being equill.
tharrison57
ArboristSite Operative
Very informative !
Great post, lots of info !
Looks like you've got a great pair to draw to !
Great post, lots of info !
Looks like you've got a great pair to draw to !
MCW
Somebody's talking crap here & it ain't the tree!
Excellent post mate. Good to see the comparo between two very similar saws modded by two good builders. I have to ask though, does this mean Brad will be getting a 7900?
I think he was sick of the poorer filtration of the 681 and wants a 7900 with a HD filter kit to play with. He's starting to come around
I don't mean to put words in your mouth Brad
I think he was sick of the poorer filtration of the 681 and wants a 7900 with a HD filter kit to play with. He's starting to come around
I don't mean to put words in your mouth Brad
Wild Knight
ArboristSite Guru
So when we gonna run 'em? Be fun to put Brad's 681 against Slingers 7900 against Ericks 441. Heck, I'll even run you guys straight up even though your running 80cc saws against my 70cc
Nik - you drivin? Andre - you bring the beer!
Nik - you drivin? Andre - you bring the beer!
I have to ask though, does this mean Brad will be getting a 7900?
I think he was sick of the poorer filtration of the 681 and wants a 7900 with a HD filter kit to play with. He's starting to come around
I don't mean to put words in your mouth Brad
No plans right now. Although I'd have a hard time passing up a good deal on a used 7900. I'd even take one with a bad top end or a 6400.
Only 150? It was reading 175 on my guage. Did you test any other saws with it?
the westspartan
Addicted to ArboristSite
Hey Brad,
It was with an Autozone compression gage and my 441 also blew a 150. I know my 441 was closer to 170 at your house. It was most likely the gage. Also we had been running them for a while and then they only sat for about a half hour or less before we comp tested them, they didn't feel real warm, but they weren't exactly cold either.
the westspartan
Addicted to ArboristSite
So when we gonna run 'em? Be fun to put Brad's 681 against Slingers 7900 against Ericks 441. Heck, I'll even run you guys straight up even though your running 80cc saws against my 70cc
Nik - you drivin? Andre - you bring the beer!
There are video links in the original post of this thread. We ran both saws and my 441 that Brad ported in the same log, 24" white pine. You might be surprised but the 441 was a couple seconds ahead of the pack on that day!, with the 681 second and the 7900 close behind. Jason posted a thread with the 441 video yesterday. I am not ready to say that my 70cc saw is faster or stronger than a 79cc and 81cc machine, but I'd say its right there with them. His were running a little more rich and mine ran a different chain (WoodlandPro Full Chisel full comp to his LGX on both of his saws) I think mine was a little sharper. His saws are beasts to be sure.
You guys should come up to the GTG on Feb. 28 at Blood on the Ice's shop in NY. It is going to be a little more of a inside, swap meet, tech type of thing I think, but he has logs and we will be cutting wood!
Yeah that's sorta what I was guessing as well.
So don't freak out if you only pull 125 PSI compression on a saw with more typical compression
BTW, a not saw will usually test about 10 PSI lower when hot.
Is there an ideal temp for checking compression??
I'm sure that it's on paper somewhere in this world. But would there actually be a difference between 50º and 70º??? I wouldn't think so, but I used to be a chairlift mechanic - even the slightest change in tolerances can make a HUGE difference...
I'm sure that it's on paper somewhere in this world. But would there actually be a difference between 50º and 70º??? I wouldn't think so, but I used to be a chairlift mechanic - even the slightest change in tolerances can make a HUGE difference...
Dang! These threads get pushed to page 3 rather quickly!!
So 45-50 would be ample temperature?? I apologize for the silly questions, I'm just tryingto get a handle on this compression thing.
Between the sh###y guages and the hundreds of opinions out there it's hard to find a clear answer....
Between the sh###y guages and the hundreds of opinions out there it's hard to find a clear answer....
