B_Turner
Addicted to ArboristSite
I kind of have a saw habit, and in reading what most folks have said about the Dolmar 7900 I went out a couple of days ago and bought new one of the bubble saws to try it out for myself.
(I'll admit up front that I am a really fussy guy when it comes to my equipment.)
The chain tensioner on my new 7900 is terrible and after reading posts from over a year ago about this problem, I figured that Dolmar must have fixed it by now. The manufacturing date on my new saw is about 14 months ago (even though my dealer had to order the saw for me) and here's the question in my post:
** Anyone know if Dolmar has come out with a update to that sticky chain tensioning mechanism during the last year? I would love to replace it if so.
I examined it at length and think the engineering is poor in regard to the gear and spline for that application. I think the right engineer could improve it in a heartbeat. Maybe even just a finer toothing.
I've got a number of hours using and fiddling with the saw and for what it's worth here's my impression so far for anyone interested:
Cons:
* The design under the sproket cover doesn't clear the long shavings (noodles, as Sam Madsen calls them) well. Worse than any of my other saws in that regard. I'll spare the detail why. Works fine for normal crosscutting, which it has been optimized for..
* The chain tensioner is funky and Dolmar engineers should be ashamed. Sticks and awkward. Took it apart and greased it several times to no avail. With the right fiddling and wiggling the bar it will eventually tighten, but not ready for prime time.
* I run REALLY sharp chains, so I don't sharpen on the saw (I bring a bag of chains to the site). So I swap chains pretty often and I find the 7900 tensioner design very akward with the tensioner's bar locating pin on the cover instead of the saw body. Nothing to hold the bar and chain in place once the cover is off and more difficult to see where to adjust the tensioner when putting on a chain of a different length. Most folks sharpen on the saw, so that is not a problem for them.
* So far it smokes a bit more than any other of my saws using the same mix (50:1 Stihl). It is not running rich, and I am hoping it miraculously clears up over time. Suggestions?
* Cheesy chaincatcher compared to Huksy or Stihl of this size, but no biggie.
Pros:
*Great weight for it's size. Feels about the same as my 371 in the hand. Decent balance.
*Much smoother than my 066 although not as quite as smooth as my 395. But acceptable to me and I am a fanatic regarding saw smoothness because of the kind of cutting I do. So I say pretty good here.
*Starts great.
**Heres the kicker: This is a really fun motor to run. Peppy, great throttle response, strong and even power. I can see why people like them. I usually have about 4 saws out at a time, and I keep wanting to pick the bubblesaw up. Just plain satisfying, just like certain motorcycles that for some reason just kind of make you feel good.
The airfilter looks too small, but at least now when it's clean it seems to be making plenty of power. For the kind of cutting I do I'm still not decided on whether I would buy it again, but for the normal crosscutting the bubblesaw with a squareground chisel chain is pretty impressive. But even in the Seattle area it was like pulling teeth to find a dealer to buy one from.
(I'll admit up front that I am a really fussy guy when it comes to my equipment.)
The chain tensioner on my new 7900 is terrible and after reading posts from over a year ago about this problem, I figured that Dolmar must have fixed it by now. The manufacturing date on my new saw is about 14 months ago (even though my dealer had to order the saw for me) and here's the question in my post:
** Anyone know if Dolmar has come out with a update to that sticky chain tensioning mechanism during the last year? I would love to replace it if so.
I examined it at length and think the engineering is poor in regard to the gear and spline for that application. I think the right engineer could improve it in a heartbeat. Maybe even just a finer toothing.
I've got a number of hours using and fiddling with the saw and for what it's worth here's my impression so far for anyone interested:
Cons:
* The design under the sproket cover doesn't clear the long shavings (noodles, as Sam Madsen calls them) well. Worse than any of my other saws in that regard. I'll spare the detail why. Works fine for normal crosscutting, which it has been optimized for..
* The chain tensioner is funky and Dolmar engineers should be ashamed. Sticks and awkward. Took it apart and greased it several times to no avail. With the right fiddling and wiggling the bar it will eventually tighten, but not ready for prime time.
* I run REALLY sharp chains, so I don't sharpen on the saw (I bring a bag of chains to the site). So I swap chains pretty often and I find the 7900 tensioner design very akward with the tensioner's bar locating pin on the cover instead of the saw body. Nothing to hold the bar and chain in place once the cover is off and more difficult to see where to adjust the tensioner when putting on a chain of a different length. Most folks sharpen on the saw, so that is not a problem for them.
* So far it smokes a bit more than any other of my saws using the same mix (50:1 Stihl). It is not running rich, and I am hoping it miraculously clears up over time. Suggestions?
* Cheesy chaincatcher compared to Huksy or Stihl of this size, but no biggie.
Pros:
*Great weight for it's size. Feels about the same as my 371 in the hand. Decent balance.
*Much smoother than my 066 although not as quite as smooth as my 395. But acceptable to me and I am a fanatic regarding saw smoothness because of the kind of cutting I do. So I say pretty good here.
*Starts great.
**Heres the kicker: This is a really fun motor to run. Peppy, great throttle response, strong and even power. I can see why people like them. I usually have about 4 saws out at a time, and I keep wanting to pick the bubblesaw up. Just plain satisfying, just like certain motorcycles that for some reason just kind of make you feel good.
The airfilter looks too small, but at least now when it's clean it seems to be making plenty of power. For the kind of cutting I do I'm still not decided on whether I would buy it again, but for the normal crosscutting the bubblesaw with a squareground chisel chain is pretty impressive. But even in the Seattle area it was like pulling teeth to find a dealer to buy one from.
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