Quick Dolmar question here

[Lawn Masters]

How fast should a 120 Si be with an 8T rim 16" bar 3/8 .050 semi chisel chain be with the rakers set at .030? I ran mine today in some long dead, and dried oak, about 12" around, it took about 20 seconds to cut through the log. I could have my carb set too rich, which knowing me is quite possible. I do like this thing for a saw, could be lighter, but I wont complain too much.

 

[Molecule]

sounds definitely slow ... do you have compression ... is the clutch slipping ... is the bar groove shot (giving sloppy support for the chain) ... the 030 rakers might be a little steep for a 24" bar, but you're only cutting 12" ... does the chain pull the saw in to the log like it should ... with my 6800 with new piston and clutch, and 025 rakers, there is a *very *definite pull toward the wood. In fact, the saw almost won't let you cut mid-bar ... I hadn't thought about it, but it takes too much effort to hold it back off the wood.

 

[rmihalek]

Hi OSaddict,

Here're my results (Bob M) with a stock 119 cutting in 10 inch (?) diameter beech at Jokers gathering.

0-60cc 2 cuts
Don 18.95 sec.
Russ C. 11.85 sec.
Lewis 24.9 sec
Frank W 11.69 sec
Brain w 11,07 sec
Paul W 6.65 sec
Sedanman 13.02 sec
Bob M 14.48 sec
Rich H. 9.26 sec
Ed H 6.52 sec
Brent D 20.68 sec
Eric C 6.87sec
Larry C 8.87 sec
Chris C 10.97 sec

 

[Lawn Masters]

sounds definitely slow ... do you have compression ... is the clutch slipping ... is the bar groove shot (giving sloppy support for the chain) ... the 030 rakers might be a little steep for a 24" bar, but you're only cutting 12" ... does the chain pull the saw in to the log like it should ... with my 6800 with new piston and clutch, and 025 rakers, there is a *very *definite pull toward the wood.

I just put a whole new piston in it, and rings, and the clutch isnt slipping, unless I lean on the saw. I'm only running a 16" not a 24" bar though. the rails are in good shape and it does pull the saw into the wood. its just slow. maybe I'll put the 20" bar and some chisel chain on it then see how it does.

Thanks for the times and suggestions.

 

[Lewis Brander]

Question:

OSA. Don't take this to heart. Sort of a Joke question. But is your chain on right? Ha, just had to ask. Guess I'm getting old and synical. Take care. Lewis.

 

[TonyM]

O-A, that doesn't sound good. That's over a 5 Hp saw. My 115si is cutting 8" Locust in roughly 4 seconds. The PS7900 is doing the same cut in a tad over 2 seconds. This is with square filed chisel chain. Something's not quite right. Is the saw bogging down in the cut? I wonder if an 8T in combination with .030 rakers might be a tad much. How is the compression? Maybe that new ring needs a little break in time yet. Is the saw getting up to RPM's and four stroking a little at WOT no load? Wish I could I be there in person to help you out. That should be a kick butt saw.

 

[sedanman]

My 120si held better engine rpm with a 7 tooth sprocket.

 

[Mange]

Here Robert is my best shot:

The carbs settings! It is possible you have the "H" in too long and overcompensate with "L", This way it really get too little fuel, but sounds ok.
I would do a reset, and make sure, if nothing else just to rule it out.

How did it run, rpm's, power, hickups, did the rpm's fall in the cut, if so when?

Dry oak is a bit tricky at times, as are dry elm, what did the chips look like?

Hope it helps.

 

[Lawn Masters]

The chips from the saw are normal looking, I tend to think its the carb settings, and maybe I need to run more fuel through it yet. I probably should go to the 7t sprocket too.

 

[SawTroll]

That sounds sensible to me!

 

[sedanman]

It's also possible that you repaired the damage but not the cause of the original failure. The conditions that toasted the previous piston may still exist.

 

[Lawn Masters]

I know what wrecked the original piston, something got sucked into the saw, and jammed between the piston and the exhaust port.

 

[Lawn Masters]

Alright guys, thanks for the help, I tried the 3/8x 7t rim today, it made a world of difference. along with some round chisel chain having the rakers at .025 instead of .030 as my semi chisel is. it could still be faster, but that will change when everything is broken in, and I've run another 10 tanks of gas through it. sure is nice to have a saw that doesnt suck.

 

[TonyM]

Whew, you had me worried. So it looks like everything's going to be okay after all?

 

[Lawn Masters]

Yep.

 

[Stumper]

OSA, Breakin may make a world of difference. My 120si absolutely smokes my Power Ported 7900 in 20 inch hardwood.

 

[TonyM]

OSA, Breakin may make a world of difference. My 120si absolutely smokes my Power Ported 7900 in 20 inch hardwood.

Huh?

120SI faster than a ported 7900? Ported by whom?

How can a 6.3Hp stock saw be outcut by a 5.1 Hp stock saw? The 120si's I've run were good saws, but no match for a stock 7900.

 

[Stumper]

The 7900 was ported by Dan Henry. It is a fine saw. Just to clarify. Both saws are running 8 pin sprockets. The 7900 has a 28 inch bar and is running skip, rnd ground chisel. The 120si has a 20 inch bar and is running normal compliment rnd ground chisel (I have also run skip on it with similar speed). I do not know the history on the 120si-I bought it used. The seller said it was a firewood saw trade in-who knows but it is FAST. I may be running the 7900 a little too rich- the electonic governor interferes with tuning by ear but it does pull chain pretty well. My old Husky 281xp with muffler mods and 7pin spocket 34 " bar pretty well keeps up with the 7900 in 24" and over wood but is slower in small stuff.

 

[Lawn Masters]

How a 120 can outcut a 7900, I'll never know. put square chisel on both of them, and a 20" bar, same pitch, gauge, and sprocket size, and time em.

 

[TonyM]

The 7900 was ported by Dan Henry. It is a fine saw. Just to clarify. Both saws are running 8 pin sprockets. The 7900 has a 28 inch bar and is running skip, rnd ground chisel. The 120si has a 20 inch bar and is running normal compliment rnd ground chisel (I have also run skip on it with similar speed). I do not know the history on the 120si-I bought it used. The seller said it was a firewood saw trade in-who knows but it is FAST. I may be running the 7900 a little too rich- the electonic governor interferes with tuning by ear but it does pull chain pretty well. My old Husky 281xp with muffler mods and 7pin spocket 34 " bar pretty well keeps up with the 7900 in 24" and over wood but is slower in small stuff.

Okay, that makes sense. I'm sure if you ran the same B/C setup on both saws, the 7900 would pull away convincingly.