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Author Topic: 385  (Read 1357 times)

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Re: 385
« Reply #20 on: November 15, 2013, 11:36:25 pm »
Afaik, the 385 has an excellent top end, and can be improved a lot by just opening the muffler and the carb venturi, without any work on the top end.......
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Re: 385
« Reply #21 on: November 16, 2013, 06:00:35 am »
The 385 isn't giving up much of anything to the 390 with the port timing the cylinder has.
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Re: 385
« Reply #22 on: August 29, 2014, 09:43:48 pm »
How much vacuum should the crankcase hold?  Will hold around at  -.3 bar. The saw also leaks down on the pressure side as well but is within the specs in the service manual. Most stihl saw hold around -.5 bar on vacuum per there service manuals. Would it be safe to say that huskys hold the same or is -.3 bar ok?  Have a feeling I just need to find the leak and fix it. But trying to learn what the vacuum should be as I could find no spec in the 385 sm.
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Re: 385
« Reply #23 on: August 29, 2014, 11:40:29 pm »
To start with .5 bar and still have .3 bar after 30 sec is passing.
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Re: 385
« Reply #24 on: August 30, 2014, 06:25:44 am »
I can not get it to go to .5 on vacuum. Get it to .4 or so and rapidly goes down to .3 and holds there for about 15 sec than very slowy goes to like .2 3/4. I will have to find the leak.

So .5 bar on vacuum is a good number to use. And no lower than .3 in 30 seconds.
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Re: 385
« Reply #25 on: August 30, 2014, 07:05:26 am »
Vacuum test definition usually in a chainsaw repair manual . . . .

Pump down to -.5 bar or 1/2 atmosphere or 15 inches Vacuum

After 30 seconds, the crankcase should still have 60% of the vacuum or -.3 bar, 1/3 atmosphere or 9 inches.

The vacuum test is a test to determine the integrity of the seals.  The other external leaks like gasket leaks, compression release, Intake boot or insulator block, or cracks are more easily found with 1/2 atmosphere pressure and soap bubbles. It would be unusual for a chainsaw engine to hold -.5 bar and stay there forever. Don't put more than 1/2 atmosphere pressure or vacuum on the crankcase.

1/2 atmosphere pressure would be +.5bar or 7 pounds (psi) pressure. Often, you do the pressure test first. Then do the vacuum test to check the seals.
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Re: 385
« Reply #26 on: August 30, 2014, 07:14:11 am »
Thanks 660 that's what I was looking for
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Re: 385
« Reply #27 on: August 30, 2014, 07:26:23 am »
It is the flywheel side crank seal that is leaking. This is the second one with a leaking  fly side seal I have done.
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Re: 385
« Reply #28 on: August 30, 2014, 10:48:05 am »
Quote from: Gatekeeper on November 16, 2013, 06:00:35 am
The 385 isn't giving up much of anything to the 390 with the port timing the cylinder has.

According to my brother, the 385 cylinder is unusually well ported for a stock chainsaw one, and there are huge gains from opening the saw at "both ends", while leaving the cylinder alone.
I understand the 390 cylinder isn't as well ported.
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