Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Dolmar Makita => Topic started by: m_marc on January 28, 2019, 09:24:10 am

Title: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on January 28, 2019, 09:24:10 am
Hi guys,
I'm new of this forum, I'm Italian and I live in Nothern Itay near Switzerland.
I want to present you my recent project.

This autumn I decided to clean the toolshed at my granparents' house and in the middle of junk and sundries I found this:

[attachimg=1]

[attachimg=2]

It's a 1989 Dolmar Sachs 120si in bad condition (subsequently become 6800, if I'm right).
I immediately decided that it could not stay in those conditions anymore and that I would have taken some time to fix it.

I did not have much time at home so far but now it's time to start, so I decide to start this post to tell you about the restoration live.

I want to start with some information that I collect: my grandad buy this chainsaw used from a friend in 1991 (the production year could be 1988-1989) and use it for several years.
Over the years it has stopped using it because of age, in favor of lighter chainsaw for the only small jobs he do in the woodshed.
It is in toolshed unused probably by 8-9 years.
I had not found the bar when I discovered the chainsaw but now I can tell you that a week later (when I had ended clearing up the closet) it had jumped out and it is in acceptable condition.

Now some technical data:

MANUFACTURED BY: DOLMAR Maschinen-Fabrik GmbH & Co. HAMBURG, GERMANY
SERIES OR ASSEMBLY NUMBER: 120
YEAR INTRODUCED: 1987
ENGINE DISPLACEMENT: 68 cc (4.1 cu. in.)
CYLINDER BORE: 49 mm (1.93 in.)
PISTON STROKE: 36 mm (1.42 in.)
CYLINDER TYPE: Aluminum with chrome plated bore
INTAKE METHOD: Piston ported
MANUFACTURER ADVERTISED H.P.: 4.8 DIN
WEIGHT: 7.3 kg (16.09 lbs.)
HANDLEBAR SYSTEM: Anti-vibration
CHAIN BRAKE: Yes
CLUTCH: Centrifugal
DRIVE TYPE: Direct
CONSTRUCTION: Die cast magnesium
MAGNETO TYPE: Electronic
CARBURETOR: Tillotson HS-236A
AIR FILTER SYSTEM: Nylon mesh element
STARTER TYPE: Dolmar automatic rewind
OIL PUMP: Automatic, gear driven, adjustable
MAXIMUM ENGINE RPM: 8,500 under load, 12,500 free speed
IDLE RPM: 2,400
IGNITION TIMING: fixed
FLYWHEEL/COIL AIR GAP: 0.15 mm (0.038 in.)
SPARK PLUG TYPE: Bosch WSR6F
SPARK PLUG GAP: 0.5 mm (0.020 in.)
CRANKSHAFT MAIN BEARINGS: Ball
FUEL TANK CAPACITY: 700 ml (23.6 fl. oz.)
FUEL OIL RATIO: 40:1
RECOMMENDED FUEL OCTANE: Regular grade
MIX OIL SPECIFICATION: Dolmar two-cycle chain saw mix oil
CHAIN PITCH: 3/8 in.
CHAIN TYPE: Chisel
SHORTEST GUIDE BAR SUPPLIED: 40cm
LONGEST GUIDE BAR SUPPLIED: 60cm
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: Cut4fun . on January 28, 2019, 02:11:55 pm
Very cool saw. Jim here knows alot about them and I think Roger too. Maybe Bill also

@w8ye
@3000 FPS
@farmboy
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: 3000 FPS on January 28, 2019, 10:46:21 pm
Those are great strong running saws.   Worth the time to restore.     Congratulations on your saw.   
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: farmboy on January 28, 2019, 11:16:50 pm
Agree w/Roger stout saw well worth restoring.  It will make you smile.
Shep

My IPL Illustrated Parts List is to large for me to download.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: Cut4fun . on January 29, 2019, 08:33:19 am
Is this what you was wanting for IPL Shep?

Dolmar 116si 120si  siH IPL  http://download.dolmar.com/dipls/285.pdf
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on January 29, 2019, 11:02:21 am
Thank you all for the encouragement.
I'm sure it is a chainsaw that is worth bringing back into operation.

I had already found the same Part List at another link: http://www.barrettsmallengine.com/partslist/dolmarpartslist995700054.pdf

In these days the works begin, I'll try to keep you updated.
The first problem I have already seen (as you can see in the pics) it's that there isn't the hand guard anymore.
I hope that other parts of the lever and the brake are ok but I doubt it.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: farmboy on January 29, 2019, 11:20:13 pm
Is this what you was wanting for IPL Shep?

Dolmar 116si 120si  siH IPL  http://download.dolmar.com/dipls/285.pdf
Yes.  Thanks.
Shep
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: 660magnum on January 30, 2019, 12:44:37 am
In your quest for the brake parts the 116Si is the exact same saw except for the piston and cylinder.

Many parts for the 6000/6800 are the same except the brakes are different. In fact the brake mechanism is about the only thing different between the two series.

I you put a Meteor piston in it, you will find that the skirt is short about .25 mm. However, mine seems to run fine with the free porting piston.

The regular 120 Dolmar is a different saw family.

I really like my 6800iH with a 24" bar.   W8YE
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on January 30, 2019, 01:12:00 pm
Let's start!!

This morning I started to disassemble the chainsaw.
My doubts were concrete,  the hand gaurd there is not and unfortunately for me all the parts of the brake mechanism are missing, I have only the naked cover.
The engine has a good compression, the pull start works properly (I have to replace the cord) and there is a good spark.
Obviously I did not try to turn on the engine but this things that make me quiet confident.

Cleaning condition are awful, there is a solid mix of oil and sawdust encrusted in every hidden part.
Air filter is in pretty good condition, was well mounted, it is not damaged and it hasn't holes or ruptures, this is good for the health of the engine.
I separated engine from tank assemble and I have started to clean them, the rubber silent blocks are good.
Also the fly wheel is good and there is not vanes broken. Fuel hoses to the carburetor are old and stiff and brokes trying to bend it, tank was absolutely dry.
Cylinder and muffler are encrusted, muffler have some rusty points.

[attachimg=1]

From this view don't seem so bad

[attachimg=2]

From this it's worse

[attachimg=3]

Removing flywheel

[attachimg=4]

Tank collect years of sawdust and oil...

[attachimg=5]

For the first coarse cleaning I use kerosene. It melts sludge and oil very well but leave on the parts a greasy layer.
The second run of fine cleaning it's performed by Arexons Fulcron which is concentrated grease remover.

[attachimg=6]

This is the chain side cover and... I did not remove any other parts, every parts of the brake mechanism it's missing.
This afternoon I visited my trusted chainsaw shop for buy gaskets and carburetor's membranes; he still had in warehouse a complete kit for Tillotson HS-236 but I did not find a cylinder gasket (no problem, I'll make one with the old ones as a template and gasket's sheet).
For the brake assemble there aren't spare parts available and, as you rightly said, the actual 6800 differs precisely for the brake.
I talked also with the mechanic at the shop, who is old family friend (he has been working there for at least 30 years) and he told me that he will looking for. They have a warehouse of used items and parts, he is sure that there are something about Dolmar Sachs but he do not remember what. Finger crossed!!

In the next days I will continue the work.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: Cut4fun . on January 30, 2019, 02:35:45 pm
@660magnum
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on February 07, 2019, 12:23:05 pm
At the end of cleaning it does not look so bad.
I disassemble and riassemble cylinder and piston, they have a good tolerance and they are in very good condition. I riassembled with new base gasket.
Also the base bearings and needle cage are good.

[attachimg=1]

I disassembled carb and I replaced gaskets and diaphragm. I replaced also spark plug, wire and cap.

[attachimg=2]

I cleaned up and repaint muffler and mounted with new bolts.

[attachimg=3]

Dismounted, cleaned, greased and remounted oil pump. New oil hose too.

[attachimg=4]

I replaced starter rope and reassemble with fan cover and I mount the handle.

[attachimg=5]

Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: Cut4fun . on February 07, 2019, 12:51:56 pm
Looking good. Watch the Tygon on the oiler and fuel line.    Heat gets to them. If real tygon is better but if copied stuff sold as tygon is crap.

I use OEM black echo lines now.    Watch them too there is aftermarket copies of it too.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on February 07, 2019, 12:58:27 pm
Today mechanic at shop find an old used sprocket cover with complete brake assy from a 116si or 120si. I buy them for 50, I'm feel very lucky.
There's only one problem: the brake spring it's broken, several years of use worn out it.
The hand guard is good but the lever it is bended; it's not a big problem.

[attachimg=1]

[attachimg=2]

[attachimg=3]

Then, this is my idea for rebuilt the brake spring
I use a steel band; I bend them around a pipe and after that I file the parts where it overlaps (where it must be less wide).
At one extremity I bend it for fix it into the cover, at the other extremity I fix it with a pin at the part connect with the brake lever.
I don't really know if this solution works but the steel band seems strong and thicker than the original spring. We'll see...

In my hand a steel band, the same I used for rebuilt the spring.

[attachimg=4]

At the left the new spring "self-builded" compared with the old one at right (you can see the worn out extremities).

[attachimg=5]

I have not reassembled the brake in the cover yet.
For now I'm at this point, during weekend I will go on.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on February 07, 2019, 01:08:30 pm
Looking good. Watch the Tygon on the oiler and fuel line.    Heat gets to them. If real tygon is better but if copied stuff sold as tygon is crap.

I use OEM black echo lines now.    Watch them too there is aftermarket copies of it too.

Thanks for clarification.

I don't know if it is real Tygon (but I think so) but I use it for a long time and I never had problems.
On other engines even after a long time exposed to heat and fuel remains elastic and does not dry out.
I have less than a meter left at home, I remember it was quite expensive.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: Cut4fun . on February 07, 2019, 05:09:50 pm
Real will have white lettering stamped on the line TYGON and type # every few 6" or feet.  Fake wont.





Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: 3000 FPS on February 07, 2019, 10:01:21 pm
Looking good so far.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: HolmenTree on February 08, 2019, 09:51:57 am

Hi guys,
I'm new of this forum, I'm Italian and I live in Nothern Itay near Switzerland.
I want to present you my recent project.

This autumn I decided to clean the toolshed at my granparents' house and in the middle of junk and sundries I found this:

It's a 1989 Dolmar Sachs 120si in bad condition (subsequently become 6800, if I'm right).


I immediately decided that it could not stay in those conditions anymore and that I would have taken some time to fix it.

I did not have much time at home so far but now it's time to start, so I decide to start this post to tell you about the restoration live.

I want to start with some information that I collect: my grandad buy this chainsaw used from a friend in 1991 (the production year could be 1988-1989) and use it for several


It could be a late 1990-'91 by looking at the Made in Germany name tag not West Germany (1990 and older).
I used a older Sachs Dolmar 123 in the mid 1980's,  it was a quick powerhouse of a saw. I believe these saws had quad transfers which why they ran so strong plus the good muffler with oversized outlet pipe.
Husqvarna  got quad porting on a 68-70cc saw  much later on the 372XP. Not sure
 about the earlier 371XP

http://chainsawrepair.createaforum.com/index.php?action=dlattach;topic=7167.0;attach=26485;image
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: 660magnum on February 08, 2019, 10:41:14 am
Excellent clean up and restore
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on February 25, 2019, 12:02:46 pm

It could be a late 1990-'91 by looking at the Made in Germany name tag not West Germany (1990 and older).


Excellent observation.
On the brake cover that I had bought recently there is "Made in West Germany" because probably it arrives from a older chainsaw.

[attachimg=1]

I reassemble the brake system with new home made brake spring.

[attachimg=2]

At hte end I file the chain and mount it on the bar with two new very well made nuts, two nice pieces.
They have an inset that moves freely when you tighten the nut, in this way they never grind on paint.

[attachimg=3]

[attachimg=4]

[attachimg=5]

The chainsaw works perfectly, he turned on at the third shot; it only needed a carburation adjustment.
Now it needs new stickers, I plan to have them made by a graphic shop near my town, after that it will be ready for a test.

For the moment, in conclusion I'm pretty satisfied about the result and I'm glad the engine did not have big problems.
I'm very happy to have brought back an historical chainsaw.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: 660magnum on February 25, 2019, 02:45:46 pm
I'm certain you will really enjoy the 120Si as that model has been a favorite for years. And for you, the nostalgia of it being a heirloom and something you restored yourself. 
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: Bitburger on April 15, 2019, 04:33:18 pm
Dear Marco

that is a very fine job you did!
Very impressive, and the saw looks fantastic.
Why did you not just moved the working brake parts from the older lid to the original lid that you already cleaned ?
Where did you find those awesome bar nuts ? I once got a pair from my dealer, but I have never seen your version so far.

The air filter cover of your saw is already from a ps 6800, the chain brake, however, is 120si.
Both saws were told to be very common in switzerland, maybe this also holds for northern italy?

We used to spent our holidays near the city of Intra, is this close by to where you live?

Best wishes and greetings,

Christoph
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on October 17, 2019, 03:05:32 pm
Dear Marco

that is a very fine job you did!
Very impressive, and the saw looks fantastic.
Why did you not just moved the working brake parts from the older lid to the original lid that you already cleaned ?
Where did you find those awesome bar nuts ? I once got a pair from my dealer, but I have never seen your version so far.

The air filter cover of your saw is already from a ps 6800, the chain brake, however, is 120si.
Both saws were told to be very common in switzerland, maybe this also holds for northern italy?

We used to spent our holidays near the city of Intra, is this close by to where you live?

Best wishes and greetings,

Christoph

Sorry for my long absence here.

Thank you very much Cristoph,
the original lid is broken where the spring is attached, maybe for this reason in the past someone removes all the brake components.

I don't know where nuts come from, I have it at home. Maybe my father knows about that.

Dolmar Sachs are not so common in Italy, it's not so easy find spare parts and someone who knows it well.

Yes, Intra is quite close to me. Intra is on Lago Maggiore, I'm living near Lago d'Orta.
Please PM me, if you're used to spend holidays near Intra the next time will be a pleasure for me to meet you.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: m_marc on October 17, 2019, 03:17:33 pm
meantime I used the chainsaw and it works very very well.

The first idea was not use the saw at all and collect as "ornament" in my garage but I think it wouldn't have been the best thing.
This saw must be used.

In this months I had very little time and I haven't done the stickers yet, as soon as I make them I'll post a picture.

Thanks all of you for compliments I really appreciate them.
Title: Re: Dolmar Sachs 120si restoring - Picture story
Post by: pete on October 17, 2019, 07:49:29 pm
very nice work and nice to read the ending