Husky 444 top end

[samarsenault]

Hi. I'm pretty new to this game and could use some help. Here's the story:

Started cutting with my dad's husqvarna 444 which is probably 20+ years old. Got partway through a cut and the saw died at full throttle. There was still spark and fuel and the pull cord was MUCH easier to pull than usual.

I need to fix this as cheaply as possible because I don't have a big saw budget. A good friend's father owns a local small engine shop and was formerly a husqvarna dealer. He told me to take the cylinder off and bring it in to show him so I did. He said the cylinder itself is in great shape, the piston is just fair (a few scuffs) and the ring was stuck. I went home and removed the ring and gently used a knife to fix up the part of the ring groove it had stuck on as per mechanic's instruction.

He also pointed out that the piston was not pivoting on the connecting rod as smooth as it should and said i better take the bearing out too. I removed the two clips holding the pin in and tapped the pin out and the bearing fell out - in about two dozen little pieces.

I called the local husky dealer and he has the bearing and the ring in stock for less than 30 bucks total. Is this as simple to put back together as it was to take appart and better yet what caused the bearing to go and the ring to stick?

This is my first engine rebuild so no advice is too simple for me right now. Also cost is of the essence. My friend's dad said if the saw was for pro use he would definately put a new piston but if I'm interested in saving the money the old one should work fine for me as I only cut about 2 cords/year.

 

[RED-85-Z51]

ENGINE DISPLACEMENT:
44cc (2.68 cu. in.)
NUMBER OF CYLINDERS:
1
CYLINDER BORE:
42mm (1.654 in.)
PISTON STROKE:
32mm (1.260 in.)
CYLINDER TYPE:
Aluminum with chrome plated bore
INTAKE METHOD:
Piston ported
MANUFACTURER ADVERTISED H.P.:

WEIGHT :
6 kg with 32 cm bar & chain
OPERATOR CONFIGURATION:
One Man operation
HANDLEBAR SYSTEM:
Anti-vibration
CHAIN BRAKE:
Mechanical
CLUTCH:
Centrifugal
DRIVE TYPE:
Direct
CONSTRUCTION:
Die cast magnesium
MAGNETO TYPE:
Electronic
CARBURETOR:
Walbro HDC type
MAJOR REPAIR KIT:
K10-HDC
MINOR REPAIR KIT:
D10-HDC
AIR FILTER SYSTEM:
Nylon mesh cartridge
OIL PUMP:
Automatic, adjustable
OPERATING RPM:
9,000
FLYWHEEL/COIL AIR GAP:
0.3 mm (0.012 in.)
SPARK PLUG TYPE:
Bosch WS7F
SPARK PLUG GAP:
0.5mm (0.020 in.)
CRANKSHAFT MAIN BEARINGS:
Ball
FUEL TANK CAPACITY:
500 ml
FUEL OIL RATIO:
40:1
RECOMMENDED FUEL OCTANE:
Regular
CHAIN PITCH:
.325 in
SHORTEST GUIDE BAR SUPPLIED:
33cm (13 in.)
LONGEST GUIDE BAR SUPPLIED:
35 cm (15 in.)

 

[HiOctane]

Check the inside of small con rod if there is pitted areas.Sometimes,the bearing breaks due to this condition.The ring could be stuck by light siezure,if the saw has been a long time stopped,stored in humid place.Could be also something that got beteween piston and cylinder and by the fact squeezing the ring groove .

 

[samarsenault]

Yes thank you for your helpful responce. the bore which the bearing goes in is beautiful and smooth - not a scratch on it!

The ring appears to have been stuck when some object came up from the bottom of the piston and did a little gouge into the piston, causing a burr to be pushed up into the ring groove. I'm guessing this object was a piece of bearing.

The saw had sat idle for about 5 years and then ran beautifully for over an hour before it died.

 

[carvinmark]

I would hone the cylinder so the ring can seat. Sounds like the wrist pin bearing was the demon. Good luck.
Mark

 

[rupedoggy]

About half the guys on here will advise to hone the cylinder. It seems to be a good idea because we are used to honing them for automobile and other four stroke engines. Don't hone a two stroke! The piston is as responsible for compression as the ring. It has to be a good tight fit to run properly. The cylinder wall is chrome or nikisil, depending on the model. When it is applied it is smooth and ready for a ring. There is no seating in period, for the two stroke, as we know it for the four stroke. Yes, there is a little time for a slight matching but that is only about one full days work. The manufactures do not want their mechanics to hone cylinders. I know I will catch a little argument over this but I have built over 200 chain saw engines and have never honed one. Mike

 

[carvinmark]

About half the guys on here will advise to hone the cylinder. It seems to be a good idea because we are used to honing them for automobile and other four stroke engines. Don't hone a two stroke! The piston is as responsible for compression as the ring. It has to be a good tight fit to run properly. The cylinder wall is chrome or nikisil, depending on the model. When it is applied it is smooth and ready for a ring. There is no seating in period, for the two stroke, as we know it for the four stroke. Yes, there is a little time for a slight matching but that is only about one full days work. The manufactures do not want their mechanics to hone cylinders. I know I will catch a little argument over this but I have built over 200 chain saw engines and have never honed one. Mike

Hi Mike,
No argument here, I've only done three saws. My experience is in automotive and dirt bikes (2-stroke). I have always honed all of mine, very lightly on the 2-strokes for fear of loosing the nikisil coating. One of the things I look for is a lack of cross hatching to indicate wear. I just never thought it would work properly without honing. You have done alot more saws than me so you must be correct.

Mark

 

[Ekka]

I'm with the dont hone a two stroke crew as well. :biggrinbounce2: