Chainsaw knocking sound

[Vintage Engine Repairs]

056 AV super. The knocking I’m referring to is most noticeable at idle - you can’t miss it. Considering digging into the top end to measure and check the piston skirt for wear and check conrod bearings, but before I do I’d like a second opinion. Seems that it’s not audible at WOT, which is the only reason that’s stopping me from thinking it’s actually not an internal issue.

Maybe it’s just not audible over the sound of the running saw.

Thoughts?

 

[frank_]

big-end maybe ?

 

[ericm979]

Clanging sound at idle is usually bad big end bearings.

Check the crank for play.

 

[The Shooters Apprentice]

I’d be checking that crank for play myself, as well as the connecting rod.

 

[frank_]

is that the "blued" crank tom ? from the thread that disappeared

 

[Bob Hedgecutter]

Keep filling the tank and making cuts in that lone log- the saw will tell you if it is internal or not.

 

[Vintage Engine Repairs]

One possible but unlikely cause could have been the plate (8) that sits between part 6 & 9 vibrating or pinging from the exhaust gasses thumping out.

The flanged face of part 8 was rusted / embrittled and wouldn’t sit tightly.

After this video I peened part 8 in between 6 & 9 and added 3 solid rivets. I haven’t actually tested it out since making that repair come to think about it... I’ll start it up tomorrow and see. I think it’s highly unlikely it’s the cause, but you never know I guess..

 

[Mad Professor]

Stethoscope might help you locate the area of the sound.

I've used those on cars/tractors....

 

[cuinrearview]

Nobody believes that you're not going to tear this saw down Tom.

 

[Huskybill]

Stethoscope might help you locate the area of the sound.

I've used those on cars/tractors....

I use a long 3/8” ratchet extension to find noises too.

 

[tomalophicon]

Loose chain adjusting mechanism? Chain looks too loose to me.

 

[GeorgiaVol]

I have had a worn sprocket bearing give off a pinging noise at idle.

 

[Canyon Angler]

I use a long 3/8” ratchet extension to find noises too.

Big long screwdriver works, too. Just jam the handle in yer ear

 

[Vintage Engine Repairs]

Pressure on the clutch drum reduces the clank



However it’s not the clutch assembly..


fairly sure it’s internal…

 

[Bob Hedgecutter]

Big long screwdriver works, too. Just jam the handle in yer ear

In some cases it would work better if the big long screwdriver was inverted.

 

[Vintage Engine Repairs]

 

[GeorgiaVol]

Sometimes I use Scotch to take the edge off too.

 

[Mad Professor]

0.19-0.3 mm piston clearance is ~ 0.008-0.012". That's a lot. New should be ~ 0.08 mm/0.003"

 

[Vintage Engine Repairs]

0.19-0.3 mm piston clearance is ~ 0.008-0.012". That's a lot. New should be ~ 0.08 mm/0.003"

Yep, I agree with you mate, as I said in the video it’s not ideal and it would be nice to put a new piston in - If I relied upon it for firewood I’d replace the piston as mentioned, but for the very occasional bucking of wood here and there that this saw will see, it should be fine. I’m fairly certain that’s not my issue either.

I do think though that the skirt wear is causing spit back and wetting my air filter. No real problem though. I paid $30 USD for the saw so it really owes me nothing.

 

[GeorgiaVol]

Loose baffle in the muffler?