Husquvarna 390 xp pto side bearing failures.

[XSKIER]

So Shawn,

What was the runout on that crank? .002" run out at high rpm will blow out any steel or plastic caged bearing a whole lot quicker than oil mix ratio or chain tension.

 

[Dieselshawn]

Xskier: I'll ask tomorrow. Interesting.

 

[duramax99]

that 390 has been retired to the spare parts bin haha. I've seen bearing failures with limited and unlimited coils. Rpm seems to be a factor but not the deciding factor in how long a 390 crank lasts.

 

[Andyshine77]

So Shawn,

What was the runout on that crank? .002" run out at high rpm will blow out any steel or plastic caged bearing a whole lot quicker than oil mix ratio or chain tension.

Cranks can bend. Get a saw pinched in a big tree and boy can that pull hard on a chain.

 

[Andyshine77]

that 390 has been retired to the spare parts bin haha. I've seen bearing failures with limited and unlimited coils. Rpm seems to be a factor but not the deciding factor in how long a 390 crank lasts.

That's not a pretty sight. I've seen some ported 390's spin pretty high rpm's.

 

[Dieselshawn]

Duramax99: agreed with andyshine77, that's not a pretty site at all. :msp_w00t:

Knock on wood that that doesn't happen to my ms260.

 

[bezza1]

one of my 394s or 395 carnt rember what one

 

[gilfish]

Looks like someone fired a bullet into that cylinder and took the top off the piston?

 

[Mastermind]

Stuff breaks sometimes. :msp_sad:

 

[CJ1]

I have ran 372,385 and 390's HARD for many years at 50:1 with no failures and limbed with all of them. Granted I don't run them WOT without a load on them but they never got babied either. Like Randy said "stuff breaks". CJ

 

[Dieselshawn]

CJ1: not WOT for limbing likely contributed to the long life of your saw.

I do the same with my ms260. I find no need to go WOT as the saw slices limbs like hot knife through butter with a properly sharp chain.

 

[tpope]

You run a hotrod hard enough and long enough... you'll find the weak links. If you can't run with the big dogs... stay under the doublewide.

 

[Dieselshawn]

Tpope: You speaking of the 260? Very true, that's why only the 260 is modded. The 2 026 are staying stock for now.

 

[tpope]

Tpope: You speaking of the 260? Very true, that's why only the 260 is modded. The 2 026 are staying stock for now.

Umm NO. Sorry, I have no recent experience with those saws. I am relating my experiences with Chevy V-8s. Seen a few rods through the block and oil left on the pavement. I love RPMs and know that there is no replacement for displacement. Chainsaws included... It took me a long time to adopt fuel injection and computer control. Once I understood them and their capabilities and limitations... Oh JOY!

 

[Dieselshawn]

Tpope: here's a solution for those throwing rod problems:

I've got a 500 hp cummins 5.9l that makes that power at just 1,850 rpms. No rod issues here and no silly electronic fuel injection systems to melt pistons. :cool2:

Also enough torque to pull a tree down at idle.

 

[tpope]

It ain't got no lope at idle... just would not be in character in my '55 car.

 

[Dieselshawn]

Tpope: yes, that would be true. Gotta have the ol' lopey idle.