394XP Main Bearing Case Wear?

[TravfromNZ]

Hi everyone. I am currently in the process of rebuilding a 394xp that had a small amount of play in the PTO side bearing. After stripping down and having a look at the cases, I can see that there is some slight deformation in the front half of the case bearing housing. I have tried to show it in the photos - first photo is looking toward the front (bar oil tank) of the saw and the second photo is looking backward toward the rear handle. You can see the indentation quite clearly in the first photo and can see where it starts to happen in the second photo. Its kind of like the constant forward pull on the PTO has 'compressed' the magnesium in the front half of the bearing housing. The bearings are still definitely a pressfit and needed to be heated to get them out - I don't think they would spin inside the case at all. What are your thoughts on this case? Just press new ones in and see if the crank assembly spins freely?

 

[John Stryker]

I think I see what you're talking about. It looks like a little lip around the bearing pocket, or just discolouration from that part being exposed. To me it doesn't look like a spun bearing pocket though, and if the new bearing fits tight, I think it should be good.

 

[2stroker]

Hi everyone. I am currently in the process of rebuilding a 394xp that had a small amount of play in the PTO side bearing. After stripping down and having a look at the cases, I can see that there is some slight deformation in the front half of the case bearing housing. I have tried to show it in the photos - first photo is looking toward the front (bar oil tank) of the saw and the second photo is looking backward toward the rear handle. You can see the indentation quite clearly in the first photo and can see where it starts to happen in the second photo. Its kind of like the constant forward pull on the PTO has 'compressed' the magnesium in the front half of the bearing housing. The bearings are still definitely a pressfit and needed to be heated to get them out - I don't think they would spin inside the case at all. What are your thoughts on this case? Just press new ones in and see if the crank assembly spins freely?View attachment 980358View attachment 980359

It doesn't look like the bearing spun in the case. I would reassemble with locktite applied to the outer race before you drop it into the heated case.
My 2cents,
2stroker

 

[TravfromNZ]

Yea - I had a similar thought. Which Loctite in particular - the high temp one I saw went up to 230 degrees Celsius but that probably isn't high enough? Cheers.

 

[2stroker]

I can't believe the sump would get near 240C(450F) so that should work perfectly. Just make sure both surfaces are squeaky clean!
2stroker

 

[TravfromNZ]

I can't believe the sump would get near 240C(450F) so that should work perfectly. Just make sure both surfaces are squeaky clean!
2stroker

Thanks for the suggestions. Unfortunately I had another look at it with fresh eyes this morning and discovered that there is way to much slop and the bearing wiggles around freely once put into the case. Anyone know of any good secondhand cases haha?

 

[mbrick]

So much that loctite 609 or 648 won't take it up?

Maybe the chain was ran with too much tension? Speaks to the bearing and crank durability I suppose...

 

[TravfromNZ]

So much that loctite 609 or 648 won't take it up?

Maybe the chain was ran with too much tension? Speaks to the bearing and crank durability I suppose...

Yea, I wouldn't be confident that retaining compound would take up that gap, I'll put the bearing back in and upload a video. I am surprised that it did not put more wear on the big end bearings - there doesn't seem to be any radial play in the conrod. Very strange.

 

[mbrick]

Dang. If you don't think it would hold up then it's time to find cases.

 

[TravfromNZ]

Dang. If you don't think it would hold up then it's time to find cases.

Yep no good. Here's a couple of shorts of the problem.

 

[mbrick]

That is pretty wallowed out!

 

[Bob Hedgecutter]

You are sure you have the correct bearings eh?
Going to be an interesting prospect finding a good set of 394 cases here in little old NZ.
Wonder what the odds are of that saw having been used hard on a portable mill.

 

[ChillyB]

There for sure is a loctite compound that would fix that. Might be the last hurrah for those cases, but you are about to get new cases anyhow.

Is 640 the stuff designed for taking up fit for loose sleeves and bearing races?

 

[TravfromNZ]

You are sure you have the correct bearings eh?
Going to be an interesting prospect finding a good set of 394 cases here in little old NZ.
Wonder what the odds are of that saw having been used hard on a portable mill.

Yea mate haha - that was the bearing that came out of the case. You wouldn't believe it but after stressing about having to tell my wife it was going to cost $450 for new cases, I have managed to find an old 394 chassis from a local husky shop - I had given up all hope but luckily there is a god after all. What is very surprising is that the crank and cylinder are mint. I had wondered if that frontward pull would have played havoc with the big end bearing but it seems to be ok.

 

[Bob Hedgecutter]

Yea mate haha - that was the bearing that came out of the case. You wouldn't believe it but after stressing about having to tell my wife it was going to cost $450 for new cases, I have managed to find an old 394 chassis from a local husky shop - I had given up all hope but luckily there is a god after all. What is very surprising is that the crank and cylinder are mint. I had wondered if that frontward pull would have played havoc with the big end bearing but it seems to be ok.

Hopefully no issues with the "new" cases then.
Was a heck of a stroke of luck. 395 parts are a bit easier here, but they did not make the 394 for long enough for lots of them to have been here.
Could be worse- it could have been a Jonsered 2094!

 

[TravfromNZ]

Hopefully no issues with the "new" cases then.
Was a heck of a stroke of luck. 395 parts are a bit easier here, but they did not make the 394 for long enough for lots of them to have been here.
Could be worse- it could have been a Jonsered 2094!

Haha funny you say that. I had been looking at buying a Jred 2095 recently but parts availability is pretty scary.

 

[Bob Hedgecutter]

Haha funny you say that. I had been looking at buying a Jred 2095 recently but parts availability is pretty scary.

2094 was the one to have and just that tad stronger than the 2095.
I have one very good 2094 and another waiting to come down to me from Northland as backup and spares- so I have no need to go Orange.

 

[TravfromNZ]

2094 was the one to have and just that tad stronger than the 2095.
I have one very good 2094 and another waiting to come down to me from Northland as backup and spares- so I have no need to go Orange.

Fair enough mate. The Jared's are definitely formidable saws and I wouldn't mind one someday.

My recent experience with the 394 has definitely given me insight to the good ole saying "play up like a secondhand chainsaw". Problem is that case wear is near impossible to pickup until it is split.

 

[TravfromNZ]

Fixed one thing with a new case but the new case also has a small issue. Missing a small section of the crank sealing surface. Is this a JB weld/RTV type fix?

 

[Bob Hedgecutter]

There is a reason that 394 ended up in the "too hard basket" at the dealers eh? That missing bit might be it.
Did you happen to ask if anyone there remembered why the saw in question was retired? If it was burned out because of an unexplained air leak........