371\2171 rebuild

[Chris_In_VT]

Gonna be a long post, sorry guys...
tl;dr version- I put new bearings in a 372 series saw and now the crank is hard to turn. Yes I relieved the tension on the crank during install.


Alright, so I had a bunch of parts laying around, including a 371xp with the tank mount broken off the clutch side case, and a 2171 with the flywheel side smashed up. What to do about that?

Make a Husqared! Or Jonskavarna? I like Husqared better....
371xp flywheel case half, 2171 clutch side case.

Anyways, this is my first attempt at a full rebuild (case split, new bearings, etc.) I've done plenty of top end rebuilds, carb kits, muffler mods, etc. but this is my first venture into crank bearings.

I got the cases split just fine. Heat gun and rubber mallet on the crank. Don't have a proper splitter tool.
Bearings out, cases cleaned up.
Did some research on here, decided to install the bearings in the case first as opposed to crank first, and ended up heating the case halves in the oven. The bearings dropped right in, easy as pie.

Now, crank into the case\bearings. I used the case bolts to pull the halves together. Worked just fine.
Things are going much better than I expected for my first shot at this.
Case halves together, bolts snugged down, and the crank is hard to turn.
YES I hit both ends of the crank as I was pulling the halves together to relieve tension (rubber mallet)
I loosened the case bolts, and the crank turned smooth and easy. Tighten them up, hard to turn. Tried giving it a few more whacks, didn't help.
Hmm...

Pulled a smart move (NOT!) and went ahead to install the crank seals. After I put the pto side seal in, the crank is even harder to turn.

Any ideas what went wrong? Maybe because of the different model case halves? (I thought it would be fine, same chance as another used case half working right)

I'm guessing I'll need to split the case again, and might need new seals as well...

Take it easy on me, this is my first bottom end rebuild!

[photo="medium"]2265[/photo]

 

[mdavlee]

Check to see if one bearings is seated too deep.

 

[tlandrum]

you need a brass hammer to hit both ends of the crank to center it up and relieve side tension on the bearings. it will loosen up after you get it hit hard enough

 

[Chris_In_VT]

Check to see if one bearings is seated too deep.

What is too deep?
I don't remember where they were when I split the cases.

I know on the pto side the bearing was flush with the inside of the case, wouldn't go any deeper. The flywheel side was well below the inside of the crankcase.

 

[Chris_In_VT]

you need a brass hammer to hit both ends of the crank to center it up and relieve side tension on the bearings. it will loosen up after you get it hit hard enough

I hit it pretty darn hard with the rubber mallet.
Maybe the rubber absorbed too much of the blow?
Not sure I have a brass hammer, but will a piece of wood over the end of the crank and a BFH be safe?

 

[mdavlee]

I hit it pretty darn hard with the rubber mallet.
Maybe the rubber absorbed too much of the blow?
Not sure I have a brass hammer, but will a piece of wood over the end of the crank and a BFH be safe?

Maybe find a brass drift pin. That's what I use instead of hard metal on it.

 

[Chris_In_VT]

Ok, I do have one of those.
Will give that a shot.

 

[blsnelling]

The inner race is still not far enough onto the crank. I've dealt with this a couple times on the same model. I resorted to putting a punch against the inner race. Risky, but it worked. Don't let it slip off that race!

 

[angelo c]

Ok. I can't figure out what handle/ tank combo is gonna work on that Frankenstein saw . The Husky and Jonny handles don't swap unless the tank goes with it. AFAICR.

 

[Chris_In_VT]

Tried the brass punch, it helped, but it still doesn't turn "silky smooth" like I think it should. Still some resistance.

Brad, which inner race? On the clutch side? Or the flywheel side?
Have to pull the seals for that.
Knew I shouldn't have put them in yet...

 

[Chris_In_VT]

Ok. I can't figure out what handle/ tank combo is gonna work on that Frankenstein saw . The Husky and Jonny handles don't swap unless the tank goes with it. AFAICR.

It will have a 2071 tank, and I'm gonna TRY and use a 372 handle. It LOOKS like I just need to drill a new hole in the handlebar below where the spring mount on the cylinder is.
371 jug+slug, 372 top cover and recoil, 2071 clutch cover, 372 brake handle, HD6 carb off 371xp, it's gonna be UG-LEE!

A ways to go yet though, need this bearing issue figured out.
After that it will be smooth sailing, I know I can get the rest together just fine.

 

[old-cat]

The crank will NOT turn silky smooth with seals on, only with them off.

 

[Chris_In_VT]

The crank will NOT turn silky smooth with seals on, only with them off.

Huh, well maybe it's fine then. Before I gave it some real good whacks, it was hard to turn by hand. Now it almost feels like turning it with the piston+cylinder on, sparkplug out (very little compression)

Like I said, this is my first bottom end rebuild. I didn't know that

I figured this was a good saw to practice my first total rebuild on. If it blows up, oh well, I'm not out a high value saw. If it works good, then now I have the confidence to do this rebuild. It's not like I will ever sell it either. Who the heck would buy the thing?

 

[old-cat]

I much prefer having the seals off to make sure the crank is rotating properly. BUT, these stinking little Husky 350 things, that's an impossibility. One I put together was REALLY hard to turn but it ran just fine!