Another Husqvarna 350 to salvage

mike_belben · May 31, 2021, 10:30:14 PM

Good idea.

You can also put a little crimp across the thread tops by wacking the bolts with a sharp chisel lengthwise. Not too much, you dont want the steel to eat the aluminum threads. Just enough for the screws to bind up a bit and kinda make it a higher thread fit class.

loctite them too.

Old Greenhorn · June 13, 2021, 01:53:33 PM

Well just an update. The parts came and I finally had time Friday to start putting it back together. I mentioned how that went in the 'did something dumb' thread. So I went out to visit Spike60 he he hooked me up with a replacement ring. When I got back to it on Saturday I put it back together I only had one screw left over. :D :D
But it still doesn't have the compression it should. It has spark and is getting gas. I am not really a 2 cycle guy and I don't really understand how these things cycle through a stroke. My understanding is that the entire crankcase is pressurized, but I don't understand why. If that is the case, it may be leaking out the bottom around the crank seals. Is that possible? Well the goal here was to learn something and I guess I will learn some more. I'll let it sit for a little more, then tear it apart again.
Any suggestions?

mike_belben · June 13, 2021, 02:27:53 PM

When the piston rises it is compression above and suction below. Just flip it upside down mentally, the piston rising toward the plug is a compression stroke above the piston and a simultaneous intake stroke below the piston. Its sucking charge in. The intake manifold aims into the crankcase BELOW the piston skirt. The piston skirt length top and bottom makes up the valve timing.

Plug fires, bang, piston descends from the plug, reveals the exhaust port then the tops of the transfer ports and now the bottom of the piston plunges down into the crankcase, forcing mixture from below the piston, up and around to the top. Thats why pro saws have windows in the sides of the skirt. The piston sorta has two tops.

Its a 4 stroke with siamesed steps doing 2 simultaneous processes.. Hence a 2stroke. Thats why they go bump bump. Bump bump. Bump bump like a harley. Well.. A harley does it because of V rods and the jug geometry. A saw does it because there are two different compressions. One below, then one above.

When you cut the jug, your second bump gets harder. When you epoxy the extra space in the block, your first one does too.

Crank seals are subject to positive and negative pulsations. Once up to speed a column of inertia will probably switch the aggregate atmosphere in the base to pretty much all pressurized. Either there air ramming in or piston coming down. No time for vacuum. Thats my guess.

Spike60 · June 14, 2021, 05:46:28 AM

An air leak from something like the crank seals would cause running issues, but it's not enough of a leak where you'd be able to feel a lack of compression like you do when pulling over a saw without a spark plug in it.

In my experience, the majority of aftermarket kits are low on compression out of the box. They don't have enough "squish" from the factory. Sometimes a gasket delete will raise it up enough to be useable.

Old Greenhorn · June 14, 2021, 08:12:51 AM

Thanks Bob, I will give that a try first. I did note that the new gasket seems I tad thicker than the OEM, but never thought to measure it. I am thinking there may be another leak some where and I may not have found the original problem that you had diagnosed whenever you looked at this one. The owner said "something about the lower end" but he couldn't remember the details. This is just an educational project for me as I obviously don't know enough about them and could always use a little more schooling. I'll keep poking along, remove the gasket and re-check my other work and try again. I also have that one leftover screw which is short (1/2") and about the size of a #12 that I can't find a home for so I need to figure that out also. The shop manual could be better for this saw. ;D

mike_belben · June 14, 2021, 11:17:15 AM

the "easiest" if not only way to find a leak, is to build a rig to pressure and vacuum test the saw. you need a blockoff for the exhaust and the intake with carb removed. then a compression tester adapter to thread into the plug hole. and a way to draw and meaasure vacuum as well as positive pressure to see that both hold. you can submerge with pressure to find the leak obviously. it is a chore. i havent found my rig or blockoff plates from the move and have just said nah to starting over.

innertube rubber scrap makes good gaskets to seal the metal blankoff plates

HemlockKing · June 14, 2021, 12:58:23 PM

Quote from: mike_belben on May 29, 2021, 08:48:41 PM
Ive had a few engineer friends that have been sent for the US company to china to oversee manufacturing issues. And ive heard that from them too.. China CAN make good parts if you stay ontop of them and are willing to pay.
Ive also heard from them and others about a lot of spec for no chinese derived steels in a part batch. I guess they are or were notorious for low electric furnace temps leading to non-homogenous alloying. Deviation from batch to batch or hardness deviation from end to end, part to part etc.

Case by case basis i guess. I hate that we are all going poor at home and having to send them our money for their substandard junk because its half price of the real deal that costs 5x more USD than it used to. Or the other side of the coin.. That the pittsburg ratchet is better than the craftsman, for less.

Sure the products are cheaper... but all the jobs are going over seas, not exactly great for your own economy stimulation except for big corps who sell out the work to some Chinese/North Korean children in a sweat shop. I've been trying to avoid made in China for the last 5 years or so. It's hard but I'm willing to pay for quality, not only that but I see China as a threat to our way of life over here. They are trying to expand influence, my government is infiltrated by Chinese money, they sell out their own people and land so China can exploit us and profit. The fisheries come to mind too, in the last 10 years they have all been bought up by Chinese wealthy.

Old Greenhorn · November 06, 2022, 07:52:35 PM

Reviving this thread. I can't believe I've had that saw sitting on the bench for well over a year now. Today was rainy and I was looking for a distraction so I opened it up again. I replaced the head gasket I had removed, confirmed I had gas flow through the carb and I have spark. Put it all back together ...again.. and still only got one single pop, which may have been wishful thinking, but it got me excited anyway. The compression still seems lower than it should be. It won't pop on ether either. I am thinking there has to be a leak in the crank seals but I have never had one of these in half, not sure I can pull that off. I did check the boot clamp again and it is tight. I do have the steel clamp to put on when I figure the rest of it out. I assume I just cut the plastic one off? But that's later, I can see the original is tight and takes effort to snap shut. There has to be a leak here I don't yet understand.
Anybody have any ideas? Think I can replace the crank seals?

Spike60 · November 07, 2022, 06:39:19 AM

Tom; I think that top end is junk, and it's never gonna run. Could feel it when I did the slow pull when you brought it up. The compression that we'd like to feel, (or measure, but there was no point in pulling out the gage for that thing), occurs when the piston is at the top of it's run. At that point it's above all the ports, the seals really have nothing to do with the problem. The only leaks possible at that stage are a loose spark plug, or leaking/loose deco.

Old Greenhorn · November 07, 2022, 06:43:53 AM

Well, it's possible I have the wrong ring in there. I messed up the first one I got with the P&H kit and got another one from you, but maybe it's not the right size. It goes in awfully easy.

Spike60 · November 07, 2022, 07:19:52 AM

There were 2 rings for the OEM 350 kits. Original was the 44mm, the later was 45mm. The later kit is easily identified by having the capped transfer covers. Whether or not this holds true for the various cheap kits that are out there is anyone's guess. But both styles have been aped in one way or another.

Old Greenhorn · November 07, 2022, 08:04:27 AM

Well, I'd hate to think I spent 100 bucks for junk. >:(
Not sure what you mean by transfer covers. Although I don't have the knowledge to diagnose this properly, I find it hard to believe that it can't be fixed.

Spike60 · November 07, 2022, 07:46:15 PM

44mm ring in a 45mm piston might cause the problem if that's what we did. (or they supplied the wrong piston in the box) How did we decide which ring to use? Did we measure anything? (you're the machinist lol )

Old Greenhorn · November 07, 2022, 07:56:04 PM

I think I feel a sharp poke in my ribs right now. OK, OK, I will pull it apart again and measure everything. I could have reached 2' top my right and grabbed the calipers yesterday when it was open, but no, that never occurred to me. ;D

Spike60 · November 12, 2022, 07:10:33 PM

What's going on with this project?

I've got a 350 take off top end that I know runs, and you are welcome to it. Why not drop that on your saw and see if she fires up?

Old Greenhorn · November 12, 2022, 08:26:45 PM

Well, that's an offer I can't refuse! Truth is, I just haven't gotten back to it. I have been trying to work on paying work and I know I needed to take it apart again to measure what I actually have in there. I am suspicious I have the wrong (smaller) ring in it.
If I can get some time tomorrow, I can rip it apart again and measure things up, then hopefully swing down on Monday. Never look a gift horse in the mouth.
BTW, what are you guys carrying for 2 cycle oil these days that is not in those tiny bottles? I am out and I'd rather buy from you than 'them', but I hate the little bottles. I like those pint (or whatever) bottles you can measure out with. I don't think I have seen those in your shop though.

By the way, has Bill brought in his new climbing saw for you to check over?

Spike60 · November 13, 2022, 06:51:11 AM

"Make an offer", huh? I'll haul it away for $50.

No mix other than in the litttle bottles. In fact, practically no oil left at all, as everyone has been grabbing extra with our impending retirement. Going to order some mix and bar oil from Kawi tomorrow, since we still have a month to go. Their minimum is only 15 cases, and we get it in 2 days. Husky's minmum is 50 and it takes over a month to ship from their oil supplier.

Old Greenhorn · November 14, 2022, 09:19:20 PM

OK, time to put this one to bed, I hope. Today in the afternoon I ran out to Spike's shop but Bob wasn't there, he was making a delivery in another county. His partner Warren looked like he's been run hard and put up wet jus trying to get things done. He didn't have time to chat, just too busy. But Bob had marked that P&C with my name so I picked it up and bought a couple of things off the 'get rid of it' table.
I came home and pulled the head apart again and this time, I measured everything. Of course, this showed me what I did wrong. If you go back in this thread to reply 35 I think, you will see where I messed up the ring I got with the new cylinder. So I went and got another from Bob, he did ask me which size and either I told him 44mm or we both assumed. Turns out it is a 45mm cylinder, so the 44mm piston ring, amazingly, did not make compression. >:( ;D THAT was my problem, which I did entirely to myself.
SO as long as it was all apart, I put in the P&C that I just picked up. I buttoned it all up, put a little fuel in, 3 pulls on choke and it fired. Opened the choke and off it went on the next pull. Runs like a top. 8)
Came in, had dinner, went back out and as I got the saw without a B&C, I looked around and realized I had gotten an X-cut chain for my 18" small mount bar that is a spare for my 450. I had been thinking of putting that bar back on the 450, but it seems a better idea to run that on the 350. So I did a little cleanup work on that bar and mounted it up with the new chain and gave it a little test goose, but it was already pitch dark, so testing is tomorrow.

Assuming all is well and it holds up, and I have no doubt it will, that will give me 3 working saws which makes me happy. I can leave one at the mill if I want and still have two to work with otherwise. So Bob, thank you for that and all the help. I'll be back out to grab the right ring for the AM P&C and settle up on the stuff I got today. I'll take the brand new unused P&C and stick it on the shelf in case I need it some day. Pretty confident it will work with the right ring in it. ;D Last stupid question: Those 350's were all .325 pitch setups, right? I didn't pull the clutch sprocket to check it.

Spike60 · November 15, 2022, 06:20:04 AM

Sorry I missed ya Tom. Was delivering a tractor on some mountain up in Roxbury. When I got there the straps that were wet from Sat rain were starting to freeze up. After I unloaded it and monkeyed around hooking up the customer's battery tender, I was starting to freeze up. Only had a light jacket on. Love the feeling of all that heat coming out of the dash when I hopped back in the truck.

Glad the saw is up and running. Should have 45mm rings in stock, but will double check. They did all come with .325 chain. Some .325 haters insist on switching them to 3/8 but technically, there is no oil gear to properly switch to a rim sprocket set up. 346 drum can be used, but it's a bit of a sloppy fit. I did it myself on a Jonny 2150 with a 346 P&C several years ago, and there's been no problem. But I didn't do it to run 3/8, I installed an 8 pin .325 rim which I think is the best way to go with these builds. That saw is surprisingly quick. We ought to compare them while I still have some 346 kits in stock. lol

Warren and I are both kind of frazzled. Trying to wind this down but folks just keep coming in. We have clamped down on the "before you close" equipment that isn't even broken. The non-stop parade of Exmarks has kept us from doing the snow blowers that we have commited to, (of which there will be no more), and tonights unusually early 3-5" snow forecast will provide for a very entertaining day. 39 days to go.

Old Greenhorn · November 15, 2022, 12:55:18 PM

Well I gave it a test this morning while waiting for the shop to warm up a bit. It idles perfect and starts easy with a quick throttle response. But I test it on a 19" log of dried hard ash and it was dogging down when loaded. I am pith poor at tuning, never got the hang, but I tweaked the high idle just a tiny bit (it had been bottomed out), and I mean tiny, and tried it again. Seems to cut great now. It does dog a bit when the bar is fully loaded in solid wood, but that really is something I would consider normal for a 50cc saw with an 18" bar. There is a limit to what it will pull after all.

Funny side note. When I was cleaning up the bench I took a minute to read the data sheet that was included with the new X-Cut chain. I had been given that chain as a gift from one of the Husky guys at Boonville. Maybe it was older stock, who knows? Anyway the data sheet (first time I've seen or gotten one) had a very nice chart on all the Husky chains, the files required for each, the sharpening angles, the file and raker guide part numbers and diagrams. Vey nicely done. I said "all the Husky chains" and it did, that is except for any reference to X-cut chains. No part numbers, no filing info (which is different from all the others) none of it, not one mention! That's a strange thing to put in an X-cut chain box. Anyway, it struck me as odd.

Wlmedley · November 16, 2022, 05:21:59 PM

Tom,I bought a X cut chain for my 372 at the Paul Bunyan show in Ohio after reading that you liked yours.Wished I had bought a couple more.Only $18 a piece.I asked the guy at the booth if they were something new and he said no that was just Husky's brand name.Haven't really looked it over as chain on my saw is still in good shape.Is that what your impression is?

Old Greenhorn · November 16, 2022, 05:37:42 PM

The guy at the booth needs to go to an education camp. He don't know what he is talking about. :D 18 bucks is a great price for that chain though.

These chains are sharpened differently, the file is held at 90°, there is no 10° drop angle. There should be sharpening instructions with the chain, but as noted earlier, they might be wrong. You can google it, but those angles should also be on the box. I find with no top angle all I have to do is follow the witness mark and keep the file level. Much easier, therefore quicker. It's just an opinion but it seems to hold up a bit better against things like dirt, and once I thought I dinged it, in fact I am sure I did, but when I sharpened it that night, I had no wrecked up teeth. ;D
When I out that chain on a 20" bar on my 450 I thought I might be asking to much, but it seems the saw cuts much freer now and it is a lot harder to make it bog down.
So yeah, I am happy. 8)

Wlmedley · November 16, 2022, 05:47:32 PM

If that's the case my little roller guide that sets on chain isn't going to work right. Thanks for the information.Glad you got your saw running.Had me worried for a little while :laugh:

Old Greenhorn · November 16, 2022, 06:25:47 PM

They have a new roller guide for X-cut. Most dealers will have to order it I think, I got one for 3/8 but frankly after a few times sharpening I stopped using it because on the zero top angle. I depended on the roller guide for that drop angle, which my hands always seemed to have trouble with.