Basic Rebuild: 034 rebuild and mods

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Great job Eddie. It's so well presented even I can understand it. I can't wait for the carburetor presentation. Thanks for taking the time to share your skils with us.
 
Thanks for all the compliments, guys. I really appreciate it.
I am using a new Nikon Coolpix and I noticed that a few of the pics are a little blurry. Since the display is so small I can't always tell till I post them. I am getting better at using it though, since I finally read the dumb manual on how to use the macro feature...

Publish a book, eh... I wonder how one would go about doing that?

Belgian, on the 034 the impulse hose comes up and attaches to a nipple on the tank housing and comes through a little hole in the manifold to get to the carb.
When I put the aluminum flange adapter on it blocks off the hole, so when I put pressure in the crankcase I am checking the hose all the way up to the flange adapter, as well as the manifold, seals, gaskets, etc.
Before I had the adaper, I just took an old carb, stripped it to the bare body, even taking out the throttle shaft and choke shaft. I used epoxy to seal off every opening into the venturi, and threaded a pipe thread nipple fitting into the choke side to make a flange adapter that would fit in place of the carb. I used it for years and still have it. The nice thing is that nearly all of these have the same bolt pattern regardless of whether it is a ZAMA or Walbro.
 
It Runs!!!

Got everything done, tuned it to 13400, runs great, idles smooth, and pulls chips like crazy!!!

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This thread is permanently bookmarked by me now. It looks like I'm about to start my first project saw and it appears that splitting the case is going to be mandatory. The crankshaft on the flywheel side wobbles like crazy!

Only bad thing, is I don't know if I want to try and find the right tools to split the case or just strip it down and have the Stihl mechanic replace the bearings and/or crank for me. Yikes! I would love to tackle splitting/reassembling it myself but I bet the tools are either hard to find or insanely expensive! hahah

Thanks for the thread. It's awesome. Only weakness in it is that I think it makes things look 'too easy'. hahaha

Thanks again,
 
Thanks, Matt
Take a trip to Virginia Beach and bring your parts and I will help you do it. I didn't mean to make it look easier than it is, but the truth is that with the right tools and a little practice it really is not too hard a job. I could have got it done a whole lot faster if I wasn't taking pics along the way!!!

You should be able to find a dealer that would be willing to assist for a nominal fee if you have pretty much stripped and ready, and give him some parts business. It may take some driving around but it might be worth it.
 
This is why I check this site every day. Lots and lots of very good information.
I have an 031 That I need to rebuild. Also an 051 and 056 that need some work, but not a complete rebuild. I have an 012 that runs good.
Also I bought out a Sthil shop that has been closed since 1985 and got several service manual in the deal, but I will save this thread for future reference.
I looked at several of the tools you used and since I am a mechanist I hope that I can make some of them.
Very instructive and informative. AAAAA+++++++++. You may go to the heaad of the class. Tom
 
Thank-you Sthil #1 for a very informative thread and for the detailed pictures of a saw rebuild. I found this thread to be very helpful to see how a pro goes about splitting the case using the right tools.

This seems like a good thread to ask this question without starting a new thread.

I have a question that you or another knowlegeble person might be able to answer concerning crankshafts.

The main question I have is it possible for a crank to worn out and should not be reused if the saw is to be totally rebuilt.

If it is possible for a crank to be non useable for service. If so , how does one go about checking it ???

What is prompting this question is that we see many examples of worn bearing and seals on the bottom end. What is causing this to happen??? Possibly an out of round condition where the bearings ride on the crank?? A worn bearing on the connecting rod???

I can't help but think that the crank might be a possible culprit in a case of worn bearings where the crank is spinning around at 12-13 thou rpm. Over time a not so perfect crank is beating the bearings into a condition that they can no longer function and allow the seals to open up and create a lean running condition.

The crank is the heart and soul of the two stroke engine. Is it designed to be the hardest non wearing part in the engine provided it gets the proper lubrication. If this is the case would all the other parts connected to the crank be considered wear items that need replacing from time to time.

I know this is a overkill type question but the more I get into this saw repair and rebuilding I can't help but think the bottom end of the saw is more the problem with some running conditions than are carb, pulse lines and even piston and cylinder, crank seals and what not.

Larry
 
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I think I understand what you are asking, and as is usually the case here at AS, there will be those that agree and don't. My experience is that if the con rod will not lean over far enough to touch the counterweight when the rod is at BDC, and there is no up and down end play while holding the crank steady, then it is probably usable. I always push the rod to the side and roll the cage around with a pick to see if there are any cracks, and then check the other side as well. I have used cranks that had a blue little end, from lean or overheat (You remember from class, right Larry?!) and as long as the bearing and pin feel good I have not had any trouble.
I suspect that what knocks out crank bearings is cutting with improperly sharpened chains. Either the rakers are all over the place, or the cutters are uneven, or both. That will hammer out a clutch bearing.
I am fairly certain that the crank in that 034 had at least 500 hours of run time on it, and it was fine. The bearings were OK too, in spite of a trashed chain that was on the saw when I got it. I pulled the bearings off since the new case already had new ones installed, and also so I could illustrate the procedure for replacing them.
You have seen the crank assembly process at STIHL. No out of balance cranks leave there.
Hope that answers your question.
BTW, have you by chance found me a clutch for the 07 yet? I hope!!!
 
Great thread

Good job Eddie. Step by step with pics, thats as good as it gets. That saw looks much better than it did when I saw it sitting on your bench a few weeks ago.

Those tools do indeed make splitting the case a breeze for sure. Every shop should have those tools along with all the saw buffs that are really into saws.

Of note and just a idea, this thread could and should be used in a shop class up on a big screen, hint hint.
 
Thanks Sthil #1 , yes, you did answer my question. The main reason I asked about the crank is because some of the saws that I have split came apart way too easy and the bearings didn't require much if any effort to remove them the crank. Some of those bearings stayed in the case halves which made me suspect the crank could be worn in some way. Hope this makes sense.

BTW, I think you have me mixed up with someone else. I haven't had any formal training concerning engines although I wished I did have some or be able to take some classes in engine repair. It would sure be helpful in my line of work. I am just another DIYer that is into chainsaw maintenance and repair mostly to keep my little fleet of work saws going because I am a pro arborist and need them to make a living. I can't help you out with the 07 clutch either. Sorry

Larry
 
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Thanks Tom, I am thinking about it.
Maybe for the book I will publish, someday...

Ax-man, I am sorry I mixed you up with another Larry I know.
I think I mentioned it in the thread, but a bearing should have a tight fit on the race that spins, and it can have a looser fit on the race that is fixed. If the bearing slides off the crank easy or with little effort I would say the tolerance was out of spec. This is not a great way to fix it but it would get you by for your own use, by taking a center punch and very carefully and evenly going around the circumference of the bearing seat area on the crankshaft, raising little dimples. Space them evenly and in a couple of rows, then when the bearing is mounted it will be tight. Some Locktite bearing mount adhesive might also be an option.
 
That info is priceless, thank-you Sthil #1 it answers my question even more. That is exactly the answer I was after.

Larry
 
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