Andrew Wellman
ArboristSite Operative
I know the lower con rod is pressed together but can it be pressed apart? I watch moto repair videos and they rebuild cranks. Can this be done on a saw? I have a press and tooling.
Has anyonen pressed appart lower con rod bearing and rebuilt
- Thread starter Andrew Wellman
- Start date
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buck futter
ArboristSite Guru
they can and sometimes they do for huskys I think, it is harder or you cant on stihls for some reason.
unless you are going to stroke it or something it doesn't make sense economics wise anyway.
unless you are going to stroke it or something it doesn't make sense economics wise anyway.
trappermike
ArboristSite Guru
Other engines(bikes,snowmobiles) have rebuild kits to replace the rod,bearing,and crankpin,but saws don't,so no replacement parts.On many Stihls the big-end crankpin is built into one half of the crank,so no replaceable pin. I pressed a couple apart,very difficult unless you fabricate some proper holding fixture. I did get the Jonsered factory to send me 3 rod kits once,because I talked to the rep from Sweden,but they don't sell them. Only reason to press a crank apart maybe to use a good rod assy. from one crank onto another or whatever...
WHSH
ArboristSite.com Sponsor
The other day I had a 268xp crank that was bad. Litterly the bearings were flat on one side. Just for i put the crank under my harbor freight 12 ton press and to see what i could do. I set it up and started cranking. I did not budge and I was getting nervous about it poping spitting rod out and putting it threw my face or body or blowing up the press. I then applied some heat the an oxy acet set up and gave it some more tension. With a couple of huge resonating "Bangs" the rod pin would push threw in small incriments. I was startling when it would go but finally cam out. The pin and rod looked pretty good, but he bearing was really beat up. I suppose that I could find a bearing that would meet the spec, press it together and see what happened, just as an experiement. Do motorcycle cranks come apart this hard?
trappermike
ArboristSite Guru
I don't think you will find a new bearing at a bearing supply shop or anywhere like that,they are specially made for 2-stroke con rod use,the pin may appear ok visually but I bet it's not due to what that failed bearing put it through at 10G...
Maybe a motorcycle has a rod kit bearing that's the same-a long shot. Better chance to find another saw crank with the flywheel threads buggered(Or something like that) for the parts you need.
If you find parts and get it together my hat's off to you,
then you'll have to true it to within about .001".
Maybe a motorcycle has a rod kit bearing that's the same-a long shot. Better chance to find another saw crank with the flywheel threads buggered(Or something like that) for the parts you need.
If you find parts and get it together my hat's off to you,
then you'll have to true it to within about .001".
WHSH
ArboristSite.com Sponsor
tall order I know but I would love to give it a try.
and you will have to have both halves,,indexed perfectly to each other....or the two crank horizontal centerlines wont be directly in line,,,
WHSH
ArboristSite.com Sponsor
Nothing done yet with the crank. I had to finish the saw and get it back the the customer and I was learning to spray catylized eurethane on my yz125 frame. Fun distractions. I also saw I needed to get a bearing separator to hold the crank in the press and not crush the bearing.
Randy has a thread on this.
"Any idea what this is???"
