General Product Question
why do chains keep coming off my 455 rancher..seems like can...
General Product Question posted October 4, 2018 by Ronald Menard
98 Views, 3 Comments
Question:
why do chains keep coming off my 455 rancher..seems like can not even use for light cutting for more than 20 minutes and chains keep coing off and I end up getting new chains (chains are tight before using)
Answer
This is because they lengthen during use form heating. This not just Poulan/Husqvarna problem as all chainsaws do this or at least it been that for the 50 years that I have used chainsaws.
You just need to pay attention and keep them adjusted. Note you should always loose a chain after prone long use before storage or you could break a crankshaft.
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Ronald, as stated by Eugene all chains heat up and lengthen or stretch over time.
But I have found that some individuals also over tighten their chains, which actually causes even more heat due to the friction of the steel chain riding on the steel bar and results in the chain stretching even faster..
I have found that Not tightening your chain as much reduces the amount of heating and stretching. I would recommend when you tension the chain, (And "Do Not Tighten the Chain with the tensioner screw') That screw adjustment is just designed to take the slack out of the chain. The "Bar Nuts" should be Tight this is what actually holds the bar and chain in position. So tension the chain until the Drive links just come up and touch the underside of the bar, some individuals even use a "Penny" as a gauge and bring the drive link up, just until it touches a "penny" thickness between the bar and drive link. Just a very slight gap. Do Not let the drive links hang down so they are protruding out of the bar slot, this is very dangerous. Also Do Not tension a chain on a Bar that is warm or hot. let the bar cool down to ambient temperatures before re-adjusting. The steel bar actually expands quite a bit when it heats up. Finally, the key ingredient that is causing this problem is "Friction" or steel chain riding on steel bar, so to reduce the friction, lubrication is extremely important, constantly check when cutting that your bar is getting chain oil.
I hope the above helps, and you are not alone. Many Individuals have this problem with chain tensioning and bar oiling. Also sorry for being so wordy, but its a good question and topic.
Karla
PS. I am Not a Husqvarna Representative or Repair Service, just an experimental chainsaw person.
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Ronald,
Just one more thought about over tensioning a chain.
An easy tell tale sign that you are getting too much metal to metal wear on your bar, or not enough lubrication, usually one of the two reasons. Is check your bar periodically, remove it from the chainsaw, remove the chain, and lay the bar down flat on its side, use a metal tip tool like a large flat tip screwdriver or even a metal paint scraper, and from the center of the bar to the edge, move the flat tip tool If you feel it hangup as it hits the edge then most likely you have a "Burr" on the edge of the bar. Do this in several spots both top and bottom, and also flip the bar over and do the other side too. (Note: Do Not use your thumb to feel for this burr, because in some cases this "Burr" is like a razor and very sharp). If the "Burr" is severe enough you will be able to see it by just looking at the bar.
Anyhow this wear is do to a lot of Metal to Metal contact, and may be a Tell tale sign that you are over tensioning the bar. An easy fix for the bar is using a Flat file, create a very slight chamfer on the edge of the bar removing the burr. Let the bar extend over the edge of a flat surface or work table, and just a couple of swipes with the file raised up off the side of the bar at like maybe 10 degrees or less, will remove the burr.. "Do Not over file the edge of the bar thinking a 30 degree chamfer will be better. No - just remove the burr on both sides of the bar, and all the way around the edge of the bar, and on both sides.
Then put the bar and chain back on the chainsaw, and lessen the tension just a little bit, making sure to keep the "Bar Nuts" good and tight after correcting the tension. The next time you clean & sharpen your chain, after some real wood cutting, see If the "Burr" has re-occurred or see If it is No longer there.
Again, Just another piece of information that many chainsaw people ignore, Keeping the bar "Burr Free" also makes it much safer handling the bar when changing chains or doing maintenance, which also by the way should be done with gloves on any way.
Karla
PS. Sorry to be so wordy, but I do see alot of chainsaws with this problem.
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