General Product Question
I have a Husqvarna 450e. When I go to cut the tensioner...escalated
General Product Question posted March 10, 2014 by Brian Williams
209 Views, 5 Comments
Question:
I have a Husqvarna 450e. When I go to cut the tensioner seems to loosen alot allowing the bar to move and the chain to sag. I have the pieces lined up correctly in the bar and the tensioner but it still loosens. Any thoughts?
Answer
Brian,
There are a number of possibilities, but one that comes to mind is a bad or worn out drive sprocket or bearing. I would remove the clutch cover, remove the bar and chain, remove the drive sprocket and give it a thorough inspection. Its also a good opportunity to thoroughly clean everything up under the clutch cover and drive sprocket.
You are looking for a worn groove in the drive sprocket gear, If you find it to be worn I would recommend replacing it. Also clean and thoroughly Inspect the sprocket bearing which could also cause this problem, I found one bearing where one of the needles in the bearing went missing, and this will definitely cause some problems, where the chain gets loose, and then tight. The bearings are usually very reasonable, like $5.- so you may want to just replace it If you have been using the chainsaw for a few years. You did not say how old, or how much use you have on your chainsaw!
Also, If you are going to replace your drive sprocket, I would definitely recommend "Oregons" PowerMate system which is a rim and drive sprocket, they are a couple dollars more than the standard drive sprocket but in the future all you need to replace is the "rim", and you can usually get them for about $5.- too.
Here is a link to the "Oregon" PowerMate drive Sprocket system, I really like this system, and it will fix and prevent alot of problems.
/pdf/pro/products/sprockets/pro_main_sprockets.htm
I hope this helps. and please let me know if you have any other questions.
PS. I am Not a Husqvarna Representative or an Authorized Repair, just a experimental chainsaw person.
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Brian,
Also after thoroughly cleaning the drive sprocket bearing, don't forget to relubricate the needle bearing, but do not get any grease or oil inside the clutch, that should remain dry and clean. I use Lithium grease sold at most automotive stores in small tubes, it works great.
Again, I hope this helps, However If you still have a problem than give me a shout!
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The saw is about two years old and I use it sparingly, really not a pro or anything so I haven't used it much. We recently had a bad ice storm so my yard is now a target rich environment. It ran fine over the weekend but yesterday was when this problem surfaced. I checked again and the sprocket did seem to have a bit of wear on it, I am just surprised that something like that could wear out so soon. If this part is an upgrade then I am definately going to replace. You think the adjuster thumbscrew is messed up for the tensioner device as well? I was able to loosen the bar with the knob tightened all of the way, and I really tightened it down. Just seems so weird to me that it is able to do that. This is my first chainsaw so this is a huge learning curve for me, I have never really used one in the past other than a few times.
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Brian,
First, I missed the fact that it was a model 450 "E", So it has the easy one knob tensioner ? Next, Only 2 years old and Not a lot of use, I would probably say that your problem is Not the drive sprocket, and could very easily be the tensioner. Also just my own recommendation, on replacing the Sprocket with the "Oregon" Power Mate but since yours probably doesn't need it I would just make a note to yourself in your manual to look at how the power mate rim and sprocket works, and its definitely a much better system and drive sprocket, when you need to replace it down the road. Is it possible you could take a close up picture of your drive sprocket, and post it, then I can better tell If it has a lot of wear ?
Back to the tensioner, I have not taken a tensioner apart from a "E" chainsaw, so I will have to look at the IPL drawing and some parts to see what could be worn, or may need replacement on the tensioner. I suspect that some of the parts like the Knob and maybe gear that turns the tensioner are a combination of plastics and Metal, so it is possible there is something worn.
I will get back to you latter today, after I do a little research.
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Brian,
Ok - I have looked at the tooless tensioner, and about the only problem that I can see, is it is very important to keep all those moving parts thoroughly clean , and lubricated so that they move easily. A little bit of dirt, and the tensioner will seem like its getting tight enough but its really probably Not.
I have included a parts picture on the attached file, taken from a Model 450E IPL drawing, I will also give you the link to the entire IPL parts list:
/images/ddoc/HUSI/HUSI2011_AAaa/HUSI2011_AAaa_450E_2013-12.pdf
Next, here are the parts I would clean and re-lubricate. First the tensioner bolt and gear parts 11 & 16 of second picture, these need to turn very freely, and lightly lubricated.
Next part 12, the thumb wheel and gear, which mate with part 11, also needs to move freely. That should take care of the tensioner working properly, also Note: the tensioner simply moves the bar back and forth and should "Never" be very tight unless something is wrong. The tensioner also should Not be so tight that the chain does Not have any slack in the chain, maybe about the thickness of a dime or a little less, the chains drive links should be in the groove, and not hanging way down but Not real tight either. (PS. I hope that makes sense) You may be trying to tension the chain too tight, don't do it, just back off a little on the tension.
Now, onto the part that could be the problem, again clean and lubricate everything But in Picture 1, part 18, is the actual clamping force that holds the bar in place and is turned by the flip knob on the clutch cover, this needs to be as tight as you can make it without obviously breaking it. This is the part that holds the bar inplace from moving after it is properly tensioned. By cleaning and re-lubricating the parts associated with item 18, you will make it easier to exert more force to the part that does the clamping of the bar if everything is clean lubricated, and moves freely.s
Also obviously when everything is clean, Inspect all the part, if the plastic gears are starting to get mashed down or deteriorated, then those parts will need to be replaced, or if any parts do not turn freely after cleaning then you will need to fix that problem.
I hope this helps, but Please give me a shout if I can be of any additional help.
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