ms170 me likey! new pickup
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Yes that's very much bad... it needed replaced a long time ago...
Example of a guy that didn't know what a bad rim sprocket was; on another forum (not wood/forestry related) a guy posted that he was having trouble with his chain tension. He would tighten it properly and as soon as he cut a little it would get really loose. Must have been 20 people that all chimed in and told him his chain tensioner was bad. I told him that he should check his sprocket before doing anything else. I had to show him some picture of a worn sprocket so he knew what to look for. As it turns out, it was, in fact, his sprocket. The chain doesn't "seat" down into the grooves when you change a chain etc but once it's run a bit the chain 'settles in" and loosens up. It's a very good indicator of a worn sprocket. Anyways, he had no idea that the sprocket was a wear item, now he knows.
Question. So on my ms290 my Oregon bar and chain are .063 and my stihl is .050. Does this matter for the sprocket or is the pitch the only thing to pay attention to on sprockets? Both are 3/8 but noticed today that the Oregon bar and chain guage is different than the stock stihl bar and chain.
Clutch sprocket doesn't care what gauge the chain is. Sprocket does care about pitch. There are 2 different 3/8 pitches - reg and Lo-Pro (Pico) - they can't be interchanged. Pitch is about driver shape and size, not just distance between links.
Ok thanks. Do you think mine are pretty bad? I'm gonna order some sprockets with way just wondered if they looked Terrible.
IMHO, yes, yours is toast. That saw has been run a LOT.
Regarding gauge and sprockets: sprockets don't care when they are new but if you swap chain gauges back & forth, or change gauge without changing sprocket the wear pattern on the sprocket will be different and will certainly cause problems (most notably abnormally fast wear on the drive-links of the new chains).
The wierd this is that the photos I linked are on a saw that I know hasn't been run much lol. If a lot means aboutn15-20 hours then I suppose so. I looked at 4 other saws today when we were cutting and even one that was rather new has similar grooves.
It's been awhile since I had a saw with a spur sprocket on it so I'm having a hard time remembering how it looked after a few months of cutting but to my recollection they start out smooth, so that one looks very worn.
Spur sprockets in my opinion don't foster as well of a fit with the chain as a rim sprocket. I think they are prone to quick wear. If you ask me I think all saws should come with a rim set up. Some people do switch them out but any sprocket will eventually wear out.
As to if 20 hours is a lot of use, it's hard to say. Some people are harder on equipment. With small saws , some folks try to cut much bigger wood than perhaps the saw was designed for and the oiler can't keep up and the chain gets run dry in the cut. It happens all the time, and that puts a lot of stress and wear on chain links and sprockets, etc. I've seen a guy cut up a whole oak tree with a 170 that was 25 inches at the base. Sure the saw will do it, but the engineers who designed it never intened for it to be used like that. So wear items in that example will wear quicker that they would on a bigger saw.
I know it's common sense to many of us on this forum but when you buy a used saw, especially a small one like the 170, who knows how the previous owner treated it. Cutting big wood never bothering to pull out of the cut to make sure the tiny oiler output is keeping up in the 25 inch dense hardwood ? Nope most just keep cutting and can wear out a sprocket in one afternoon. And I'm sure someone will say no one pulls out of a cut mid way ! Well if your using a saw like the 170 to buck your 25 inch oak ( happens all the time with the average homeowner who buys a saw to clean up blow down) that little oiler will in fact not be sufficient so it's wise to pull out of the cut, rev the engine get some oil back on the chain before it gets too dry, then go back to finish the cut.
So in that case 20 hours is a ton of use. If you only used a 170 to cut buckthorn all day long then I'd say 20 hours of use is very little.
In the case of the saw in the pictures I'd simply put on a new sproket ( and chain) and be done with it.
Spur sprockets in my opinion don't foster as well of a fit with the chain as a rim sprocket. I think they are prone to quick wear. If you ask me I think all saws should come with a rim set up. Some people do switch them out but any sprocket will eventually wear out.
As to if 20 hours is a lot of use, it's hard to say. Some people are harder on equipment. With small saws , some folks try to cut much bigger wood than perhaps the saw was designed for and the oiler can't keep up and the chain gets run dry in the cut. It happens all the time, and that puts a lot of stress and wear on chain links and sprockets, etc. I've seen a guy cut up a whole oak tree with a 170 that was 25 inches at the base. Sure the saw will do it, but the engineers who designed it never intened for it to be used like that. So wear items in that example will wear quicker that they would on a bigger saw.
I know it's common sense to many of us on this forum but when you buy a used saw, especially a small one like the 170, who knows how the previous owner treated it. Cutting big wood never bothering to pull out of the cut to make sure the tiny oiler output is keeping up in the 25 inch dense hardwood ? Nope most just keep cutting and can wear out a sprocket in one afternoon. And I'm sure someone will say no one pulls out of a cut mid way ! Well if your using a saw like the 170 to buck your 25 inch oak ( happens all the time with the average homeowner who buys a saw to clean up blow down) that little oiler will in fact not be sufficient so it's wise to pull out of the cut, rev the engine get some oil back on the chain before it gets too dry, then go back to finish the cut.
So in that case 20 hours is a ton of use. If you only used a 170 to cut buckthorn all day long then I'd say 20 hours of use is very little.
In the case of the saw in the pictures I'd simply put on a new sproket ( and chain) and be done with it.
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that sprocket is from my ms290. The 170 actually has a bit less wear. I understand about the oiler although I have to say, as long as you keep the oiler working and the hole free from obstruction, they don't have any problem staying lubed even at full rpm.
I completely agree with this logic but there is not enough oil output pressure on smaller saws like the 170 to keep oil ports free from obstruction of saw chips when in the middle of a cut at times. So it's not uncommon for the chain to dry up in the middle of a cut. I've had it happen to me more so on smaller saws before. Some people may not even realize it and it can contribute to increased wear.
When I got my Jonsered 2252 my chain started to dry up in a cut first time I used it. I was surprised since it's a pro saw and not known to have any oiling issues. I checked and the adjustable oiler was turned down to low. I turned it to high and now the saw has never had an issue. But still I check sometimes if I'm bucking big hardwood with it just because I don't want the added wear and tear on the bar, chain, sprocket, etc should the oiler become clogged.
Something is quite wrong with that saw. Wrong pitch chain on the sprocket or something. I don't know what would cause that severe of wear but I can show you a picture of a sprocket with probably 50-100 hours on it with much less wear than that.
CountryBoy appears on to something. Sprocket says .325 and you say you run 3/8 chain. The MS290 came with either .325 or 3/8. Did the dealer sell you the wrong chain?
If I'm reading the posts right I think the op said those pictures are from his 290. I also think he mentioned he has 3/8 chain on the 290? I can see .325 on the clutch drum in the picture. So if thinking this through OP are you running 3/8 chain on the saw in the picture ? If yes, you need to put on a different sprocket to match the 3/8 chain.
That would help explain the deep grooves on the spur sprocket
If the bar and chain are 3/8 and since you need a new sprocket anyways it may make sense to stay with 3/8. But if you need a new bar and chain too, you might want to consider going to .325 set up ( so matching bar, chain, sprocket in .325) with the 290 being a smallish ( not small more like smallish medium) 55cc saw it does a little better with the lighter .325 set up. Yes it pulls 3/8 but it pulls .325 better.
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I miss spoke both of my bar and chain setups are 325 for the ms290. I ran the Oregon l81 on it yesterday with no problems.
The picco setup on the ms170 is the 3/8 pitch sprocket and chain setup. i havent' shown a photo of it, but it's similar wear.
I'm surprised to hear this is not normal wear. I looked at several saws and had my stihl guy look at it and it looks normal compared to what I've seeen. I'm going to order a new one but saw still runs and cuts great. I'm not sure there is anything wrong with this saw other than the fact that I use it.
The picco setup on the ms170 is the 3/8 pitch sprocket and chain setup. i havent' shown a photo of it, but it's similar wear.
I'm surprised to hear this is not normal wear. I looked at several saws and had my stihl guy look at it and it looks normal compared to what I've seeen. I'm going to order a new one but saw still runs and cuts great. I'm not sure there is anything wrong with this saw other than the fact that I use it.
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Sure id love to see a photo.
found a good thread on a different forum where people were posting their wear on the drive sprocket, many of them had the same type of wear marks, some were as deep some were less deep. I also read that after a full day of running a new sprocket you will already show the lines of wear. this could be bad info or it could be rather common.
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anybody use the stens brand replacement sprocket? they have one at my local farm store for the small saw, thinking about buying one instaed of ordering a stihl.
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