Determining if a chainsaw spur sprocket is worn out. 

That is normal maintenace to give that bearing a small dab. Not too much or it will simply migrate to the clutch drum surface.

Glad it helped you out. Many people do not realize a worn spur or sprocket can really affect performance and longevity.

@@NCSU4x4 When I checked my chains today, that I was recently using, I could see the signs of wear just starting on the links. Good thing I caught it in time. Thanks👍🏼

Spur sprockets are pitch specific. You will need to consult with a parts list for your saw and see if it was available in 1/4" pitch. Most likely you will need an aftermarket drum which you may have to get through a carving supply vendor, likely the same one that is selling the dime tip bars.

@@NCSU4x4 thanks for the quick response. I realise the spur sprocket will need to be changed depending on the pitch of the chain. But are the housing (i.e. the metal cylinder connected to the spur (is that called the drum?)) the same width (circumference) for every chainsaw? Or do they vary? Hope that makes sense..😬

@@alid8646 the clutch drum is specific to the saw or saw family. Some models such as the 021 / 023 / 025 / MS210 / MS230 / MS250 are all the same clutch and clutch drum bearing size. So for all arguments sake, clutch drums/spurs are saw specific.

The drivers is the measurement of chain length. If that is wrong the chain will be too long or short for your saw.

@@NCSU4x4 Ahh, Excellent. Now I know. Thank you for that explanation. Much appreciated! 👍

Twice.

Some of the older saws ran the roller bearing in a tight race in the drum. Newer saws run the setup you saw here. I'd gently push the bearing in the new drum, grease it, and never look back.

@@NCSU4x4 I never got a notification of this reply. Damn you utube. Butni managed to source from onenplace a new sprocket with an integrated bearing. But, good to know that I could have gotten away with gently tapping the old bearing back into the new sprocket. Brilliant vid and response from the channel owner. Many thanks. Thumbs up.

Think of a chain as a straight length. If you start out at a length of ~40 inches when new, when you add the wear of every bending joint, when your chain is "worn out" it has gained length. For an average 20" 3/8 pitch chain you could easily pick up 0.720" wear / gained length with only .005" wear per pivot pin on 72 drivers. Ok... so the chain drivers are now all more distant ... instead of being 0.375" between drivers you can change to 0.385" or greater. The spur drum or rim sprocket wears to accommodate this chain of pitch. When you install a new chain all of a sudden the driver spacing of the chain does not match the drum. Also add in the tops of the spur sprocket or rim sprocket decrease in diameter. This adds another changing dimension. I will try to do a video to show this. I think that is the easiest way to see and hear leading to understanding.

Some side to side is acceptable. Generally when the clutch engages everything finds its "happy place"

It depends on the saw. Some have an option and some do not. Some saws that do not have an option from the manufacturer do have the option through aftermarket companies such as Oregon.

They didn't realize it was a problem. Saw came to me for other issues and I found it as I was going through the saw..

@@NCSU4x4 That makes even worse. They never noticed it gradually getting more difficult to spin the chain freely each time the chain needed adjusting.

I appreciate it. Pushing pieces of equipment out takes priority over camera work... but I have looked at some different setups than a cell phone.

Poulan setup is not terribly different. Same basic setup. The biggest difference is the bearing is captured in the clutch drum. Check the chain brake is releasing and not hung. Often the brake is left on, clutch slipped, and then the plastic surround melts to the band or melts in the way of the band keeping it from releasing. Check for deformed or dark colored plastic around the clutch drum.

@@NCSU4x4 Thx very much, I think I understand. I really think that's what happened inside there. I have to take the tiny O ring off and take a look inside. Is it fixable or buy another saw? Thank you.

@@dontswin generally those saws are not worth the effort to repair. I saw a report years ago the designed life span of them was less than 15hrs. For most light home owner use, thats more than 15 years of trimming tree limbs and miscellaneous small tasks. If you get to using them for firewood or other continuous duty tasks they quickly fail. I generally suggest looking for a better quality saw for that type of work.

@@NCSU4x4 I'm fairly certain something to do with the clutch brake plastic pc. inside there melted causing it to seize, like you said. I don't know if I take it apart have the skills to get what I need and get it back together again. I already spent $50, lol. THX , for all your help. I guess I should find another saw.🤔🤯