Just had this same problem on an old Sears 2.0 saw. I got a "new Husqvarna" sprocket on ebay and it was tight, then loose. Tried another sprocket from the same seller and same thing. Tried a new chain, then different bar, same thing. I machined a fake shaft and checked runout on my lathe - a couple sprocket teeth were .012" higher than the others and the drum had a wobble to it. I got a different sprocket and it was fine. Running it may loosen it up as already mentioned. I didn't want to run mine in case the seller wouldn't take it back.
Tight/loose spots new chain, sprocket, and bar.
- Thread starter Vir1dis
- Start date
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Put a mark on the side of the sprocket. Rotate the chain by hand, not turning the engine. (Remove the starter cover and hold the engine stationary by the flywheel). See if the chain tension changes and how that relates to the mark on the sprocket. If the sprocket is out of round this would show it and the tight spot will be with the mark at the same place each time.
You can then do the same test with a mark on the end of the crank. Keep the chain stationary and turn the engine. If the crank is bent then the tension will change.
You can then do the same test with a mark on the end of the crank. Keep the chain stationary and turn the engine. If the crank is bent then the tension will change.
Im suspecting China is involved in this stuff.
Could very well be? I've never had a problem with actual Oregon or Stihl. Rotary and stens have been ok also but I don't know where they are made.
Pulling the starter does rotate the crankshaft but it doesn't turn the clutch drum or chain because the clutch is not engaged. It's just turning in the clutch bearing. This made me think about my saw. My crankshaft can't be causing my issue. I'm going to pull my clutch and rim again and check them out closer.
I bought some.325x7 rims on ebay that said Oregon and had Oregon stamped on them and they came in little baggies that had made in China stickers on them. Pretty sure they are china knockoffs. I didn't have any problems with them though.
I missed this the first time. Your problem is the new sprocket.
Some axial play is normal.
When you install a circlip or E clip that is stamped steel (like many modern chainsaw clutch retention clips), note that one side of the clip has nice square edges and the other side has rounded edges. Install the clip so the square edges are taking the force. In this case the square side goes out. It's less likely to get dislodged this way.
Rooshooter
ArboristSite Operative
Out of round rim sprocket, husky probably having them made in China.
I think he has a spur drum.
Yeah I have a spur sprocket.
I will get some calipers on to it to measure it.
You probably don't need calipers. Move the chain by hand until you get to the begining of a "tight" spot. Mark the chain and bar. Continue to move the chain by hand to the begining of the next "tight" spot. Count the number of drive links you moved the chain. That number will correspond to the bad drive sprocket or bad bar sprocket. The two sprockets will have different tooth counts
It's a consistent 4 teeth from tight to tight again.
Do you by any chance still have the old bar and chain. If you do there is the process of elimination. Change the chain, check results. Old bar with new chain, check results. In other words, change one thing at a time and see if issue goes away.
I don't have any other bars to compare with.
However, I am not sure if this is normal but when I tighten the the nuts on the clutch cover (yes I hold the bar tip up as I do so) the chain tension increases.
If this is not normal then something is perhaps tilting the bar (on the z or y axis, I don't know)
I have now noticed that the chain likes to shift across the clutch sprocket, so the 4 links gap between the two tight spots could be the bar making the chain move along the width of the sprocket and then slip back to where it started every have revolution or so of the rear sprocket?
I don't know what could cause the bar to move when tightened.
Just get a different made sprocket .
The tensioner pin is tapered. If the pin isn’t completely in as you tighten the nuts, the chain gets tighter.
I’d run it for a few and recheck. This is quite common and it goes away usually after a couple revs.
Making a bit of a mountain out of a mole hill
It seems to happen every time.
The chain tensioner has a tapered pin that fits into a hole in the bar. (Mentioned above) Are you sure that the pin is aligned with the hole in the bar BEFORE you start to tighten any bar nuts. If the tapered pin does not enter its designated hole, it will prevent the bar from seating flat against the saw body and cause a mis-alignment
The chain tensioning pin is definitely in the hole.
The bar might be sitting correctly after all, whilst holding the bar tip up the chain still went tight loose tight every 4 drive links with the clutch cover nuts loosened.
The chain is definitely drifts side to side along the sprocket (not smoothly either) and I think that it's causing the tight and loose spots. What is causing that has me beat.
Thank you everyone for your help, I really do appreciate it.
Who installed the clutch drum and clutch? Are the clutch washers in the right places? If that is correct, I would tension the chain to where it's tight but can still rotate by hand, tighten the bar nuts and run it a little while and check it again.
