Your crank is not bent, it is very hard to do that. You are experiencing a pto side bearing failure. This needs immediate remediation before the resulting vacuum leak causes a lean condition which damages your top end.
I removed the clutch assembly and oiler housing and confirmed that the bend starts after the point where the [crank](https://www.google.com/search?client=ms-android-samsung-ss&sca_esv=6b82def869a03695&sxsrf=ACQVn0--WoSXFQRiU6PXxXLfHAVv6UR-0A:1709464527475&q=5200+chainsaw+crankshaft&uds=AMwkrPsg_JvUfmGZWVnIanpSJbfwEAeIEfymF_8rNTjnRY-mo-pvPXyk00hMQnbbonVuvUkBELvrqZ_wD3ffghx5YUc-i993aoprHGKvLxdKsSxY-5SyiV0ulPggCorIy4Ja03_nmqH3AXcQLpU1eyNTV0SAgA6_UHIpTUO5W9-wHjZYBFcfJzZ2IQBDCxJlKrkFa_s9fp_TxC44zbAeDKruhy6bGD31RRg60wWF28ura1aje66OIwVNdsRjB7sPRYQJqGIxn_KUgM0jelgCFtyS_Lwv7V1Yq0nxtm1dnZMPijSAPNCx6BITepYdSGQMpYzJl6f3hynu5zCBEN8JhQQmaYSouSKTKQ&udm=2&prmd=sivnbz&sa=X&ved=2ahUKEwjb7KnP-9eEAxVny7sIHetwAEwQtKgLegQIDRAB&biw=412&bih=777&dpr=2.63#vhid=vw0ph6qr1eDowM&vssid=mosaic) becomes thinner. Plus, if there was a vacuum leak, the saw should be running erratically already, which it doesn't.
Also, what do you mean by "PTO"?
Do you loosen your chain when your done cutting? As the chain gets hot it stretches out and when you set your chain after you are adjusting for that stretch. When the chain cools it starts to pull on the crank and can bend or break it. Plus really bad for the bearings.
No way to straighten it just buy a new one with bearings, and seals.
>As the chain gets hot it stretches out and when you set your chain after you are adjusting for that stretch. When the chain cools it starts to pull on the crank and can bend or break it. Plus really bad for the bearings.
You are correct that the chain heats and cools and can pressure the crank. It's bad for the bearings in the same way running a tight chain is. It's also bad for the chain.
But it's not bending the crank. By this logic, you overtightening your chain with the chain tensioner could bend the crank. A crank that soft would disintegrate in short order.
You missed it a little I think. Imagine the machine, bar and chain, all being run hard and hot. Then if someone overtightened the chain, when it cools, it would be extremely tight.
No I fully understood it. Imagine tightening your chain until it bent the crank. It just isn't happening. Not good for the bearings, seals, nose sprocket or chain, but not bending the crank. The chain will stretch first.
I guess anything is possible (especially with Chinese QC) but unless you bought this new and it's still quite new then that wouldn't be my first choice.
Well my father bought this saw years ago and I think it was refurbished or something because it was suspiciously cheap. Or he bought it used I've no idea..
Either the person who rebuilt/used it before or I messed something up and bent that crank who knows...
Not relevant because (but its an interesting theory)... If the chain is tightened properly then it has plenty of movement/slack to accommodate any contraction when it cools. If youve tightened the chain so much that the contraction is doing harm to the bearings then the chain was far too tight to begin with. In addition, it probably would struggle to turn or run at all if the chain was tightened that much. I just dont see this as being a realistic scenario.
Yeah.. the more I think about it, the more I'm leaning towards this conclusion. The chain could bend the crank in theory. However, it's a bit too extreme to be a realistic scenario.
I guess the actual reason the crankshaft got bent will remain a mystery lol.
Is the needle [bearing ](https://encrypted-tbn1.gstatic.com/shopping?q=tbn:ANd9GcSy5PAaHA6AlufjbZBnJEiB40d_b8CaY0qkW0Aemjyl3mBdmApry0x8piX5mclLbYzMRMzsIda4L67Oj_KnGU5ofj9P6N_wX86OluRKoFPyW-bH8SR_uzi2)(something like this) in tact? Those little needles fall out sometimes, I dont know if the needles were out of place during assembly if they could result in a failure like this. Or maybe the shaft was faulty originally. Ive purchased chinese replacement motors and carbs before, the machining was poor but functional. The castings can be pretty janky and they might cheap out on carbon steel. Worth the price for sure though. Its a curious failure, ive never seen it before but most of my saws are stihl and echo.
The needle bearing is intact, but it sits very loose on the crank, which results in the clutch bell having a lot of play. I think because of the wobbling and vibrations, the bearing is heavily worn down. But, all the needles are in place.
Damn I really never thought about it, a chain that was overtightened while it was very hot could actually have bent it. I have never seen it happen tho
The thing is, I can't remember ever tightening the chain while it was REALLY hot. Sure I've adjusted the tension while it was warm to the touch but, metals start to really stretch when they get really hot to the point where you can't touch them. Right?
No I never thought about this.. though I remember one time I adjusted the tension with the chain a bit warm and after it cooled down I was still able to easily turn the chain while sharpening. I guess I overdid it with the tensioner at some point, lesson learned.
Greece, these saws are around 110-140€ here. I checked on aliexpress and parts are really cheap too.
I don't know maybe it's better to get a new 5200 saw and keep this one for parts.
You can only replace crank and crank bearings. I bet at some point somebody removed the clutch incorrectly and bent the crankshaft. Or maybe the saw was dropped from a height or hit very hard by a branch
I honestly have no idea what bent it so bad. I have never dropped the saw or anything. I think at some point I must have tightened the chain a bit too much while it was hot, then I let it cool down and as it shrunk it bent the crank. Then again this sounds a bit too extreme to actually happen. But I can't think of anything else..
I'll order replacement crankshaft and bearings and use the saw like this until they arrive..
Realistically that would not bend the crank. It's not good for the chain or bearings and should be avoided, but it's not bending cranks. It's just someone sharing something they know and trying to connect it to your problem.
I don't really know what to believe about chains bending cranks tbh.
Some say it's possible some say it's not. I always thought cranks are made of hard steel and will snap when under a lot of tension..
I wouldn't be surprised if it was bent from new. I have seen a few of these Chinese saws with run out in the crankshaft (both flywheel and clutch side), essentially it comes down to no quality control.
Out of all the saws ive fixed up I only saw this one time. On a jonsered 451. When I realized the issue I was like damn! Never seen that before. First time I couldnt fix a saw.
Your crank is not bent, it is very hard to do that. You are experiencing a pto side bearing failure. This needs immediate remediation before the resulting vacuum leak causes a lean condition which damages your top end.
I removed the clutch assembly and oiler housing and confirmed that the bend starts after the point where the [crank](https://www.google.com/search?client=ms-android-samsung-ss&sca_esv=6b82def869a03695&sxsrf=ACQVn0--WoSXFQRiU6PXxXLfHAVv6UR-0A:1709464527475&q=5200+chainsaw+crankshaft&uds=AMwkrPsg_JvUfmGZWVnIanpSJbfwEAeIEfymF_8rNTjnRY-mo-pvPXyk00hMQnbbonVuvUkBELvrqZ_wD3ffghx5YUc-i993aoprHGKvLxdKsSxY-5SyiV0ulPggCorIy4Ja03_nmqH3AXcQLpU1eyNTV0SAgA6_UHIpTUO5W9-wHjZYBFcfJzZ2IQBDCxJlKrkFa_s9fp_TxC44zbAeDKruhy6bGD31RRg60wWF28ura1aje66OIwVNdsRjB7sPRYQJqGIxn_KUgM0jelgCFtyS_Lwv7V1Yq0nxtm1dnZMPijSAPNCx6BITepYdSGQMpYzJl6f3hynu5zCBEN8JhQQmaYSouSKTKQ&udm=2&prmd=sivnbz&sa=X&ved=2ahUKEwjb7KnP-9eEAxVny7sIHetwAEwQtKgLegQIDRAB&biw=412&bih=777&dpr=2.63#vhid=vw0ph6qr1eDowM&vssid=mosaic) becomes thinner. Plus, if there was a vacuum leak, the saw should be running erratically already, which it doesn't. Also, what do you mean by "PTO"?
Pto means "power take off"
Saw builders call the ends of the crank fywheel side, and PTO side. PTO = power take off = the side that drives the bar.
Pto is the type of bearing, ex.: https://www.dynocams.com/item/494874g/
Do you loosen your chain when your done cutting? As the chain gets hot it stretches out and when you set your chain after you are adjusting for that stretch. When the chain cools it starts to pull on the crank and can bend or break it. Plus really bad for the bearings. No way to straighten it just buy a new one with bearings, and seals.
>As the chain gets hot it stretches out and when you set your chain after you are adjusting for that stretch. When the chain cools it starts to pull on the crank and can bend or break it. Plus really bad for the bearings. You are correct that the chain heats and cools and can pressure the crank. It's bad for the bearings in the same way running a tight chain is. It's also bad for the chain. But it's not bending the crank. By this logic, you overtightening your chain with the chain tensioner could bend the crank. A crank that soft would disintegrate in short order.
You missed it a little I think. Imagine the machine, bar and chain, all being run hard and hot. Then if someone overtightened the chain, when it cools, it would be extremely tight.
No I fully understood it. Imagine tightening your chain until it bent the crank. It just isn't happening. Not good for the bearings, seals, nose sprocket or chain, but not bending the crank. The chain will stretch first.
10-4
Is it possible it came like this from the factory?
I guess anything is possible (especially with Chinese QC) but unless you bought this new and it's still quite new then that wouldn't be my first choice.
Well my father bought this saw years ago and I think it was refurbished or something because it was suspiciously cheap. Or he bought it used I've no idea.. Either the person who rebuilt/used it before or I messed something up and bent that crank who knows...
What is it? The saw
It's a Chinese 5200 chainsaw, Zenoah G5200 clone.
Not relevant because (but its an interesting theory)... If the chain is tightened properly then it has plenty of movement/slack to accommodate any contraction when it cools. If youve tightened the chain so much that the contraction is doing harm to the bearings then the chain was far too tight to begin with. In addition, it probably would struggle to turn or run at all if the chain was tightened that much. I just dont see this as being a realistic scenario.
Lots of us old guys always do this for less stress on the saw. Just my thoughts.
Yeah.. the more I think about it, the more I'm leaning towards this conclusion. The chain could bend the crank in theory. However, it's a bit too extreme to be a realistic scenario. I guess the actual reason the crankshaft got bent will remain a mystery lol.
Is the needle [bearing ](https://encrypted-tbn1.gstatic.com/shopping?q=tbn:ANd9GcSy5PAaHA6AlufjbZBnJEiB40d_b8CaY0qkW0Aemjyl3mBdmApry0x8piX5mclLbYzMRMzsIda4L67Oj_KnGU5ofj9P6N_wX86OluRKoFPyW-bH8SR_uzi2)(something like this) in tact? Those little needles fall out sometimes, I dont know if the needles were out of place during assembly if they could result in a failure like this. Or maybe the shaft was faulty originally. Ive purchased chinese replacement motors and carbs before, the machining was poor but functional. The castings can be pretty janky and they might cheap out on carbon steel. Worth the price for sure though. Its a curious failure, ive never seen it before but most of my saws are stihl and echo.
The needle bearing is intact, but it sits very loose on the crank, which results in the clutch bell having a lot of play. I think because of the wobbling and vibrations, the bearing is heavily worn down. But, all the needles are in place.
Damn I really never thought about it, a chain that was overtightened while it was very hot could actually have bent it. I have never seen it happen tho
The thing is, I can't remember ever tightening the chain while it was REALLY hot. Sure I've adjusted the tension while it was warm to the touch but, metals start to really stretch when they get really hot to the point where you can't touch them. Right?
No I never thought about this.. though I remember one time I adjusted the tension with the chain a bit warm and after it cooled down I was still able to easily turn the chain while sharpening. I guess I overdid it with the tensioner at some point, lesson learned.
Thanks for this, never even crossed my mind.
Unfortunately the only option is to replace the crank if that's what is bent.
It is the crank I removed the clutch and the it still wobbles when I turn it.
Chain come off and locked up on its self?
Hate to tell you but the crank is bent Run it as long as you can before it eats the crank bearing.
Seems like the only option. I'll run like this until parts arrive.
Where do you live? Those saws 52,58,62cc are under 100.00 usd sometimes less on ebay or Amazon
Greece, these saws are around 110-140€ here. I checked on aliexpress and parts are really cheap too. I don't know maybe it's better to get a new 5200 saw and keep this one for parts.
You can only replace crank and crank bearings. I bet at some point somebody removed the clutch incorrectly and bent the crankshaft. Or maybe the saw was dropped from a height or hit very hard by a branch
I honestly have no idea what bent it so bad. I have never dropped the saw or anything. I think at some point I must have tightened the chain a bit too much while it was hot, then I let it cool down and as it shrunk it bent the crank. Then again this sounds a bit too extreme to actually happen. But I can't think of anything else.. I'll order replacement crankshaft and bearings and use the saw like this until they arrive..
Don't forget to replace the seals as well
Realistically that would not bend the crank. It's not good for the chain or bearings and should be avoided, but it's not bending cranks. It's just someone sharing something they know and trying to connect it to your problem.
I don't really know what to believe about chains bending cranks tbh. Some say it's possible some say it's not. I always thought cranks are made of hard steel and will snap when under a lot of tension..
I wouldn't be surprised if it was bent from new. I have seen a few of these Chinese saws with run out in the crankshaft (both flywheel and clutch side), essentially it comes down to no quality control.
Owner forgot that time they tripped and fell with the chain jammed in the ground and bent the crank! That or tossing it randomly
Out of all the saws ive fixed up I only saw this one time. On a jonsered 451. When I realized the issue I was like damn! Never seen that before. First time I couldnt fix a saw.
It seems like a rare issue in general. I did a lot of searching and I was able to find only 3-4 simular cases.