Bar's sprocket is freezing

[thenne1713]

Don't they have needle bearings?

My mistake, Ball, needle, or roller, they are bearings vs bushing/ non-roller, it is a bad bearing, not repairable by the owner if bad, only replaceable if they wish reliable, (and considering the topic content, maybe skeptical of that statement,

 

[Sidecarflip]

Roller tips have a ball bearing, and you have a bad tip. If bar is solid, you will need to replace the entire bar, but if bar is two-piece, you can replace just the tip w/ roller sprocket. I recall reading one complaint some years ago the guy thought he had engine issues on a new saw, finally realized it was roller tip seizing causing his issues. It can happen, but I imagine MOST tip issue start with being pinched/ bound when downing or bucking. A simple 2-3-feet or longer of a 12-inch log can exert tremendous crush.

All my bars have replaceable (riveted on) roller noses that can be easily replaced if they fail but candidly, none have ever failed me. I keep the sprocket nose greased, I don't plunge cut unless absolutely necessary and I clean not only the oil holes in the bar when I flip it or renew a loop but I clean the bar groove with an old, expired credit card as well. If a bar (without a replaceable nose) don't have a grease hole (port) in it. it won't be on any of my saws, ever. I see Stihl is eliminating the grease hole but they are still there on every Echo sold. Not sure about Husky however as I don't own one.

Don't believe I've ever replaced a bar unless it's worn out, that is, it's lost the slight radius or what I term 'rock' in the long surface and I cannot grind it back in because there isn't enough 'meat' left in the bar to keep the drivers from contacting the base of the bar where the side laminations end. Without 'rock. the bar cannot present the teeth at an angle to allow them to cut (to the depth of the rakers or depth gages. Flat bars don't work, have to have the 'rock' in them and that rock decreases as the bars are used for a prolonged period of time...

I know that sound involved, but it really isn't and you can easily see the rock if you look at a new bar sideways where you can see the bar in a flat plane, not sight down the bar looking at it from the end.

 

[Sidecarflip]

The ones that I have disassembled have roller bearings.
View attachment 1193766

Philbert

Same, same and the 'hole' in the bar aligns with the bearings as well. Least mine do and in my case, I inject grease in it while pulling the chain alone to rotate the bearing and grease it.

 

[Chainsaw Pete]

I imagine MOST tip issue start with being pinched/ bound when downing or bucking. A simple 2-3-feet or longer of a 12-inch log can exert tremendous crush.

I suspect you are right on the cause of this problem. I have, on several occasions, had the saw bind in the cut as the log moved. The tip has almost always been outside the log (on the far side) when this has happened, but I honestly don't remember the details of all my tree cutting with this saw.

 

[Chainsaw Pete]

You sharpen the chain after every use? Interesting. You must be really abusive on a chain or stick it in the ground or something. If I sharpened a chain after every use, I'd soon not have any cutter teeth left to sharpen and I do hope you are lowing the rakers an appropriate amount as well, using a raker gage. Secondly, why do you empty the saw of bar oil and gas? Seems really odd to me if you are planning on using the saw again in the foreseeable future. Only time I'd dump the fuel and certainly not the bar oil is if I was storing the saw, long term. something I don't do anyway, as I use canned fuel which has a viable life of at least 2 years and sometime longer. Bar oil i reality, never goes bad, why dump (waste) it. What you are doing seems strange to me.

Not with my grinder. I use a few strokes of a file in the field or with the saw clamped in a vise in my basement. After several hand sharpenings, I do use the grinder. I aim to just barely touch the spinning stone to the teeth.

As I said, I'm a homeowner, not a pro, and I use the saw mostly to clear downed trees or take down trees for friends. I don't plan on using the saw - a need arises and it goes into service. Sometimes (usually) it can sit for months between uses. I use a funnel and the gas and oil go back into their original containers. I also run the saw's carb dry by letting it idle. My experience with both saws is they start right up after being fueled this way. When I left the gas in the saw between usages, the saw was harder to start - much harder requiring a lot of pulling on the recoil rope.

Oil draining is done because the 250 leaks oil if I leave it in the saw. My dealer said this was very common. If you guys do not have this problem, I'll dig into why and where the oil is escaping. With a full oil tank, I'll have liquid oil pooling on newspapers under the saw in two or three days.

 

[dboyd351]

possible mismatch in pitch between Bar and chain?

 

[AxFan20]

I'm running a Stihl MS250 with the original 18" OEM Stihl bar. I'm a homeowner who helps out friends with downed trees or trees that need to be taken down. The last three times I used this saw, the nose sprocket on the bar froze solid - the chain would not move. After every use, I sharpen chains, pull off the side cover and clean out wood shavings and sawdust, and empty the saw of gas and oil prior to putting it away.

When the sprocket freezes, and sawing is over for that saw, I've pulled the bar, cleaned out the slot, oil hole and as much as possible around the sprocket. Then I've squirted WD40 around the nose, and by pressing the sprocket on a piece of soft wood (usually and old 2x4) and pushing back and forth, I have managed to loosen the sprocket and get it to turn freely. I also spray WD in behind the tip to loosen/wash out any dirt. After cleaning, I lightly oil the tip (WD is not a long life lube). While sawing, I use Stihl bar and chain oil exclusively (orange gallon size) and it seems I'm pumping about 1 1/2 reservoirs of oil to one full tank of gas - that has been consistent since the saw was new and tells me the pump is working. If I start the saw up, put a piece of clean cardboard just beyond the tip I get a light spray of oil as the chain rotates - oil is being pumped as designed. I stop and file the chain if it seems to be cutting slowly, and after maybe 3 or 4 hand sharpenings I use an Oregon chain saw sharpener to keep the proper chain profile.

I've had NONE of these issues on my MS311 (but it gets the same cleaning/sharpening/maintenance).

What is causing the nose sprocket to seize up on my 250? It seems to happen after a couple of tanks of gas. The wood I have been cutting is mostly downed trees, sitting up off the ground (not dirt encrusted logs), mostly hardwoods. Chains vary from Stihl to Oregon, though I doubt the chain is a contributing factor.

Here's my .02. WD40 is an excellent penetrant and cleaner. Terrible rust preventative. Bad lubricant except for very fine uses. I believe you have cleaned the tip bearings dry with WD40. Is the tip hot when it seizes ? Someone else mentioned that the hole at the tip is for GREASE -correct. Try to dry the bearing with air but do not let it Whine. Never let a bearing whine with air. Grease it if it has a hole. Turn the spur and grease it again. If you don't have a hole there, try to soak bar lube between the teeth. Slowly turn the spur and add more lube.
At a certain point try another bar, you have two spare, and throw this one out. I would suggest you never use WD40 on a bar tip

 

[cookies]

The bearings and their pocket are worn out, you have bearings jamming on top of each other in the pocket locking the sprocket. This is dangerous and will cause a thrown chain or even break a chain. Do not be cheap with chainsaws, replace whats worn or risk death.

 

[gggGary]

clean the bar groove

This!
I use pick made out of old windshield wiper stainless and clean the groove and the oil passages when flipping the bar.
Ps windshielkd wiper stainless makes the BEST little specialty tools! bends and grinds easy holds a shape and edges nicely.

 

[Wizard]

Here's my .02. WD40 is an excellent penetrant and cleaner. Terrible rust preventative. Bad lubricant except for very fine uses. I believe you have cleaned the tip bearings dry with WD40. Is the tip hot when it seizes ? Someone else mentioned that the hole at the tip is for GREASE -correct. Try to dry the bearing with air but do not let it Whine. Never let a bearing whine with air. Grease it if it has a hole. Turn the spur and grease it again. If you don't have a hole there, try to soak bar lube between the teeth. Slowly turn the spur and add more lube.
At a certain point try another bar, you have two spare, and throw this one out. I would suggest you never use WD40 on a bar tip

WD 40, I understand, stands for Water Displacement formula # 40. It's not a lubricant, and in my opinion, although it displaces moisture, might also attract moisture. I understand it is also di-electric, which would mean it doesn't help conduct electrical current.

Food for thought.

 

[Chainsaw Pete]

Here's my .02. WD40 is an excellent penetrant and cleaner. Terrible rust preventative. Bad lubricant except for very fine uses.
At a certain point try another bar, you have two spare, and throw this one out. I would suggest you never use WD40 on a bar tip

I use WD as a solvent and pressurized cleaner. I know enough not to use it as a lubricant - if you spray it on a surface, in a couple of days it is gone. Try that with oil. The only alternatives to WD for cleaning out the tip would be a degreaser or solvent - think kerosene, acetone, etc. and those are worse unless I am trying to depitch the tip from pine resin.

Based on what I've learned here, I'll change bars and probably do a PM on the old one to see what if anything is wrong with the bearings - like @cookies said.

@gggGary - I've made a hooked pick that slides easily down the bar out of a scrap of stainless steel sheet metal that I found. I've also used dental tools. My dentist saves his broken tools for his patients - pottery people love them, I've asked for them and use them to clean out crud in chainsaws, motorcycles, and almost anything mechanical. Most of the dental scalers and picks are hardened steel, but I've ground them for various purposes. Next time you see your dentist ask...he is charging you enough anyway.

@dboyd351 - No mismatch on chain and bar.

 

[blades]

crack the oil tank open when through using . helps relieve back pressure a bit

 

[Philbert]

Bar groove and oil hole cleaner.
With friends.


Philbert

 

[SteveSr]

Oil draining is done because the 250 leaks oil if I leave it in the saw. My dealer said this was very common. If you guys do not have this problem, I'll dig into why and where the oil is escaping. With a full oil tank, I'll have liquid oil pooling on newspapers under the saw in two or three days.

The only seal in these oil pumps are the machining tolerances of the piston and bore and the viscosity of the oil. Daily temperature swings will pressurize the tank and push oil out. The only way to stop this is to limit the temperature swings or empty the tank.

The next time you free up the sprocket on your old bar grab two opposite teeth and see if you can shift the sprocket around either inline or perpendicular to the bar. Any noticeable movement says that the bearings are shot. You will also see this if the chain tie straps are dragging on the bar nose. put up a photo of t he bar tip with the chain properly tensioned.

 

[muddy42]

I'm running a Stihl MS250 with the original 18" OEM Stihl bar. I'm a homeowner who helps out friends with downed trees or trees that need to be taken down. The last three times I used this saw, the nose sprocket on the bar froze solid - the chain would not move. After every use, I sharpen chains, pull off the side cover and clean out wood shavings and sawdust, and empty the saw of gas and oil prior to putting it away.

When the sprocket freezes, and sawing is over for that saw, I've pulled the bar, cleaned out the slot, oil hole and as much as possible around the sprocket. Then I've squirted WD40 around the nose, and by pressing the sprocket on a piece of soft wood (usually and old 2x4) and pushing back and forth, I have managed to loosen the sprocket and get it to turn freely. I also spray WD in behind the tip to loosen/wash out any dirt. After cleaning, I lightly oil the tip (WD is not a long life lube). While sawing, I use Stihl bar and chain oil exclusively (orange gallon size) and it seems I'm pumping about 1 1/2 reservoirs of oil to one full tank of gas - that has been consistent since the saw was new and tells me the pump is working. If I start the saw up, put a piece of clean cardboard just beyond the tip I get a light spray of oil as the chain rotates - oil is being pumped as designed. I stop and file the chain if it seems to be cutting slowly, and after maybe 3 or 4 hand sharpenings I use an Oregon chain saw sharpener to keep the proper chain profile.

I've had NONE of these issues on my MS311 (but it gets the same cleaning/sharpening/maintenance).

What is causing the nose sprocket to seize up on my 250? It seems to happen after a couple of tanks of gas. The wood I have been cutting is mostly downed trees, sitting up off the ground (not dirt encrusted logs), mostly hardwoods. Chains vary from Stihl to Oregon, though I doubt the chain is a contributing factor.

I have had similar issues to you – seized bar nose sprockets. This was a Stihl 088 and MS460 with OEM Stihl bars (20, 25 and 36 inch Stihl Rollormatic stihl bars respectively. The bars are pretty new and are still on their first chains. I do as you do and clean the bar grooves out regularly. I also cleaned out and checked the oil tank and oil pumps everything was fine. Similar to you the bar threw off oil from the tip. Odly a smaller saw (MS260 with a 16 inch bar) was unaffected by this issue.

It remained a bit of a mystery that was only solved when I switched brands of bar oil. I was using rotatech and have moved back to Oregon. I am not sure but I think the rotatech oil was too thick and it wasn’t oiling the middle of the bar nose sprocket properly.

Hopefully I havn’t caused any long term damage. I soaked the bar noses in diesel and bar oil combination. I always have adjustable oilers set to maximum

 

[stihltech]

Clean all you want. Replace the bar.

 

[lone wolf]

Clean all you want. Replace the bar.

That will do it!

 

[muddy42]

Clean all you want. Replace the bar.

Even bar deserves to be cleaned and maintained. I will replace a bar if I think a bar has had permanent nose damage, however in my view they can survive a bit of abuse as long as they are not overheated or chipped. Bars should last for 2-4 chains not 1/2 a chain. In the longer bar lengths I have replacement tips waiting for that day.

 

[lone wolf]

Even bar deserves to be cleaned and maintained. I will replace a bar if I think a bar has had permanent nose damage, however in my view they can survive a bit of abuse as long as they are not overheated or chipped. Bars should last for 2-4 chains not 1/2 a chain. In the longer bar lengths I have replacement tips waiting for that day.

Bars last way more than a few chains.

 

[muddy42]

Bars last way more than a few chains.

They probably do, mine normally go after user error - chipped or bent.