What do a dead 572 and 500i have in common?

[Skeans1]

I'm interested in knowing how these saws fail in the end. I'm guessing anyone who makes a living off their saw is not straight gassing them. I'm expecting those that are run long and hard with dull chains and caked on dirt end up overheating and end up with scored pistons and cylinders. Those that never have their filters cleaned end up low on compression or with bearing failures. Obviously those with trees dropped on them will have cracked cases or tanks.

What tend to be the most common points of failure, and are those consistent across brands?
How about across users. Does logger A always burn up a saw, whereas B sees failed lower ends?

Curious.

If you're a faller.....you can just feel when a saw is losing its punch. Parts are starting to wear out that become a nuisance. It's not that you can't rebuild the saw.....you just can't gamble on losing scale because the saw you rebuilt has developed some anomaly.

Those saws losing their punch just got sold down the road....usually to a firewood cutter. I had saws when I quit logging and I still have two of them today.

Kevin

Use to be I'd do one top end normally 6 to 8 months after purchase and by the time the second top end was done the bottom ends were getting loose on the 385 as well as some of the 372's. We use to figure on a year on a power head when they were used 5 to 6 days a week 6 hours a day spinning good rpm's before they put all the limitations on them. This was never the fault of the manufacturer it's how they were ran and used for production falling with long bars and aggressive chains.

[Spike60]

Awful lot of my saws are customer walk aways. Saws that failed for one reason or another, that they didn't want to repair. Have to understand that in many people's minds, they'd rather buy a new saw than do a major repair on their old one. But some of them were way too nice to NOT repair them, so I fixed them up for myself. I realize that dealer cost on the parts and zero labor $ is different than what the customer would have to look at. But some of them were in like new condition other than the top end or whatever.

I have a Jonsered 90 that falls into that category, as well as what Kevin mentioned about a non-commercial user buying a big saw for maybe one big tree and then hardly ever using it again because of it's size/weight. More of those saws out there than you might think, and we shouldn't necessarily consider the guy that bought it as being a dummy. In some cases what drives this is that buying a big saw is far less expensive than than a price from a tree company to take down a large tree. A person could be an experienced saw user, but simply needs a larger saw for the task at hand. Then when they realize it'll just sit there and never get used, it becomes a sweet deal for us guys.

Probably posted this before, but the other half of that 90 story is the customer brought it in and said he had it at another dealer and the coil, which is NLA is bad, and traded it on a 2171. (Hey, it wasn't my diagnosis). Couple weeks later I took a look at it, cleaned the points and she fired right up. Ought to take it out and run it, cause it has become a shelf queen being as clean as it is. A good shoot out might be that and it's contemporary 285CD.   

[Wlmedley]

I have been doing mechanic work for 45 years and have found that when I went out to work on a piece of equipment I tended to do better work on a dozer,excavator,what ever,if it was apparent that the owner,operator took good care of it.If I went out on something that was beat to death with oil leaks all over I would fix what the customer wanted and leave but if the machine was fairly clean and in good condition for its age I would give a little extra.Maybe that was wrong but the older I got the more I seemed to do this.I rarely have any thing worked on but if I take anything to a shop I make sure it is clean and has the appearance of having been taken care of because I believe all mechanics probably have this same attitude.

[Real1shepherd]

Use to be I’d do one top end normally 6 to 8 months after purchase and by the time the second top end was done the bottom ends were getting loose on the 385 as well as some of the 372’s. We use to figure on a year on a power head when they were used 5 to 6 days a week 6 hours a day spinning good rpm’s before they put all the limitations on them. This was never the fault of the manufacturer it’s how they were ran and used for production falling with long bars and aggressive chains.

We used to get a yr on the big Huskies. Then Power Punch came out....the first quasi-synthetic oil mix on the market. Bailey's pushed it hard. After that, I started to get a yr and a half on the big Huskies which totally screwed up my pushing them down the chain tactic every yr.:D

Kevin

[ehp]

Believe me when I say some loggers should not run saws  , they are just unreal brutal on them, . I never had a top end go down on me or crank bearings and I run a saw hard but I watch and listen to it when its running . I have had saws show up guys wanted them to be worked on that you could not find the 4 holes in the cylinder to get at the 4 screws that hold the cylinder to the crankcase . Cylinder completely covered is pine pitch and ran so hot it let go 

[ehp]

I'm sure Spike has seen this lots of times but guys bring in a saw and say she runs great but chain will not move when saw is running , crank busted right off at the crank bearing . Seen this quite a few times . Or saw has a funny rattle in it when I let off the throttle , crank broke at the lower rod pin , as long as the saw runs at the same  rpm it does not sound bad but when it comes back down from say wide open they sure rattle . Seen that one to lots of times

[ehp]

stihl 066/660 I seen a ton of this , logger brings saw in and it will not idle correct , if the normal stuff checks out correct pull the bar cover off and check the crank for any up or down movement and take the drum off and study where the crank comes out of the crankcase , Seen lots where the crank bearing either goes or spins in the crankcase causing a major air leak . 

[Spike60]

Rarely see a crank busted off at the end. Occasionally do see that on the 357/359 though. Guy will come in and say, "Hey, my clutch fell off." Yeah, and the end of the crankshaft is still in it.

But it is amazing how a saw can still run when the bottom end is coming apart. That rattle sure is unmistakable though. Then you tell the customer that it's a gonner, and they say, "yeah, but it still runs".

[ehp]

Spike, what I see on broken cranks 99% of the time is from limbing at wide open throttle and the chain brake snapped on , I see some crank out of true mainly at the rod pin of the crank and thats from guys getting the chain stuck and pulling so hard on the saw that it pulls the crank off of being true or straight and what I have found is most times once this has happened the crank will never stay straight again , you straighten it and once you start running the saw it just goes back to being bent