Bar or Chain or something more sinister?

[Aussie MacGyver]

Howdy All

I am still pretty new to chainsaws. I have only cut enough wood for a few weeks of fire at night. I have an old Pioneer 650 that runs pretty good. Problem is that the saw bogs down in a cut and the chains stalls (stops). Lift a bit and the chain will speed up and I can start the cut again. When this happens there is a high pitched rattle and when I rev the saw it feels unbalanced.

Now before I use the saw I adjust the chain, fill the manual oiler and fill with fuel. The chain was sharpened 2 logs ago.

After cutting the chain gets very loose. It will hang well below the bar. I'm sure I am tightening it right. I loosen the two bolts use the adjusting screw to tighten chain until all slack is gone but chain can still be turned by hand. Lift bar while tightening the bolts.

There is quite a bit ofsideways slack in the chain. Would it be possible that the PO has put the wrong guage chain in for the bar?

What should I measure/do?

cheers
Scott

 

[Ekka]

Seriously, take it to a saw shop, sounds all a bit too wierd.

Could be a myriad of things, crankcase seals, bearings, bar nose sprocket, drive sprocket, clutch, carby, mixture etc...

... unless you know what you are doing I'd suggest a saw shop.

 

[NORMZILLA44]

I agree does not sound good, and that is what I would do tkae it to the shop.

 

[Aussie MacGyver]

Still think the chain and bar are bogus. Engine rips up and down the scale nicely, smooth long idle. I have just put a carb kit through it . If the chain was the wrong guage for the bar (too thin) I would assume it would get hot real quick and would slip in the sprocket. This is what is happening (pretty sure). If I measure the width of the bar groove should that equal the width of the chain drive teeth? Or have I missed something somewhere.

I am hesitant in taking it to a shop because it is a 50 year old saw and looks it. But as I said it runs smooth, I just think the PO has made a booboo with the chain.

 

[Upchuck]

when you tighten the bar after adjusting the chain make sure you lift the tip of the bar all the way up, I lay mine on a piece of wood thats higher than the saw and that takes helps then tighten the bar, also make sure you got no wood chips or other crap between the bar and the saw that may not be letting you tighten it enough

also make sure the chain is getting lots of oil and the holes in the bar aren't plugged with old sawdust

 

[314epw]

too tight?

Is it a new chain?Drive link should fit in bar groove with just a little side play.50 year old saw,how old is the bar?Might need to be replaced.If you tighten the new chain to tight it will stretch fast, so adjustment is necessary.Also if too tight saw will bog down because your using a lot of power just to spin chain.If paint is coming off bar rails,and turning blue your chain is way to tight./B]
Ed:deadhorse:

 

[Aussie MacGyver]

The bar groove looks square (not rounded or anything) but the chain can tilt to 30 degrees or more either way. That's why I thing the chain is wrong for the bar. Bar doesn't get too hot, doesn't smoke or anything. I probably use 1 and a bit tanks of oil per tank of fuel so I think I am using the right amount.

cheers
Scott

 

[l2edneck]

worn out adjuster screw?

causes bar to slide off just enuff to cause slack ive noticed on certain saws more pull on sprocket ultimatley tweakin bar and chain which causes wear on adjustment screw(be sure an to correct me if im wrong)

 

[SawTroll]

The bar groove looks square (not rounded or anything) but the chain can tilt to 30 degrees or more either way. That's why I thing the chain is wrong for the bar. ...

30 degrees are too much, is the saw cutting streight?
My guess is that either the chain is the wrong gauge, or the bar rails are excessively worn.

Are the groove equally wide at the bottom, as on the top?

 

[Ekka]

Problem is that the saw bogs down in a cut and the chains stalls (stops). Lift a bit and the chain will speed up and I can start the cut again. When this happens there is a high pitched rattle and when I rev the saw it feels unbalanced.

This is the part that really worries me. Is the drum split, bearings shot, clutch stuffed etc?

I suggest take the bar and chain off the saw and check that all shoes and springs are on the clutch. Grab the clutch and try to wiggle it and see if the bearing is there and how much wobble there is.

If all looks sound start it up and see if the rattle and vibration is there.

After cutting the chain gets very loose. It will hang well below the bar. I'm sure I am tightening it right.

Now the only way that this can happen is ...
1/ the bar has slid coz the bolts aren't gripping it
2/ the end of the bar has flared open wider and the chain is getting stuck in the groove. Most likely considering that the chain wobbles around in the bar that much. you might have an 050" chain in an 058" bar which would make this a very likely problem.
3/ the sprocket etc are wrong pitch to chain, for example running 3/8 chain on a 325 bar etc
4/ clutch bearing is shot to bits

 

[Aussie MacGyver]

Clutch, springs, bearing are all good. No burn marks, tempered metal, rattle/wobbly bearings. The rattle and unbalanced feel only occurs after the chain has bogged down. If I pull out of the cut and let the saw fast idle for a minute then rev it is all balanced again. Kind of feels like chain is running outside of the bar groove.

After looking at it again I am pretty sure that the chain is too small for the bar. The chain can move a noticable amount left and right in the bar groove. I will pull the bar off and trot on down the shop and get a new chain to suit.

cheers
Scott

 

[Ekka]

And for curiosity sake try different guage chains in the bar to feel the "wobble/snugness".