Husky 560xp mk1. Vibration when in the cut.......?

[medroberts]

Guys, Whilst using my husky 560 yesterday on firewood, I noticed a strange vibration whilst cutting .I have owned the saw from new and have only ever used husky synthetic 2 stroke oil in it. Saw will start and run fine. I have removed the bar and cannot see any obvious reason for this issue. I can see that these suffer from failure of the crankshaft bearings nylon races..... Could this possibly be the cause of the vibration ? I can see a pressure test of the crankcase could reveal the crank seals leaking , and thus bearing failure ? Unfortunately I don't have a hand pressure/vacuum pump. A question to Spud (Steve), could you carry out this test for me of the crank bearings ? If I send you over the saw ?  Ps The 395xp you ported for me is still going strong .....   

Regards, Med Roberts

[adw]

Normally if the bearing cage has broken up the seals are damaged, this in turn makes the idle very erratic along with vibration, very often you can see traces of melted material in the spark arrestor gauze, there are other things to create vibrations, clutch damage, sprocket damage/wear.

[medroberts]

Hi ADW, Thanks for your reply. I have fitted a new drive sprocket not that long ago. I haven't run the saw after noticing this vibration, for fear of causing more damage. But seemed to start and idle correctly. I only noticed the vibration whilst under load i.e in the cut. I have looked at the clutch and all return springs are intact ( never had to replace any since new !) Would I be able to feel play in the crank bearings if the races had failed ? If I were to take off the clutch and check for axial play ? I will take a look in the spark arrestor gauze as you suggest, Rgds, Med  

[adw]

I know it sounds unlikely but you will not see play on the crank if the cages have gone because all the balls are still there, you do get vibration because the balls are no longer correctly spaced, you could bite the bullet and pull the seals out, you will then see the cages, they are easy enough to to remove ( they are within the bearing) however great care, and ideally special tools to replace them, both seals are the same on the later 560 but different on the early saw.

[spudulike]

Glad the 395 is still bopping along nicely. On the 560, ADW is probably on the money on this one. 

[medroberts]

Guys, Finally got the saw to bits and as you can see from the attachments the crankshaft bearing races are intact on both sides.  The crankshaft rotates smoothly. I have also removed the  exhaust and inspected both piston/ring and cylinder. I can see no issues in there either.  The drive clutch and needle support bearing are in good order also. The sugihara bar sprocket tip is free to rotate. Not sure why I am getting this vibration in the cut ? The deflector limiter bush is worn and I will replace when I order parts to rebuild. But I cannot reason why this would cause the saw to have a vibration whilst cutting.... Your thoughts please...

Thanks in advance for the assistance

[Haironyourchest]

Are you sure it's not your chain? Missing a tooth or something?

[medroberts]

Hi Haironyourchest, That was my very first thought. And although the chain is 50 % down there is no teeth missing. Regards, Med

[adw]

Can’t remember the last time I saw one that clean, so with that out of the way, do we have contact between the crankcase and the fuel tank? or is there something trapped between crankcase and tank? 

[medroberts]

Hi Adw, I have cleaned the saw before stripping it down. I am an agricultural engineer by trade so I know how important cleanliness is . Thankyou for your further thoughts . I will check this out and update.

Regards, Med