Stihl MS660 nasty vibration

kjudd · Feb 28, 2018

Moparmyway said:
A busted spring
A cracked shoe
The oiler arm not being in the slot on the drum
Etc ......

All cause vibrations

The saw ran smooth before the cross top end. I took a huztl big bore top end off to put the cross on. Because my base gasket deleted Huztl 660 would out mill the big bore saw. So figured I would try the cross top end on it to see if the 2 would cut roughly the same.

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MustangMike · Feb 28, 2018

Make sure the flywheel was not hitting the cylinder, they usually (the Cross cylinder) have to be filed.

Also, I'm not sure why, but one of mine needed spacers on the lower muffler bolts, but not doing that should not cause vibration.

Wonkydonkey · Feb 28, 2018

If you Put it back how it was, if there's no bad vibes, ?

kjudd · Feb 28, 2018

Wonkydonkey said:
If you Put it back how it was, if there's no bad vibes, ?

Didn't start it. I was giving the 1184 time to cure before starting it

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Wonkydonkey · Mar 1, 2018

kjudd said:
The saw ran smooth before the cross top end. I took a huztl big bore top end off to put the cross on. Because my base gasket deleted Huztl 660 would out mill the big bore saw. So figured I would try the cross top end on it to see if the 2 would cut roughly the same.

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This was what I was ref: to. If it works fine with the big bore hutzel, now it vibes like a sob.. With the cross. Put it back to how it was.. Then, it's a process of elimination as to the vibes.

But as with all things China-style, some work good and some are crap.

Btw. A few have said (many builders) std cylinders work better than a big bore kits, as you have better case compression. Also the cross is/should be better than a std hutzel cylinder.?

kjudd · Mar 1, 2018

Wonkydonkey said:
This was what I was ref: to. If it works fine with the big bore hutzel, now it vibes like a sob.. With the cross. Put it back to how it was.. Then, it's a process of elimination as to the vibes.

But as with all things China-style, some work good and some are crap.

Btw. A few have said (many builders) std cylinders work better than a big bore kits, as you have better case compression. Also the cross is/should be better than a std hutzel cylinder.?

I'm hoping to fire it up in the next few days to see if the bearing swap fixed the problem. Then I will go from there.

The huztl saw is a base gasket delete with minor port job on it. Basically a smoothing of transitions and widening of the ports. and gasket matching the muffler with a muffler mod.

Redfin · Mar 1, 2018

Did you take a real good look at the crank while you were in there?

kjudd · Mar 1, 2018

Redfin said:
Did you take a real good look at the crank while you were in there?

Yes. No marks on either crank or piston. Also made sure to pay very close attention at bdc for any binding/hitting feel.

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MustangMike · Mar 1, 2018

The Cross cylinders will also usually out perform most OEM cylinders unless they have been ported.

kjudd · Mar 8, 2018

I swapped out the wrist pin bearing. That appears to be the problem. The saw is alot smoother now. Thank you everyone for the suggestions. I still need to check the clutch.

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Moparmyway · Mar 8, 2018

Pictures of the old wristpin ?

MustangMike · Mar 9, 2018

And bearing ...

Moparmyway · Mar 9, 2018

MustangMike said:
And bearing ...

He said that he swapped out the pin

Nothing about the bearing

kjudd · Mar 9, 2018

Sorry i ment wrist pin bearing. Wrist pin looked fine.

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Wonkydonkey · Mar 9, 2018

Was it loose/warn etc and I’m guessing am

kjudd · Mar 18, 2018

Here is the wrist pin bearing I took out.

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kjudd · Mar 18, 2018

I took the clutch drum off and everything looked normal. No cracks or broken parts.

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r7000 · Jun 28, 2018

kjudd said:
I just finished putting a cross top end on my 660...

did you ever figure out the cause?

by "top end" does that mean just a cylinder? or cylinder and also new piston+rings?

MustangMike · Jun 28, 2018

Often AM pistons and pins are heavier than OEM, and will result in increased vibration, ditto all Big Bore Kits.

Also, if your AM piston pin begins to fail, you will also notice increased vibration. Don't ask how I know, but for $10 I now use OEM wrist pin bearings.

Luckily, I felt it, and tore it down before damage was done.

kjudd · Jun 29, 2018

r7000 said:
did you ever figure out the cause?

by "top end" does that mean just a cylinder? or cylinder and also new piston+rings?

I changed the bearing the piston rides on. Smoothed it right out.

Yes I put a the whole cross top end in ( ie the piston, cylinder, rings. ) with no base gasket.

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Stihl MS660 nasty vibration

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Meh...

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Its just a saw

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Its just a saw

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