What's on your bench today?

[the village idiot]

Had an unusual one with my 346xp today. Last week my bar nose sprocket gave up the fight. I replaced the bar, but for the next couple of days the chain wouldn't run smoothly, it would snag when manually pulling the chain around the bar and the saw was finding it hard going and running very hot.

I checked the chain, bar and drive sproket, everything seemed fine but when the saw was assembled it would start to snag again.

It was not until I had a really close look at the drive sprocket that I noticed one of the bearings from the disintegrated nose sprocket had ended up perfectly wedged into the middle of one of the recesses of the drive sprocket. This raised the chain slightly, once each revolution, throwing it out of line and causing it to snag as it entered the bar.

The bearing was a right bugger to get out. The chain must have carried it to the drive sprocket and deposited it with micro-millimetre precision.

Anyone else had this happen?

[spudulike]

Had a 3120XP, 346XP and MS150T in today, the MS150t was "making a funny noise", first thing I noticed was that the on/off switch wasn't working and traced it back to the fact both engine mount bolts had failed, one of which was the earthing point - one had sheared and one thread had expired.

 

I helocoiled both and also fixed the lanyard attachemnt clip with something a lot stronger:thumbup:

 

The 346XP was a non runner but started for me, 150psi - I did notice the clutch spring was fractured and the rim drive was worn so replaced both springs and a new rim.

[MATTMOSS]

There are bolts that hold a cast ally shroud around the flywheel, these often come loose and sound terminal! - it is the casting the recoil cover bolts to!

 

Blower stripped down to the last bolt now.

Its got me a bit puzzled? all looks in good condition and no play in bearings, seals seem tight but ill test when rebuilt.

Only thing is the build up of carbon in the exhaust and the crown of the piston.

Going to give it all a thorough clean up with new rings - cos I broke one and see if its any better.

I wonder if it was a large piece of carbon rattling round in the exhaust? going to have to retune the carb its obviously been running too rich or the owner has been putting too much oil in the mix.

[spudulike]

Blower stripped down to the last bolt now.

Its got me a bit puzzled? all looks in good condition and no play in bearings, seals seem tight but ill test when rebuilt.

Only thing is the build up of carbon in the exhaust and the crown of the piston.

Going to give it all a thorough clean up with new rings - cos I broke one and see if its any better.

I wonder if it was a large piece of carbon rattling round in the exhaust? going to have to retune the carb its obviously been running too rich or the owner has been putting too much oil in the mix.

 

It could be that the carbon is closing the gap between the piston crown and the squish band - had a 390XP with this recently! I usually scrape the squishband with a sharp wood chisel - a few engine builders are known to do the same:thumbup:

[MATTMOSS]

It could be that the carbon is closing the gap between the piston crown and the squish band - had a 390XP with this recently! I usually scrape the squishband with a sharp wood chisel - a few engine builders are known to do the same:thumbup:

 

Yes I reckon you're right.

[jamesd]

Got a clutch bearing to do on a Stihl FS100 long handle hedge cutter. Got everything apart ok but trying to figure out the best way to get the bearing out! It seems a tight fit in the plastic case. Does anyone know the best way to get it out without hurting the casing?

 

Cheers!

[Ray1]

Pressing it out is the only way ive ever done it and never damaged the plastic shroud, there is a cir clip holding the drum in place if you look down where the shaft goes, this needs to come out and can be a fiddle. Ive never done one where the drum comes out first then have to press the bearing out second, always come out together. If yours happens to do the same there may be a big flat headed screw holding the bearing in place (cant remember if there is one on the 100 some use a big cir clip which is easier) this needs to be undone as you press the assembly out.

[jamesd]

Pressing it out is the only way ive ever done it and never damaged the plastic shroud, there is a cir clip holding the drum in place if you look down where the shaft goes, this needs to come out and can be a fiddle. Ive never done one where the drum comes out first then have to press the bearing out second, always come out together. If yours happens to do the same there may be a big flat headed screw holding the bearing in place (cant remember if there is one on the 100 some use a big cir clip which is easier) this needs to be undone as you press the assembly out.

 

Ok thanks. The bearing was in a pretty bad way so the clutch drum fell of without having to remove the circlip at the end of the shaft. (I take it its that small circlip you mean).

How do you go about pressing the old bearing out then? do you have to remove the metal sleeve and antivibe rubbers to get better access?

And yes mine has got a screw which holds the bearing in place. I think the one which has a big circlip holding the bearing in has a different bearing part number, which is where i got confused.

[Ray1]

I remove the sleeve and rubber as its the only way to give you room to get at the small cir clip. I use a press, sit the plastic shroud on 2 pieces of wood so its flat and press the bearing out using a long socket.

[jamesd]

I remove the sleeve and rubber as its the only way to give you room to get at the small cir clip. I use a press, sit the plastic shroud on 2 pieces of wood so its flat and press the bearing out using a long socket.

 

Ok cheers, how do you get the rubber and sleeve out? mine seems pretty well in there, don't want to damage them!