Megatron

Good point about piston damage Spud, the force on the piston increases the higher the piston is in the cylinder for the same crank torque ( I won't go into the phsyics just trust me) so the more rope down the hole the better if its hard to undo the nut, (always turn it the same way it goes around when running).

You want to lock the piston where the crank throw and con rod are at 90 degrees to each other. The position with respect to the top of the cylinder will vary depending on the stroke.

Impact wrench is the best, using only the compression of the engine. Take the flywheel off first to prevent shearing the key.

IMO, it is to support their dealers. How many people go to a dealer with the intention of just buying a saw (or anything else) but come out with PPE equipment, extra chain, bar oil, 2-stroke oil, files etc. If you were to order online chances are you would have just got the saw. There is no way dealers could survive without the footfall through the door. The Stihl policy is worldwide AFAIK.

Husqvarna shafted their dealers when they changed their policy. I believe they are appearing in some of the "big box" stores in the US now, only downhill from there.

The only thing I don't understand about Stihl is national parts availability. Why can't we get 3/4 wrap handles etc

Yes, that's a fair comment, but if you put the big dogs on it then you may as well.

 

Yes the bar fits and I'm pretty sure it works with the chainbrake handle. On the 660 there is a different brake handle for the 3/4 wraps bars.

Yep, no reason to change the 460 brake handle (unless you want to fit the catalytic muffler).

For the 660;

In 2008 the shape of the 3/4 wrap handle bars was changed and they standardised the 1122 790 9101 brake handle so that it would work with the new 3/4 wrap handles.

Hence,

For the newer 3/4 wrap handles 1122 790 3611 (unheated) and 1122 790 3610 (heated) you can use the newer (post 1998) standardised 1122 790 9101 brake handle.

For the older 3/4 wrap handles you have to use the 1122 790 9102 brake handle. Which you also do if you have the full wrap handle.

That old scherader valve on the end of the pipe or by the gauge is a load of:001_rolleyes:

 

The vast majority of gauges have some sort of valve near the gauge but this meerly lets out the air after taking the reading and has no bearing on the pressure read.

 

The critical valve is the one in the bit that screws in to the engine - some have a soft spring schrader valve and these are fine but can read a little low, some have a stronger spring schrader valve and may not even take a reading off a small engine and the others use a brass bullet like valve with an o ring on it - these tend to take a higher reading and are good for smaller engines such as strimmers etc. The compression in the engine has to be strong enough to open the valve and this causes some difference in how they work!

 

All I can say is the guy is using the newer type Gunson using the soft sprung schrader - I have one of these and 150psi is a good reading on this gauge - I have got the same on an engine with a new piston!

 

I don't mean to find fault in others comments but have three types of commpression gauge plus one that didn't work so have compared all and all have their own benefits and have taken note of how each works so speak with much experience.

 

The guys 150psi is fine when measured with this gauge.

There is a type of compression tester that does not have a check valve at the end of the hose. Hence, the volume of the hose is added to the combustion chamber volume.

Compression readings are only good like you say at comparing with another known good saw, measured with the same gauge. As a result of the many variables involved including the opening pressure of the valve etc

Oops, forgot to say check the tank vent first.

Not exactly. The oil pump for these saws is press fitted into the plastic housing instead of screwed to the crankcase and both the pump and oil pick up hose are accessed from underneath the saw instead of from the side on the 036.

Is the leak coming from the sprocket area or from underneath the saw, above the handle?

And then why not the long clutch cover 1122 648 0401 complete with chip deflector 1122 656 1510 too

 

You could be right about the availibility in the UK. I got mine in the US. Pretty sure Mister Solutions sell the DP cover only.

IMO there isn't much point in the longer clutch cover unless you have the 3/4 wrap handle and you can't get the standard wrap handles for the MS460 in this country.

However, you can get the 3/4 wrap handle that fits the MS460 rescue saw, which will fit.

Like already mentioned it is quite possible the ignition or even the impulse hose is collapsing.

Are you sure there aren't any adjustment screws?

It is possible to richen the saw up by bending the inlet control lever slighlty up (or drilling the jets ever so slighlty bigger on a fixed jet carb).

With regards to the piston, the MS640 and MS650 pistons don't have the same Stihl part number which usually means they aren't compatible. However, since the MS650 is the successor to the MS640 it is possible the pistons are in fact compatible with the MS650 piston part number being more up to date. Unless you find out for certain then I would recommend;

Contact STIHL – The Number One Selling Brand of Chain Saws | STIHL

Select technical question. Don't mention the word "aftermarket" and you will have to make up a US zip code.

So it looks like the conrod seized instead of the piston. That black dust will most certainly have been a contributary factor. What air filter did the saw have, the wire mesh one?

To rebuild you will need a way of extracting the crank out of the case without causing damage to the cases. The Stihl tools are £££, if you can weld you can relatively easily make your own tool to push the crank out of the clutch side case. Then you can either use a press or big clamp to push the crank out of the flywheel side or again you can make your own tool. (I wouldn't recommend using a mallet to extract the crank out of either side).

If the bearings stay in the case you can push them out with sockets and a big vice and if they stay on the crank then use a bearing splitter or jaw puller etc You can reinstall the new crank and bearings into the case using heat...

Do you have a spur or rim sprocket set up at the moment?

I am not aware that there is a 0.325" spur sprocket that will fit. You can however get a 9 tooth rim sprocket. You can get higher teeth numbers but you would probably have to get it from a saw racing specialist.

The 066 uses the standard 7 spline like many of Stihl's saws. The part numbers for the rim only (9T 0.325") (no clutch drum);

Stihl 0000 642 1239

Oregon 13624

I wouldn't have thought the strength of the chain would be a problem. Chip clearance might possibly be an issue but with only 20" you will probably be OK.

I'm fairly sure its not been made in Germany

What gives you that idea?

Like a lot Chinese produced cheap saws it is the YD-52 type;

YD52 chainsaw products, buy YD52 chainsaw products from alibaba.com

or just google (images) "yd52 chainsaw"

The AU/NZ saw have a bigger port in the casing as well as the dual port cover, but the cover it worth fitting. MS440/460 Dual port part number is 1128 140 0801

 

The large felling dawgs for a 460 are:

 

Inner: 1122 664 0506

Outer: 1128 664 0501

If you get the dual spikes you should get the roller chain catcher,

part number 1122 650 7700. Then remove the stock one.

1128 140 0616 is the AU/NZ full exhaust (casing with cover).

 

There's also 1128 140 0612 which I think is the same, but with out the spark screen.

I am pretty sure you can't get those parts in the UK as they are meant for other markets. You can get the dual port cover though.

I fitted the large dogs to my 460 and smaller twin dogs on the other 3/8" chain saws - only really used for stump cutting but handy to have.

 

For carb adjustment with the Duel port cover is it just the hi & lo air screws or does it require different jets to be fitted, don't want to risk damaging the motor.

 

Plus any details on power increase for a 460 ?

 

many thanks:thumbup1:

You shouldn't need a bigger semi-fixed jet or bigger carb when just installing the dual port cover. The H, L and Idle screws will need adjusting though and depending what carb the limiter caps will need to be removed for this. Don't install the dual port cover if you are still under warranty, wait until it runs out.

Power increase would likely be about 0.5hp.

IMO you want to be looking for 140+ psi on a chainsaw. Anything less there is usually a problem. 150 should be fine but if you have reason to believe your piston and cylinder are deteriorating then pull the muffler to check. Compression doesn't tell the whole story... the saw in the picture was pulling 170psi.

The rate at which you turn the engine over (within reason) shouldn't influence the compression reading. There is no need to peg the throttle open either as the saw will just draw air through the exhaust port instead of the intake. Just keep pulling the rope until the compression reading won't go any higher.

I believe there are two types of compression gauge. Those that have the schrader valve at the end of the hose (what you want for testing saws) and those that have the schrader valve next to the gauge. Using the latter would mean the volume of air in the hose would count as part of your combustion chamber volume and you would consistently get lower than expected readings. Wouldn't make that much of a difference with a car engine cylinder, with a much larger combustion chamber volume.

I have a second hand pull cord for the 880 if that's the same?

088, MS880 before 2009 and the post 2009 updated MS880 all share the same recoil.

I think the "standard" (recommended) for the 066/MS660 is 8T and 7T for 064/MS640/MS650...

(3/8ths, of course)

Latest project - one of those Stihl 020AVs - the predecessor of the 020T and MS200T. The saw has been used for the rough stuff for a while and I extricated half a hedge from around the sprocket - lucky there wasn't a mouse in there as well!

 

Looked for the carb but could only find a brown turd like extrication hanging off the side of the cylinder:001_rolleyes:

 

Cleaning up well though - stripped the carb, noticed that the needle valve was a bit sluggish and not sealing well - the last picture shows the reason - the plating has started to bubble off the needle - the replacement is next to it.

 

Only parts I have found to need replacing are the sprocket, lower handle AV mount - sorry "annular buffer" - gotta love the Germans:001_rolleyes: The chain is a gonner and the handle needs a bit of epoxy as it is cracked - compression is a healthy 160psi.

Parts for these saws are getting scarce as they are being phased out by Stihl. I have listed a few examples below, the column headed "year" denotes the last year in which the part was/will be available from the factory. However, this doesn't necessarily mean you can still get the parts up until that date, it differs from country to country. But unless your distributor still has some in stock, beyond the date, you are out of luck...

Think you saw my earlier posting - the 026 isn't the one with the busted tank - pleased with the result though and am sure the owner will be - don't like to let everyone know whose saws they are unless they are happy to pass comment!

Didn't pay much attention to the pic, just followed on after you were talking about the 026

I see the motivation in trying to mend the tank now seeing as it is off an MS880 (or MS780). £80 excl VAT is quite cheap by MS880 standards though. (I'm assuming it is pre 2009 model, if newer then £105 excl VAT)

I'm assuming you mean the MS 441 C-M ?

(A model with C-E means it has ErgoStart/Easy2Start)

Without getting into to much detail; The MS441 C-M has a fully electronic M-Tronic engine management system. When working correctly it regulates the ignition timing and electronically adjusts the fuel flow, taking external conditions into account.

The dealer is right in some respects. Stihl are supposed to be making software based diagnostic equipment for the M-Tronic saws but it hasn't been released yet. (Husky are no better with Autotune). It isn't tuning equipment though rather diagnostic equipment.

However, until then he should be able to test with a multimeter in conjunction with the M-Tronic test lead, part number 5910 840 0903. There are "target values" in the Tech Bulletins for the Solenoid Valve, Micro Switch, Wiring Harness etc. He may have been doing this though... did he try swapping components for known good ones?

The tank isn't off a 026 otherwise I would have taken a second user one and used this, it is now repaired and happy it is probably stronger then the original with everything lining up.

024 and 026 saws of the same age share the same tank...

Latest kit to hit the bench - the 026 has been cleaned and the new piston fitted - compression is 170psi + and sounds good, no noise from the crank bearings and will see in time if it is a good job but all looks good.

Got a repair to a handle moulding - owner didn't notice it had broken, expensive part so I am patching it and have made the metalwork to do so.

Another project - a two stroke drill....no I haven't seen one before either, symptoms are inabillity to rev - owner thought carb but a quick tune and removing the air filter briefly made no difference - I reckon it has a blockage in the exhaust - perhaps carbon in the baffle plate but will see!

You can get a good used 024/026 tank off ebay for £24.50 not including delivery. You would have to modify the tank vent and more than likely get a different fuel hose though as it is from an earlier version.

The two stroke drill looks to be a BT 45. Shares exactly the same engine as equipment from many of Stihl's ranges including; BG, FC, FS, HL, HS and others.

Pretty sure it has a spark arresting screen which can clog, both UK and US versions. Also similar to the MS200T (and many other models) it has an accelerator pump on the carb...

Well spotted:thumbup: the saw is pretty old, in an ideal world you are spot on and fitting these parts is good advice but the saw is old and has some sentimental value and like always, am trying to meet customer expectations on cost whilst doing a repair up to a good standard. Don't think a £400 repair bill would cut it!

 

All I have done so far is to take the pot off, clean and inspect it, a decent clean with petrol and a spin of the crank with the coil off will show up if the bearings are a bit slack and have play - will do this before buying the piston but hopefully, if I clean it out, the saw will have an extended life without heavy cost.

 

A cheap way to sort the flywheel is to take metal of the opposite side of the flywheel - perhaps not in the book but should even up any imbalances! I haven't even taken the cover off yet, better have a closer look before I splash out any expense - may find other horror stories:thumbdown:

I can see what you mean about the cost. Realistically you would be looking at about £100 incl VAT for the parts I mentioned above. New OEM parts except aftermarket piston and good used flywheel.

I think it is next to impossible to balance a flywheel by removing material from the other side... they tend to not be symmetrical. You could probably get quite close but at 8000+rpm, the flywheel side bearing isn't going to thank you.

Picture of bearing with cracked polymer cage, spins freely;

(note; some bearings are installed with the cage inwards, others outwards)

A saw is tuned/jetted mainly for operation at idle and full throttle. Letting a saw warm up on idle should be fine, in cold weather if you don't warm a saw up you can cold seize it. The piston heats up and expands faster than the cylinder. Warming a saw up on part throttle is not a good idea in my opinion as depending on the model carb and the exact throttle plate angle, this can cause the saw to run lean.

I am aware that "modern" saws are tuned leaner (at idle and full throttle) but it should still idle without starving the saw of fuel and oil. If you are milling a long hardwood log it is common place in my experience to stop periodically to allow the saw to return to idle and cool.

As a general rule the ignitions on chainsaws don't like heat! Keep the holes in the recoil housing, the flywheel fins and around the ignition module free from crud. (and the cylinder fins, to keep the cylinder cool)

I know what you mean but the saw had been seized and someone had fitted a new piston without cleaning the bore, the grey sludge is a mixture of petrol, aluminium that the new rings have worn from the bore and a little WD40 I put in the bore as the saw was dry and I wanted to measure the compression.

Bit of a mess but probably looks worse than it really is - will take a judgement on the bearings but there is no play and the crank bearings spin freely even without cleaning.

 

One thing - a new flywheel:confused1:what is your thinking on this?

My main worry with the crank bearings is although they may spin freely the polymer cages may have been damaged. More so with the acid theory though.

The flywheel appears to be missing at least one fin...

Todays project - 026, low on compression, a glance down the plug hole, the bore looked quite clean -

 

Took the exhaust off and the piston is badly scored, stripped the top end out and wow - what a load of grey sludge is on all the parts.

 

Someone had rebuilt this saw and it never ran well afterwards - this was before I got it.

 

The bore looks like it has cleaned itself as I got very little aluminium off it, the pic is the bore before cleaning.

 

A new piston will get it going, the crankcase needs flushing out - fortunately the aluminium is soft and fine and the bearings feel sound but will retest after cleaningl:thumbup:

It looks like someone tipped acid or the like in the plug hole to try to unseize it. Can't imagine where else the grey precipitate could come from?

IMO needs at least a new piston, bearings, seals, gaskets, carb kit, hoses and flywheel... If you want a saw you can rely on.