spudulike

I would scrape the port with a craft knife and use a little emery paper around the bevel of the port to make sure it is smooth. A dremmel with a carbide burr does it pretty well also! The plug hole - just use a little penetrating oil and screw the plug in an out a few times and then clean with paper cloth. If you have a plug hole chaser, this will do it! Piston wear - usually the ring ends become thinner and the piston skirts wear to the point you get piston slap. If you put the non ringed piston in the bore and wobble the skirts back and forth, it becomes pretty obviouse if there is wear. A set of vernier callipers will also help tell you if there is wear, just measure the lower skirt and compare to the top of the piston both across the bore and inline with it.

Just take a sharp craft knife, put the bolts through the gasket and cylinder to hold it in place and cut in to the gasket around those transfer ports to open them up. It would work as it is but would reduce the velocity of fuel/air through the transfers.

Well done, glad it worked out OK:thumbup:

Oh dear:thumbdown:

If it has had a new needle bearing then it may need a new clutch drum as the central bore may have opened up a bit, if this is new then perhaps the crank is worn - less likely on a realtively new saw! It may be that the brake band isn't seated properly so check that also. Does the chain spin on idle or at least make a ringing noise on idle?

When the saw is on idle, it produces very little power. The stalling is caused by the resistance between the crankshaft and the locked up clutch drum. Generally it means that there is dirt on the clutch drum, the clutch springs have gone, there is twine wrapped around the crankshaft or the bearing isn't lubricated etc. The stalling will mean that something is causing resistance between the locked up clutch drum and the crankshaft, just have to find out what!

He's a nice fella:thumbup:

Try this if your imagination isn't up to much....

The saw needs to oil only when the saw is cutting, the saw only cuts when the clutch drum is spinning. The oiler arm links the clutch drum to the gear that drives the oiler. Imagine the circlip you have with a 4cm strip of metal protruding from that short stubby bit that yours has left on it and imagine it mounted on a nylon worm drive, there..... Fit a new one:thumbup:

Sounds like a fair deal:thumbup:

Sounds like the throttle may be stuck open or you have one big air leak - possibly the impulse line has come off or the inlet manifold has split. It is also possible that the throttle valve plate has come loose and is jamming open. I think I would remove the carb and give it a good inspection, make sure the throttle valve is shutting fully and not loose, make sure the linkages are not holding the throttle open, make sure the impulse line is still connected to the bottom of the airbox and the inlet manifold is not split. Reassemble and try again. If it is still racing then I would pressure and vacuum test. If you get stuck, PM me

That looks very much like the oiler arm that is usually clipped round the oiler worm drive pinion, it looks like the arm has worn off due to sheer wear in the needle bearing. Common for the end to wear off but less common to lose the whole arm. Fit a new pinion worm drive and oiler arm as one unit.

Just come back to you.....MS200s.......I believe many have been happy with my work on their saws and how they have worked after their return. Not an issue looking at them, have PMed you a response:thumbup:

Thanks, much appreciated and glad I was able to diagnose the issue and get it back to good working condition PDQ for you Cheers

Mmmm, bit like having a breather with no breather hole:001_rolleyes:

Highly unlikely unless the gasket has broken up and mashed the piston. On the pressure and vac tests - the inlet manifold should be left in place as you are testing this component and its abillity to seal.

Easy, I use a very expensive set of American made plumbers grips, they are perfect as one jaw protrudes a little past the other and gives a slight sliding action as they are closed meshing the locking mechanism together:thumbup:

If the saw is lacking in power then it really isn't a case of adding tuning parts. The first thing to do is to ensure the saw is working well before tuning work is done. What I am saying is the tuning should give power BEYOND normal power and NO make up for a poor running saw. 3 hrs old - try handing it back to the dealer, if out of warranty, check the fuel system - possible sawdust in the internal gauze filter. It is possible the piston has nipped up or perhaps the carb needs a tune up. 3hrs isn't long, it may just need time to bed down a bit before top power is made. Dual port - nice way to go but get the saw working right first....that is unless your expectations of the saw are too high. Oh - I have never seen a standard exhaust with a spark arrestor???

Or the age of the mix, the 346XP does rev pretty high and the oil in the fuel mix degrades over time.....damn, someone will mention Aspen soon:001_rolleyes: If the mix was over a month old and possibly a bit light on oil.....it could have been enough.

Yes, the pressure check is about pumping up the crankcase up to around 10psi and then watching the gauge for any drop but guess you could do without the gauge and use soapy water around all the joints and crank seals - easier with a gauge but possible without. You block the impulse, the inlet manifold and exhaust and input air in through the plug hole. I can look at it if you like - PM me if needed.

Just open up the exhaust, not worth doing any porting on it TBH!

These saws are notoriously bad for leaking around the inlet manifold, the older the manifold, the worse they are. I have also had them leak and then just rotating the manifold round 0.5mm seals it up for good. The small crack around the impulse moulding on the manifold is also pretty common as is not getting the alignment right and squashing the thing on reassembly! I know this from experience and pressure/Vac check all saws on reassembly so the top end isn't taken out like you have just done. The clutch side seal is also prone to failure and can leak. Pressure & Vac testing, you really need the right kit and that will cost £50-75, it may be better to hand it to someone with the right kit and get them to check it over. Hopefully the bore is OK and with a new piston and a little TLC...... Each saw has it's own set of strengths, weaknesses and little things that they need to get them 100%, the 346XP was a fine replacement for the 254XP and is a great performer but like most saws that seize, a rout cause has to be found before running up again! Was the fuel line OK, this can cause this type of issue?

Its a done deal, just got to extricate it from the saw.....Sunday nights, bah, a rest is for whimps:001_rolleyes:

From what I see, I believe everyone wants a new MS200 with a little more power........Ah, a ported MS200, thats the thing every one wants:thumbup:

If you can't find a gasket, buy a sheet of 0.5mm gasket paper and make one, been there before, it is dooable!