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The governed ignition unit will then take care of any over speeding.

Certainly low compression will affect the idle greatly, if you think it has low compression then it most probably has., compression test should tell us, or just pull the cylinder off and see what sort of ring end gap we have,

244rx cylinder is from the 444 with closed transfer ports, the 44 had open transfer ports, I guess there is no reason why the cylinder and piston would fit as an assembly, I may have a 244rx engine unit somewhere under a bench.

I would say clean the cylinder up and fit a new piston, I guess there will be some on eBay, the 44 was the semi pro version of the 444, very nice little saw in its day, the early saw was the Practica 44, with a white cover, the later one had an orange top cover, they suffered a bit with the fuel hose splitting as it had a bellows in the centre to allow it to stretch as the fuel tank moved independently to the motor, very difficult to get an ignition unit for it today, the flywheel has two key ways in it depending on which ignition unit it had.

Of all the battery products out there the top handle chainsaw in my opinion is the best / most useable product, with that in mind the T540i is certainly one f the best out there at the moment.

Just a p.s. you loose a 1000 rpm for every additional 1”of cord you pull out.

Brush cutters are very easy to set, fit a trimmer head and extend the cord to the correct length, the engine will now be under full load, so lean the mixture, H screw ,until the engine dies, unscrew the jet until the revs are as high as it they go, now back off 5 minutes on a clock face, it’s now set, usually around 9/10000 rpm

Governed ignition unit set to 12000 rpm, max power achieved at 9000 rpm.

Send me a pm.

Yes, but once apart you would change both bearings.

The screws are not available as a spare part as they are not supposed to be removed, I may have a scrap cylinder to take one from if it helps.

Try this

You will be able to see the bearing cages by removing both crank seals, easier than splitting the crankcase if the bearings look ok.

I think the saw needs to be completely dismantled before you even consider fitting a new cylinder, it’s a mark 1 machine, not sure what you paid for it but this is not going to be a cheap repair, can you return it ? how was it described?

You may well have issues in the bottom of the engine, possibly main bearing cage broken up as there are some groves on the transfer port side of the piston skirt.

What you have there is an ingress of something very abrasive, this has scored the inlet skirt of the piston, and also removed the nikasil coating around the inlet port( as seen by the shaded area around the port ) this now requires a cylinder and piston. where and what have you been cutting?

It realy depends on the age of the saw, however to go through the changes, remove the hose from the breather , this will stop fuel vapour entering the filter elbow, dont forget to blank the the conection on the filter elbow, next if the fuel hose is clipped into the induction manifold remove it and shorten the hose, re connect to the carb ( you will need to turn the the carb inlet connection ) this will take the hose away from the heat of the cylinder, if the saw is a G model remove the the heater pad sandwiched between the carb and the filter housing, open up the cylinder cover on the right hand side ( not in the carb side of the cover or this will stop the centrifugal air cleaning ) remove the the deco valve and fit the blank, get it connected to common service tool and reset the carb settings, if the saw has an orange frame air filter try to obtain a yellow frame filter, the orange framed filter id very very fine and even though looks clean can be blocked, this will cause auto tune to lean off and run too lean, finally pressure test and compression test, any loss of compression will affect the idle. It goes without saying basic maintence should be adheared to, cleaning any clogging in the starter housing grill or between the cylinder fins, never use stale fuel, replace the fuel filter regularly. On rare occasions i have loaded the 555 firmware onto them.

I assume that means it’s going, glad to hear it.

I do hope it just fires up and away it goes, but with a drop of fuel down the inlet, and a spark it really should have at least popped, but please prove me wrong by telling us she is running tomorrow.

Not convinced.

Couple of old farts together I guess.

So it is a clamp shell design, the main bearings are supplied sitting inside a carrier which also incorporates the crank seal, you can buy just the seal and carrier but to try and press the bearing into them is a real pain in the ass, the cylinder is sealed to the crankcase with gasket cement, so machine apart , new bearings with seal and re seal the bottom end, as the crankcase/ oil tank are composite check the area where the bearings sit, if there are signs of melting or distortion you could have bigger issues trying to seal it, there should be no need to put seal ent around the bearing carrier.

As I recall the Zara was the EPA carb from the 365, very difficult to tune due to it being a low emission carb.

Not really a lover of Stihl, however L& S have always been a good source of parts when I have touched the, my experience with those Chinese carbs has been bloody terrible, a good friend on here gave me good advice, and it was always far better to rebuild the original carb, accelerator pump is the first port of call on the carb, sling the Chinese carbs as they will send you round the bend trying to tune them, the roller bearings used on these machines will always give you end float, so quite normal. Over to Spud now.

I think it is a chain saw Steve, it could be a 254, or a 345, or anything I guess, if it is a 345 as you know it’s a clam shell design and the bearings sit inside the seal.