spudulike

Usually poor piston to bore clearance and greater squish. Usually just a poor piston to bore fit lowers it significantly. The compression is unaffected by the transfers and the only port to effect it is the height of the exhaust port as compression is made as the piston clears the top of the exhaust port and heads up to TDC.

Apt for this day......

I remember Madame Cholet and Uncle Bulgaria, not sure I remember Cock Womble??? As for Chris Packham, I quite like the bloke for being passionate and battling his demon Asperger's. Rather share a pint with him than one of these polished celebs up their own posterior!

Poor compression......... scores in the bore, scores on the rings, scores on the piston, worn piston skirts, worn bore, worn rings, holed or cracked piston crown, saw has nipped piston, broken ring, poor cylinder/piston manufacture, too much squish clearance, saw not run in well, carbon build up causing stuck ring.....I am sure there may be more!

I have enough crap saws rolling in without numpty Facebook and Twitter ijuts sending their crap in as well and I also have no interest in what my friends are eating drinking or fooking - I invite them round for a drink and curry - it may catch on!

Good saw the 395XP, nice to work on

Pretty decent saw, they have their issues but are about as good as they get. Lots can be done with them and makes them absolutely bonkers. Good AV and nice handling saw.

Reckon you got your moneys worth out of that repair and porting, nice to see it hasn't shortened its life. I think we have seen the last of the saws that will easily last 5-10 years.

Nice to see the 395 is still working well, that must have been 4 years ago now!

Damn, you said you wouldn't tell! I did get strange looks wearing a business suit and carrying chainsaws though

Does it involve meeting up in a layby at dusk

I wasn't having a pop so apologies if it looked that way. I once wasted many hours on a 039 carb spraying it and getting nowhere but it can help especially on the clutch side seal if it is leaking.

And that is....bearing lock D'oh Use Loctite 270 - that will stick em in for life but de-grease first for maximum grip!

Stick a 13" on it and fill ya boots

As others have said, taking kit apart and putting it back together is a good start. The thing you have to do is question every part for its fit, form and function, analyse everything as without that, you have just got a meccano set! I have no formal training but the overwhelming NEED and WANT to fix kit and learn more and more has done me well and fixing my own bikes, cars, machines in previous employment and a broad knowledge of everything computers/mechanics/diy etc has helped

It isn't what the machine is rated at, it is what the oil manufacturer recommends so if you have a vintage machine, the oils of the day were 25:1 but if you use modern synthetic Stihl in it you would mix it at 50:1 Some no brand oils may state 40:1 but most decent modern oils are 50:1.

If I burn Oak I try to mix it with a faster burning wood. Got a bit of Oak and cedar at the moment and works for me.

Why are you lot bothering over this? We have two diverse views and neither are ever going to see the others and be converted! Both arguments may have some reasonable points in their arguments but neither will concede. Views like this are swayed by peoples age, what they have experienced in life, how travelled they are and on their friends and acquaintances etc, I am guessing Matelot has seen a few more years than some of the other posters on this thread! There will never be resolution on this one so why carry on, you may as well argue about religion!

Spraying carb cleaner around the manifold condenses the fuel and causes the machines idle to change even on a healthy machine. This is down to the carb cleaned taking heat away from the manifold to evaporate the solvent and basically turns the vapour back to fluid! Better to roll some light oil around the areas. OEM cylinder - good, aftermarket carb....can be good or bad. I have seen these on MS200s and have had to modify the throttle valve to get them to work anything like the standard unit and was pretty poor TBH. Personally I would either rebuild the original carb or purchase a new/second user OEM one and try that. A bad air leak will cause the saw to rev out but not idle well. Try moving the L screw out 3-4 turns and if you then get some sort of idle then it is probably a bad leak but if it does nothing, you most likely have a carb issue, Making the L screw super rich sort of counteracts the air leak but is NOT a solution, just a diagnostic tool! After doing this sort of thing a bit, the machines sort of tell you what is going on through their behaviour!

What sort of Loctite are you using?

You would usually set the new carb to one turn out on the H & L screws, set the idle screw so you can see a bit of daylight around the throttle valve plate and then fire it up and just make the slight adjustments needed to the H,L and idle screw. If the carb is the correct part then it should really be a simple job and if the top end is either OEM or a quality aftermarket part, then all should be good. If you have used the cheapest top end then expect around 140psi and it to be a bitch to start hot. If you have used an aftermarket carb then expect anything between the set up being as OEM new to being like pissing in a force 10! You spends your money and takes the chance.

Beats using those smelly noisy chainsaws and looks very safe

I once had a 346 in with three cylinders, all shot. The owner had put on new cylinder after new cylinder and trashing them without realising the big end was on the way out and spitting out random bits of bearing cage. I got there in a short time and stopped the repeated waste of money and there is the lesson! As others have said, you will need to pressure/vacuum check the saw and make sure the saw carb is tuned correctly. you could just change all the seals and lines but I have seen a certain MS660 that had fractures to the crankcase causing air leaks. I did manage to seal it and port it and it is still running 3 years later so sometimes not actually doing the test can miss issues. A lot of these aftermarket kits are a bit iffy and tend to have poor compression and this will lead to a boggy saw....I would personally always use OEM or Meteor.

That's a good price!

My trainer choice is a summer one - if the ground is generally good and it hasn't been raining then they are comfortable and lighter than boots. I wouldn't be wearing them in the middle of winter on rutted muddy ground but would on the costal walks we do in the summer!