MS 460 advice

[pleasant]

11 hours ago, StephenMews said:

Thank you. I shall get some pictures. It will be a couple of weeks until I start on it as I need to borrow a saw first to keep me going whilst fix this one.

 

To make sure I understand. The Bore and cylinder are not the same thing is that correct?

Just a footnote to my earlier comment. Remember, that if you think you can get away with just a piston and then find out your cylinder isnt any good, you cannot buy a cylinder on its own...they come as a pair, so you will end up with two pistons, one of which will be surplus and wasted money.

[Ledburyjosh]

56 minutes ago, pleasant said:

Just a footnote to my earlier comment. Remember, that if you think you can get away with just a piston and then find out your cylinder isnt any good, you cannot buy a cylinder on its own...they come as a pair, so you will end up with two pistons, one of which will be surplus and wasted money.

OK thanks.

 

Sounds like replacing both is the way to go.

 

Whilst I am at it is it worth replacing the carb also?

 

I had a look at piston and cylinder kits, and noticed I could put a 54mm one on rather than the 52mm for a bit more power.

Would other parts need replacing for this to be compatible?

[Ledburyjosh]

HYWAY STIHL 046 MS460 54 MM BIG BORE CYLINDER KIT NISIC 12 MONTH WARRANTY

WWW.SAWBITS.CO.UK

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Hyway compatible Stihl 046 ms460 cylinder kit new 54mm big bore comprising of cylinder piston piston rings gudgeon...

 

 

 

[pleasant]

43 minutes ago, StephenMews said:

OK thanks.

 

Sounds like replacing both is the way to go.

 

Whilst I am at it is it worth replacing the carb also?

 

I had a look at piston and cylinder kits, and noticed I could put a 54mm one on rather than the 52mm for a bit more power.

Would other parts need replacing for this to be compatible?

 

[pleasant]

Being a dealer, I have no experience in 'modding' machinery beyond stock, so I won't advise as to whether adding a big bore kit or what is involved in doing so is a good thing.

 

Personally, if you have decided your issues are primarily piston and cylinder, then get those on order. You need to ascertain why there is scoring etc in the first place, as simply re-fitting new parts without finding the cause will simply mean the same issues arising again. I wouldn't aoutomatically replace the carb.....I would definitely try and keep the original one....just re-build it. There are a lot of rubbish carbs out there which can cause other issues once fitted....unless you bite the bullet and get a genuine stihl one for around £90. But, again a new carb and pot and piston won't cure an issue such as leaking crank seals, which could be the original issue...amongst others.

[Ledburyjosh]

Some pictures of the piston and cylinder.

 

[Ledburyjosh]

I've looked through the spark plug hole as well. There doesn't seem to be anything of concern on the cylinder. 

 

The piston does have something going on around the top of it. Not to sure mind.

[spudulike]

That piston looks pretty good to me. The bottom is a bit polished but that does happen, the middle pic shows some original machining marks on the right hand side of the port so it again looks OK and the rings are free in their piston grooves.

I would say it looks like something else is going down here.

Mark Skylands suggestion is a good one as I have also found that the MS460 does tend to draw in fine sawdust and dump it behind the metering diaphragm so worth doing as he suggested.

As far as replacing the carb....don't, just clean it out, check the diaphragms, possibly change them and then retune. 

From what I have seen, I would say the piston is probably OK so lets get the carb out, check it out and see if there are any issues.

It is weird that the carb H screw is turned fully in....I am taking it that the limit cap is off? The only time I have seen this is when a saw has excessive bore wear so do the carb work and if that doesn't help, check the cylinder.

Is your air filter 100% clean as a dirty one will significantly richen the mixture? 

You could try taking the air filter off, start the machine and see if you grab the throttle that you get a puff of fuel vapour out of the back of the carb. If you do, it is a sign of wear on the piston, bore or both around the inlet side causing a bit of free-porting which isn't good.

 

[Ledburyjosh]

OK thanks.

 

I shall have a look at the carb, is there anything to be aware of whilst taking that off/apart?

 

Yes, the limiter caps have been removed.

 

There is oil residue around the air intake, would that be caused by the fuel vapour coming out the back of the carb?

[Ledburyjosh]

I have just been and checked the H screw, I may have mad an error 😬. It does actually have 1 full turn left before its fully wound in.... 

 

So given that should I just stick it back together and continue using it?