MS 650 big end

[Megatron]

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.

[bobh]

Thanks all for your help.

Spent yesterday afternoon trying to track down the various parts for this job.

Got crankshaft, piston bearing and gasket set from DLA Engine Parts on ebay, less than £70 delivered for all 3

Non genuine piston and crank bearings were a little harder to track, after much research and several phone calls it seems the piston from the ms640 won't fit, spoke to the guys at Mister Solutions, turns out they're really helpful, went out of their way to try and help but in the end I had to bite the bullet and get genuine parts from them, so piston and crank bearings are coming in at a little under £130.

All in a fraction less than £200, more than I hoped for at the start, would have been a lot less if non genuine parts were available, but still worth it to get the saw sorted.

Next up is the crank puller thinking of making something along these lines

But how do you get the other side off?

[ame=http://www.youtube.com/watch?v=mT0oJ-0s758&feature=colike]Splitting Husqvarna chainsaw crank case 385xp - YouTube[/ame]

Or maybe this, but I know mine won't look as posh as this [ame=http://www.youtube.com/watch?v=2G-vapNwntw&feature=colike]Splitting 372 Crankcase - YouTube[/ame]

[Megatron]

Non genuine piston and crank bearings were a little harder to track, after much research and several phone calls it seems the piston from the ms640 won't fit, spoke to the guys at Mister Solutions, turns out they're really helpful, went out of their way to try and help but in the end I had to bite the bullet and get genuine parts from them, so piston and crank bearings are coming in at a little under £130.

 

What reason did Mister Solutions give for the piston not fitting, different part number?

Not to put too much of a downer but you could have bolted on a new aftermarket MS660 piston and cylinder for less than the cost of the OEM MS650 piston. But I would have probably gone with new OEM piston if the cylinder is in good condition.

 

For future reference you can also save money on flywheel side bearings. It is the clutch side which are proprietary to Stihl. You can usually get the same bearing (SKF, FAG) etc for much less if you buy direct from a bearing suppliers rather than going through Stihl. In this case you wanted a 6203 open type with C3 clearance.

 

In the second of the two videos that is the OEM Husqvarna tool.

 

Here, is some of what I use;

http://arbtalk.co.uk/forum/544588-post38.html

(On stihl saws I made a tool which looks more like the OEM tool for Stihl for the flywheel side)

 

Some very good info here (highly recommended);

http://www.arboristsite.com/chainsaw/40590-2.htm#post539218

(You will have to become a member to see the pictures, rather than red X's)

Edited October 30, 2011 by Megatron

[bobh]

Spot on advise Megatron

Just in time too as I was going to knock up the pullers/pushers tomorrow.

Bob

[bobh]

Quick update on this.

Stripped and rebuilt the saw today, seems to run fine but haven't had time to put it in any wood yet.

Thanks for all the advise, it really helped.

Good fun doing a full strip down and rebuild, was covered in black gunk in those normally inaccesable areas like behind the clutch.

[elfinwood saws]

Quick update on this.

Stripped and rebuilt the saw today, seems to run fine but haven't had time to put it in any wood yet.

Thanks for all the advise, it really helped.

Good fun doing a full strip down and rebuild, was covered in black gunk in those normally inaccesable areas like behind the clutch.

 

sometimes there,s ally swarf behind the clutch that cuts the sealing lip off the crankseal!