Pop up pistons

[Chainsaw Mick]

Can anyone help out there with a supplier of pop up pistons?
I recently took apart a Ripsaw MS201 and they have a very nicely done pop up piston which seems to have Stihl part number on the underside and the numbers on the top of the piston.
I’ve measured up and the pop up is .030” bigger than standard piston so I’ve ruled out they turned down a standard piston.

 

[PA Dan]

That is not a pop up piston in the traditional sense. Stihl changed the piston design sometime in the last 2 years and that is the new piston.

 

[PA Dan]

That piston is also specific to the cylinder and the same with the flat top pistons from my experience. New oem cylinder kits came with the flat top pistons and cylinder.

 

[Chainsaw Mick]

That is not a pop up piston in the traditional sense. Stihl changed the piston design sometime in the last 2 years and that is the new piston.

Thanks, so I should be able to get that piston direct from dealer. I’m gonna look into that cause these saws do produce way more power than the older ones.

 

[PA Dan]

Thanks, so I should be able to get that piston direct from dealer. I’m gonna look into that cause these saws do produce way more power than the older ones.

If the saw has that p/c combonation than that would work. You should be able to order it.

 

[Gullet]

Edit...
My bad, I misunderstood.
Not easy to follow.

 

[Gullet]

Find a machinist that will measure your cylinder and turn down the piston on a lathe would be ideal.
Prolly better than ordering a OEM piston to fit some random cylinder.

 

[Chainsaw Mick]

Find a machinist that will measure your cylinder and turn down the piston on a lathe would be ideal.
Prolly better than ordering a OEM piston to fit some random cylinder.

I’ve done measurements and dropped another OEM pot on it and all seems to line up nice. So I’d like it if I could get OEM pistons to just drop straight in to other saws.
Im in uk and having trouble finding that piston so now I’m wondering if it’s US spec 201’s that only have them? Any one know part number for piston?

 

[Gullet]

You a machinist?
Lathe?
Milling head??

 

[DND 9000]

Im in uk and having trouble finding that piston so now I’m wondering if it’s US spec 201’s that only have them? Any one know part number for piston?

No it is not only a US piston. It`s the generall new version on the C-M models. The piston is part: 1145 030 2005

Edit:
Only valid for cylinder 1145 020 1202. The cylinder contains the piston.

 

[Chainsaw Mick]

No it is not only a US piston. It`s the generall new version on the C-M models. The piston is part: 1145 030 2005

Edit:
Only valid for cylinder 1145 020 1202. The cylinder contains the piston.

Thanks, put in your part numbers and I found them over here in the UK. The applications for them are on 201 models I’ve never seen but a friend did mention these recently but he’s never seen then either.
MS 201 C-EM, MS 201 C-EM Z, MS 201 C-M, MS 201 C-M-Z, MS 201 TC-M-Z

 

[Chainsaw Mick]

You a machinist?
Lathe?
Milling head??

Done some machine work so not out of my remitt’, but got a friend that is very good with all this and would get involved.

 

[Ketchup]

Done some machine work so not out of my remitt’, but got a friend that is very good with all this and would get involved.

As mentioned above, the new version 201t has both the pop-up piston and a combustion chamber machined to match. That means the older style piston will make significantly less compression. If you machine a flat top piston to the shape of the new pop-up you will also need to lower the cylinder. That means you either cut off the transfer nipple or deck the case. It's unfortunately complicated to mod these.
Going the other way, the new piston does not fit in the old jug. The chamber or pop-up must be cut to fit.

 

[Chainsaw Mick]

As mentioned above, the new version 201t has both the pop-up piston and a combustion chamber machined to match. That means the older style piston will make significantly less compression. If you machine a flat top piston to the shape of the new pop-up you will also need to lower the cylinder. That means you either cut off the transfer nipple or deck the case. It's unfortunately complicated to mod these.
Going the other way, the new piston does not fit in the old jug. The chamber or pop-up must be cut to fit.

I was playing around today checking other piston pot combinations and yeah, the uk T-CM hits the squish band even with the gasket back in it. So it’s a complete pot n piston replacement like was mentioned right at the start of this post.
So now I’ve got the correct numbers for kit I’m now wanting to know, what it the difference between T-CM and TC-M-Z?

 

[DND 9000]

T=Tophandle saw
C= Comfort Feature (can be different things)
M= m-tronic
Z= Spark arrestor in the muffler (mostly US, NZ, AUS, CDN versions, Europe does not have it)