Ms390 piston rings

[Copygod69]

I am looking at the measurements and they should fit but could I throw these on the piston for the 49mm iron bore

Hyway piston rings 49mm fits Stihl TS360, TS400, 08, 039, MS390, Husqvarna 460, 570

High quality ductile split groove piston rings set of two Fits Stihl 08S, TS360, TS400, 039, MS390 Replaces OEM part 1127 034 3007 Husqvarna 460, 570 Replaces OEM part 503 28 90-46

www.hlsproparts.com

 

[ImpulseRocket]

I am looking at the measurements and they should fit but could I throw these on the piston for the 49mm iron bore

Hyway piston rings 49mm fits Stihl TS360, TS400, 08, 039, MS390, Husqvarna 460, 570

High quality ductile split groove piston rings set of two Fits Stihl 08S, TS360, TS400, 039, MS390 Replaces OEM part 1127 034 3007 Husqvarna 460, 570 Replaces OEM part 503 28 90-46

www.hlsproparts.com

As long as the rings are the same thickness, yes. Just make sure to check the end gaps.

Also, those are iron rings, not steel. The word "ductile" being the giveaway.

 

[Chainlube]

Looks like it will.

Model Profile: MS 390

 

[GW's Motorized]

You should see if you can find steel rings. Caber probably makes some

 

[francisjohn]

You can buy them on Amazon.

Amazon.com

It isn't as easy as matching up the bore to another bore. You have height and thickness. 47mm-48mm bores are 47mm/48mm x 2mm x 2mm. The 49mm is 49mm x 1.5mm x 2mm.

If you're not using a ring that matches the thickness and height, you're going to experience blowby.

Also if you're interested, I have a brand new 49mm top end for sale, with the head included. I bought the engine for my MS440 build and enough top ends. Cylinder will be cleaned out prior to being shipped and an be ported to a specific timing for more.

 

[GW's Motorized]

You can buy them on Amazon.

Amazon.com

It isn't as easy as matching up the bore to another bore. You have height and thickness. 47mm-48mm bores are 47mm/48mm x 2mm x 2mm. The 49mm is 49mm x 1.5mm x 2mm.

If you're not using a ring that matches the thickness and height, you're going to experience blowby.

Also if you're interested, I have a brand new 49mm top end for sale, with the head included. I bought the engine for my MS440 build and enough top ends. Cylinder will be cleaned out prior to being shipped and an be ported to a specific timing for more.

Is that a YD/LD100?

 

[francisjohn]

Is that a YD/LD100?

Nope. YD/LD is a 50mm bore. The 49mm is the 72cc "100cc"

I bought the top end back in April when Samger was selling them for $20. The CDH Iron Sleeve is literally just this engine's top end. Magically, CDH sells the head separately for $36, the cylinder kit for $50, and the only bottom end listing for a 66cc/69cc is from that engine.

As of right now, the only and cheapest way would be to buy it from China for $35 shipped. Next up would be from CDH as the "Iron Sleeve" for $50. Plus, they don't clean it out for you either, but I will

The 49mm out of box is horrible. The timing on it is so bad that there is no recorded data for durations that low. The port map isn't from this engine, but this is the port map to my current 49mm top end and what I turned it into. Once I did that, it was a real beastalinni.