Stihl ms290/390 pop-up piston kit - To be sold soon??

[Terry Syd]

Beautiful work! I'm running a cheap Huztl jug on my 029, it looked good out of the box and I just stuck it straight on the saw. Wish it had come with a piston like that! Did you do a before and after test on the increase in compression?

 

[Dub11]

I know there will be some testing with this pop up I sent two saws. One oem 49mm the other Cross 49mm to see how the pop up does in the different heads.

 

[drf256]

Beautiful work! I'm running a cheap Huztl jug on my 029, it looked good out of the box and I just stuck it straight on the saw. Wish it had come with a piston like that! Did you do a before and after test on the increase in compression?

No Terry

I did it for a young member on the AS for nothing. Guy flaked out on me, posted something 2 months later, then disappeared.

Never even paid me the $10 shipping back to him.

 

[Terry Syd]

Never even paid me the $10 shipping back to him.

So you do the guy a favor and weld up his piston and turn it down - equipment, welding rod/s, time and expertise - and SOB couldn't even bother to send you a lousy $10 to cover the shipping.

If you remember his name (like from his address for shipping), let me know - just between us, I won't tell anyone else on the forum.

 

[drf256]

So you do the guy a favor and weld up his piston and turn it down - equipment, welding rod/s, time and expertise - and SOB couldn't even bother to send you a lousy $10 to cover the shipping.

If you remember his name (like from his address for shipping), let me know - just between us, I won't tell anyone else on the forum.

I've got an idea.

On the AS somewhere.

I'm over it.

 

[srcarr52]

I'll have to get on Nathan about this. It seems like I did the pop up for this months ago. @Black Dog Chainsaw

 

[Black Dog Chainsaw]

I'll have to get on Nathan about this. It seems like I did the pop up for this months ago. @Black Dog Chainsaw

You did and I have been a wonderous slacker! (Honestly just changed jobs and been working 50-60hrs/week). Anyhow I have some vacay coming for the NY GTG and I'll see if I can extend a day to get this done... ugh!!! I need 5 more hours every day!!!

 

[Dub11]

You did and I have been a wonderous slacker! (Honestly just changed jobs and been working 50-60hrs/week). Anyhow I have some vacay coming for the NY GTG and I'll see if I can extend a day to get this done... ugh!!! I need 5 more hours every day!!!

Only 5 I need like an extra 27 hours lol

 

[Dub11]

Any progress?

 

[Time's Standing Stihl]

@Black Dog Chainsaw

 

[Black Dog Chainsaw]

Yes actually I got 2 of them together over memorial day weekend... have been collecting info on each combo's compression and will take them out for a spin before I release results.

 

[smokey7]

So any gain in comp? Does it feel like it has a pair of nuts now?

 

[Terry Syd]

So it this a real thing? I mean, like, I'm not really just sitting around waiting for a 'red tailed skink' to nab with my burlap bag like I did back in the Boy Scouts - am I?

Anybody have a picture of any high compression 039/390 piston? Rough, dirty, nasty machining - however embarrassing it may look.

 

[Gentleman]

So it this a real thing? I mean, like, I'm not really just sitting around waiting for a 'red tailed skink' to nab with my burlap bag like I did back in the Boy Scouts - am I?

Anybody have a picture of any high compression 039/390 piston? Rough, dirty, nasty machining - however embarrassing it may look.

Whenever @Black Dog Chainsaw sends me the prototype

 

[Black Dog Chainsaw]

Whenever @Black Dog Chainsaw sends me the prototype

Prototype in route. It fits hyway, cross and OEM. Dry fit numbers showing 10-15psi bump. I was looking for a little more but had to make sacrifices to get all three cylinders to fit. I've got the numbers in the shop and will post them later. I think whoever remanufactures them can easily add 0.003-0.005" more to the height of the pop-up and we can get 15-20psi. Again this was
A dry fit test run and everything fit perfectly. If Bruce @Gentleman wants me to I will test a piston or two from the first production run to ensure quality and recheck measurements. I was hoping for some run time before I sent it off but 6 assemblies and disassemblies kinda took the wind out of my sails. [emoji53]

Just so we are clear. I tested all three cylinders with and without the pop up on the same crank, bearings, caber/OEM rings, etc. All three received a decomp plug for the compression tests. Don't be alarmed if you think the numbers are a little low. After run time, coating with fuel/oil, and the rings seat in... I usually expect 7-12psi more than the dry fit numbers.

 

[Terry Syd]

but 6 assemblies and disassemblies kinda took the wind out of my sails.

Just doing one disassembly and reassembly of this model of saw takes the wind out of my sails. I hate working on these saws.

I'll take a 15psi bump in compression.

 

[Black Dog Chainsaw]

Just doing one disassembly and reassembly of this model of saw takes the wind out of my sails. I hate working on these saws.

I'll take a 15psi bump in compression.

Honestly these saws aren't bad runners. The are horrible to work on and have bad pre-air filtration... but I can do them in my sleep after doing so many. The AM companies would do way better to check their squish band. Several of these AM kits have over 0.050 squish!!


Sent from my iPhone using Tapatalk

 

[Stihlsmoking]

So these things in production yet ? Lol

 

[Black Dog Chainsaw]

So these things in production yet ? Lol

I just mailed the prototype piston to Bruce this weekend so middle of next week he will have it in his hands. I would have got pics of everything but I broke the camera on my iPhone...

 

[Fruecrue]

Any idea on the timeframe / expected availability on these?
I've got an MS390 and an 039 now, two more MS390s on their way here.
It would be cool to have a couple ready by October for Randy's GTG.
@Gentleman