China Big Bore 660 build

[Powerstroke Cowboy]

You can delete a post you made.

But my eyes saw it, before you nuked it.

Yes I did, but not in this thread. I read it, and decided I didn't need to join in on the conversation. Or more like how it might go...

If you want, I can repost it........

 

[Rich Fife]

FT 56mm cylinder.

 

[Rich Fife]

Piston comparison

 

[Maintenance Chief]

FT 56mm cylinder.

Unmodified?

 

[Rich Fife]

AM piston

 

[Rich Fife]

661 piston

 

[Rich Fife]

Unmodified?

Yes, unmodified. Besides the cross-hatches.

 

[Maintenance Chief]

I bought one of the Dukes cheap BB066 kits. Its just a touch nicer.

 

[Rich Fife]

I bought one of the Dukes cheap BB066 kits. Its just a touch nicer.

I'll have to check them out. I'm going to use the parts that I have just to see what I can do to it. It Should be interesting.

 

[Powerstroke Cowboy]

Thanks for the piston dimensions Rich. I just ordered a ms661 piston. I think it'll be just what the doctor ordered.

 

[drf256]

Twisted Up 56 Mirrometer 660 Jug Build.

We need more build threads here, period. This may be an epic fail, but the work is worth it to further our knowledge/passion for these pieces of lawn equipment we hold so dear. It’s for my pal @MustangMike , so it’s worth the effort and likely embarrassment. So here it goes...

opeforum.com

 

[Rich Fife]

Thanks for the piston dimensions Rich. I just ordered a ms661 piston. I think it'll be just what the doctor ordered.

You're welcome.

 

[Rich Fife]

Twisted Up 56 Mirrometer 660 Jug Build.

We need more build threads here, period. This may be an epic fail, but the work is worth it to further our knowledge/passion for these pieces of lawn equipment we hold so dear. It’s for my pal @MustangMike , so it’s worth the effort and likely embarrassment. So here it goes...

opeforum.com

I like the skirt width of the 395 piston. I wish the 661s were .200" wider than what they are... then I think we'd have something. I haven't weighed the AM piston to the OEM 661 piston... I'll have to look deeper into your post to see what the 395 piston weighs.

 

[drf256]

I like the skirt width of the 395 piston. I wish the 661s were .200" wider than what they are... then I think we'd have something. I haven't weighed the AM piston to the OEM 661 piston... I'll have to look deeper into your post to see what the 395 piston weighs.

Figured I could save you some time.

Ran mine against a few well done 54mm OEM saws and it kept up but wasn’t as good. That was with a buried 36” 404 bar in rock hard dry oak at the NY GTG years ago.

I did another with the big bore piston flipped backwards and a near stock exhaust width. That one beat a few good ported oem’s. I probably timed the fingers wrong. Back then we were all opening them up before the mains.

 

[Seachaser]

For those interested, they have them for a tad less than $300 shipped on Amazon right now. Complete.

https://www.amazon.com/FARMMAC-Chainsaw-Powerhead-Gasoline-Compatible/dp/B0B4SL8X9L/ref=mp_s_a_1_1_sspa?crid=3VILDFPLX35J9&dib=eyJ2IjoiMSJ9.jSwcBAlPL_u33XRXZzG_muqaKjFN0aBFeKgUilur_WEe2IUEnZL9CdlgQG1SoDtG_N_yHq-MvpM_8c2vG-ZxL0dJQ0OIjcuri0iiyaAcUTW8Gfgq9EWE5t8TLXkv_23c63bCs57w3gGVsUQ3n0pO1WGJBGvdF0_P8Pe03R8S-XWgdA7DEq2bVmr1IM-c723BLGAy69g7QRRY5qycWnRmjQ.Yk_FW2W6O5wkq_pKLvECoZ8dSfWYpm9Y7kNTzavAsz4&dib_tag=se&keywords=neo-tec&qid=1710921263&sprefix=neo-tec%2Caps%2C144&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRm&tag=hlsupplyaffil-20&th=1

 

[srcarr52]

For those interested, they have them for a tad less than $300 shipped on Amazon right now. Complete.

https://www.amazon.com/FARMMAC-Chainsaw-Powerhead-Gasoline-Compatible/dp/B0B4SL8X9L/ref=mp_s_a_1_1_sspa?crid=3VILDFPLX35J9&dib=eyJ2IjoiMSJ9.jSwcBAlPL_u33XRXZzG_muqaKjFN0aBFeKgUilur_WEe2IUEnZL9CdlgQG1SoDtG_N_yHq-MvpM_8c2vG-ZxL0dJQ0OIjcuri0iiyaAcUTW8Gfgq9EWE5t8TLXkv_23c63bCs57w3gGVsUQ3n0pO1WGJBGvdF0_P8Pe03R8S-XWgdA7DEq2bVmr1IM-c723BLGAy69g7QRRY5qycWnRmjQ.Yk_FW2W6O5wkq_pKLvECoZ8dSfWYpm9Y7kNTzavAsz4&dib_tag=se&keywords=neo-tec&qid=1710921263&sprefix=neo-tec%2Caps%2C144&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRm&tag=hlsupplyaffil-20&th=1

I build one of these for sawfest and the transfers where really jacked up in the cylinder. It took me forever to straighten them out, I ended up grinding out of one transfer just trying to get the same entrance angles on each side.

 

[Rich Fife]

This saw build continues to become more and more interesting... stock AM piston has interference with the squish without a base gasket. With the base gasket of .020" the squish is .002"... the 661 piston is .192"-ish taller than the AM piston... looking for some thick copper sheets to make a base gasket... even then, I have a feeling this saw will need a two piece cylinder and a timing change.

 

[Rich Fife]

Stock numbers with a 'thick' base gasket. And some other measurements.

Exh 97*
X-fer 127*
Int 87*
BD 30*
SQ .034"

Free porting with AM piston.

 

[Rich Fife]

Thanks for the piston dimensions Rich. I just ordered a ms661 piston. I think it'll be just what the doctor ordered.

661 won't work. Too tall and it Freeports worse.
Onto the 056 magnum and 395xp.

 

[Rich Fife]

Why not.