Hybrid clonesaw 365 with a 390 topend - aka the "86'r from youtube"

[Jake Dykstra]

I see the stroke is the same, are the pin's the same diameter?

Should be 12mm on both is my understanding.

 

[HumBurner]

That would be worth the work!

I'd love to try that out on some trees.

 

[Jake Dykstra]

I'd love to try that out on some trees.

It will be faster for sure. Hopefully by guys like upstate doi g these builds the big 3 will start looking at lightweight big cc options in the future

 

[upstateamish]

Was away for the weekend but sounds like there's still a bit of interest in this project!

Had a good conversation last night with my buddy discussing project viability (e.g. moving from the artisin crafted cases to something more repeatable) and some next steps on the CNC side of things. He's going to get some estimates around building fixtures that would allow the machine work be done on the case halves (clearance for the crankshaft, the cylinder and potenially bore the bearing pockets to accept 390 style crank bearings.)

He's already got the case halves to go off of but I've got some new parts inbound to him for mock up and measurment purposes (highway 390 big bore top end from wolf creek and wrist pin, crankshaft, and clutch side 390 crank bearing with the integrated seal from the duke.) We figured start with the clutch side since that's the one that has the crankshaft bushing that I'm not in love with

He also weighed the prototype 3 PHO - 16.2lbs (said it was about half full of gas / oil) with large inner/outer bar spikes. So I think weighs in roughly about the weight I had with the 2nd prototype.

I thought 86?

I think I want one. But autotune.

autotune could be interesting

Thats exactly whats on my bench next. 592 should be here next week!
I was thinking of starting with a 585 if I can't get enough weight off the 592 piston.

the transfers of the 592 / 585 cylinders are front fed, the 372 case is pretty thin there so I'm curious how you plan to get around that. I wonder if you might be able to use a 576 bottom end (the front bolts would need to be redone, but maybe it would be work?)

I'd love to try that out on some trees.

If the the CNC logistics work out, might have an a way to make these more repeatable. Would be neat to be able to get some in hands of people who would use them more than I can to see where failure points are.

It will be faster for sure. Hopefully by guys like upstate doi g these builds the big 3 will start looking at lightweight big cc options in the future

I assume once new 564 runs through the bugs it may have, it could be the upsized on the CC range. I'm sure they've got the beancounters working on the numbers for it

 

[Jake Dykstra]

the transfers of the 592 / 585 cylinders are front fed, the 372 case is pretty thin there so I'm curious how you plan to get around that. I wonder if you might be able to use a 576 bottom end (the front bolts would need to be redone, but maybe it would be work?)



I assume once new 564 runs through the bugs it may have, it could be the upsized on the CC range. I'm sure they've got the beancounters working on the numbers for it

Not planning on using the 372 platform for the 592 build. Going to use the 572 platform.
The 564 looks interesting for what it is but it has a short stroke so not much chance of growing up to be a big boy.

 

[Ketchup]

Not planning on using the 372 platform for the 592 build. Going to use the 572 platform.
The 564 looks interesting for what it is but it has a short stroke so not much chance of growing up to be a big boy.

What is the stroke? 500i is short stroke. Interesting.

Edit: My memory is going. We already hashed this out a bit in the 564 thread. Does anyone have an official measurement on stroke or bore?

 

[EFSM]

What is the stroke? 500i is short stroke. Interesting.

Why are the new saws going short stroke? That makes sense on a 4 stroke (more room for valves) but a long stroke on a 2 stroke engine allows for more port area per degree of rotation. Is it a weight reduction thing? You can build the rotating parts lighter with a short stroke engine and there will be less strength required in the crankcase.

 

[Ketchup]

That seems like part of it. Weight savings.
The 564 literature says less vibration and slimmer case. That may also mean less case volume which tracks with 500i and fuel injection not needing the same port time area. Funny though, 500i has a long intake duration.

 

[Jake Dykstra]

I heard 48mm bore like the 572 so 33.5ish stroke