Spuds Porting and Tuning Thread

[spudulike]

can you finish my saw before you lose an arm please?

 

Still waiting for the seal to arrive so I can reassemble it:thumbdown:

[div_h]

Still waiting for the seal to arrive so I can reassemble

 

I'm in no rush, take your time:thumbup1: but I do want a go of it:blushing:

[spudulike]

Still waiting for the seal to arrive so I can reassemble

 

I'm in no rush, take your time:thumbup1: but I do want a go of it:blushing:

And so shall it be and you will be happy with it, better than what could have happened if you had run the machine as it was:thumbdown:

 

Fingers crossed it will arrive tomorrow!

[wyk]

So, I've been milling with my 2177 for a bit now, and let me tell you - richen the hell out of your saws if you are going to be milling with them. Especially if they are ported. I noticed a lot of compression loss today after a few long cuts. I put the thing on the gauge and it's blowing 100psi! I think the exhaust also might breathe a bit too well for milling. I also suspect the piston fit on the 77cc hyway wasn't very good, and may have contributed to it wearing.

 

All I had laying about was a 365 open port top end. So, I decided to mildly port that and put it on the saw to see if she would mill worth a damn. Here's the first pass grinding on the lowers:

 

 

 

 

 

The images make it look like I went deep into the barrel, but it's only a few mm's. I've ground out to the edges as far as I cared to, and opened it up to pull more fuel from the case. I didn't go crazy since she's an open port, but she does run very nicely now. I added some timing and reshaping to the top of the ports, but didn't go nuts since I mostly want mid range torque. Somehow, I doubt she'll pull as well as the old hyway did, let alone as well as a mm 560xp. I just hope she can mill small planks decently until I decide on a replacement.

[spudulike]

So, I've been milling with my 2177 for a bit now, and let me tell you - richen the hell out of your saws if you are going to be milling with them. Especially if they are ported. I noticed a lot of compression loss today after a few long cuts. I put the thing on the gauge and it's blowing 100psi! I think the exhaust also might breathe a bit too well for milling. I also suspect the piston fit on the 77cc hyway wasn't very good, and may have contributed to it wearing.

 

All I had laying about was a 365 open port top end. So, I decided to mildly port that and put it on the saw to see if she would mill worth a damn. Here's the first pass grinding on the lowers:

 

 

 

 

 

The images make it look like I went deep into the barrel, but it's only a few mm's. I've ground out to the edges as far as I cared to, and opened it up to pull more fuel from the case. I didn't go crazy since she's an open port, but she does run very nicely now. I added some timing and reshaping to the top of the ports, but didn't go nuts since I mostly want mid range torque. Somehow, I doubt she'll pull as well as the old hyway did, let alone as well as a mm 560xp. I just hope she can mill small planks decently until I decide on a replacement.

 

Not nice to screw up a saw ou have done lots of work on, milling is pretty tough on saws though as the saw gets little time to cool down and that build up of heat can cause issues.

 

Nice work on the 365 though!

[wyk]

Not nice to screw up a saw ou have done lots of work on, milling is pretty tough on saws though as the saw gets little time to cool down and that build up of heat can cause issues.

 

Nice work on the 365 though!

 

Thanks, bud. I thought she was safe at 13.8K since she ran at 14.5 easily for felling all day long without a problem. But turns out it wasn't rich enough. Either that or I just should have given her more breaks than I did. It's a mistake I won't make in the future. I was in a hurry today and just kept going and going. There was a ton of oil in the case, so I suspect it may have been a heat issue.

 

The new cylinder looks cool with the porting the way it is, but it's more looks than go, I suspect. Open ports tend to be lackluster on torque. I only raised the exhaust back up to a couple of degrees more than where she would sit with the gasket. I mostly widened it for timing. She sits at .027 squish without the gasket. I'll run her some tomorrow and hook up the compression tester to see how healthy she is. I will be surprised if she runs close with my ported 361 now.

[wisecobandit]

Is the topend coating worn wyk or not?

[wyk]

Is the topend coating worn wyk or not?

 

On the old hyway? Well, it is a bit, but I suppose I could reuse it if I wanted to. The problem is, especially after the difficulty I had fitting this new top end onto the new piston, the old jug had more tolerance than I cared for even before this happened. It just was never that "damn this is a pain in the ass to stuff a piston into" fit that you usually get. I was hoping dual rings would solve any issues, but I suspect it was a contributing factor. I was running cabers, too.

[wisecobandit]

Hmm was just thinking the stihl 064 piston fits as a direct swap but a tadge higher so you may want to fit base gasket and squish test before your confident it wont hit the top removing the base gasket or if you wanted to go make a pop up the 272xp as they are a fraction taller again.

[wyk]

Hmm was just thinking the stihl 064 piston fits as a direct swap but a tadge higher so you may want to fit base gasket and squish test before your confident it wont hit the top removing the base gasket or if you wanted to go make a pop up the 272xp as they are a fraction taller again.

 

D'ya know the width on that 064 piston skirt vs the HyWay? I had it to within 1mm. Which, for milling, is prolly not a good idea. The squish on this BB was .028 or so. Which makes sense it would be nearly the same as the stock 65cc piston is.