New Build. 372xp case, an X-torq cylinder and a 575xp piston.

[Rich Fife]

What did you hone that cylinder with? Looks kinda rough. Have you had success with it?

i went a bit aggressive with a dingle berry (flex hone)... that was due to the fact this cylinder had scoring.

Probably an illusion, but do those pistons have the same size wrist pin?

Same size.

Im assuming you already turned the 51mm piston down to 50mm? If not, how are you timing it?

Not yet, I have the dimensions, game plan is 95% lathe work and 5% mill work. The piston wrist pin to crown was identical... the skirt has to be adjusted. "Timing it"?

Will any portion of the top ring hit the space between the top of the plating and the squish band (aka ring of death)?

Nope, its All good.

About the ring pins. Pistons usually have a cast in boss to retain more of the pin than the piston thickness ordinarily could. You’re already making the piston 20 thou thinner on each side. How will you safely retain the pin?

Plan is to heat the piston and pull the pins... if that doesnt work I'll use a mill and machine them out... then relocate the pins, I'll freeze the pins, heat the piston to create an tighter interference fit.
OR
i can machine a jig and narrow the rings... to me, thats asking for trouble/failure.
I don't see any casted boss... this piston is meaty...

 

[Rich Fife]

Sifting through some parts on a rainy day.

 

[Rich Fife]

I have to get a few more parts, mod the muffler and tweak the carb... idk how old this carb is... maybe from 2014-2015-ish so I'm certain it should be rebuilt. Lol

 

[Rich Fife]

Made a little fixture to hold the piston. We cut the piston, now I have to clearance the pins from the outer diameter.

 

[Rich Fife]

Cutting the 5752xp in the lathe.

 

[Ketchup]

Nice lathe! What did you decide to do with the pins.

 

[Rich Fife]

Nice lathe! What did you decide to do with the pins.

I'm making a jig in-order to machine the inner diameter of the rings... this is my saw so if it grenades, no worries... it's all just junk parts anyway. The next one I do, I'll remove or machine the pins out and relocate them.

 

[Rich Fife]

It seems to be a little better...

 

[Rich Fife]

Nothing to write home about... but, Dylan is giving it some paces. I have to go back in and adjust the numbers a little...

 

[Ketchup]

I'm making a jig in-order to machine the inner diameter of the rings... this is my saw so if it grenades, no worries... it's all just junk parts anyway. The next one I do, I'll remove or machine the pins out and relocate them.

So currently running the stock piston? Did you modify the windows?

 

[Rich Fife]

So currently running the stock piston? Did you modify the windows?

No sir, the machined 575xp piston is in it... I still have to widen the intake approximately .060" and increase the intake duration slightly... test it, and then toss in the unlimited coil... I feel as if it wants or could be more than what it currently is... if that makes any sense.
It's out in the woods for the rest of the week... this weekend I'll see what the guys say and then make the changes.
I don't mess with piston pockets because they're for the fresh air charge... I'm trying to add more fuel to the case and less air... am I going about it the right way??? lol

 

[Ketchup]

Cool! How did the piston work out? Were you able to just skin it and pop it in or did you have to cut the ring lands deeper? Did the lathe cut the pins or were they inset enough?

 

[Rich Fife]

Cool! How did the piston work out?

Not too bad to be honest.

Were you able to just skin it and pop it in or did you have to cut the ring lands deeper?

Yep, just skimmed the piston, used OEM 50mm rings. No, I didn't have to clearance the rings... with that said, now there is effectively less room for carbon build up behind the rings... soooo yeah. Not the best route in my opinion. But, the saw was put into the box and its out in the woods today. The guys will.surely beat on it to see how it holds up.

Did the lathe cut the pins or were they inset enough?

Yes. The pins were cut, minimally, so they were flush with the outer diameter of the piston. I relieved them using a small Widia burr bit and made sure the ring could squeeze shut and move... all good so far.

 

[Rich Fife]

I have a stihl 056 piston that I am working on for a 500i...

 

[Rich Fife]

*s-word, I never posted what I did to the 575xp piston to make it work.... below is the video.

 

[Rich Fife]

This saw has gobs of torque when compared to a stock X-torq... yeah yeah, I know... it should as its ported.
I tossed in an unlimited coil... Big Difference! The rings are seating and the saw is gaining power. We had it fat for the woods and tonight we tuned it to where it would just hit the 4 stroke and then we adjusted it in the cut... I'll have to make a video on the tool I Machined to be able to easily adjust the L & H while cutting...
Tomorrow I'm going to open the intake wider and add a couple degrees of intake then do some more test cuts and comparisons.